Programs & Examples On #Android

Android is Google's mobile operating system, used for programming or developing digital devices (Smartphones, Tablets, Automobiles, TVs, Wear, Glass, IoT). For topics related to Android, use Android-specific tags such as android-intent, not intent, android-activity, not activity, android-adapter, not adapter etc. For questions other than development or programming, but related to Android framework, use the link:

Android Fragment no view found for ID?

An answer I read on another thread similar to this one that worked for me when I had this problem involved the layout xml.

Your logcat says "No view found for id 0x7f080011".

Open up the gen->package->>id and then look for id 0x7f080011.

When I had this problem, this id belonged to a FrameLayout in my activity_main.xml file.

The FrameLayout did not have an ID (there was no statement android:id = "blablabla").

Make sure that all of your components in all of your layouts have IDs, particularly the component cited in the logcat.

How to set ANDROID_HOME path in ubuntu?

I was facing the same problem with linux ANDROID_HOME path

1- Add parameters

2- Make or Rebuild project

3- Restart your PC

How to add parameters using terminal:

Open your terminal write

gedit .bashrc

another window will be open and then add the following lines at the end of the windows.

export ANDROID_HOME=$HOME/Android/Sdk
export PATH=$PATH:$ANDROID_HOME/tools 
export PATH=$PATH:$ANDROID_HOME/platform-tools

then back to terminal and type

source .bashrc

to save your changes in bashrc file at the end restart your computer.

Save bitmap to location

The way I found to send PNG and transparency.

String file_path = Environment.getExternalStorageDirectory().getAbsolutePath() +
File dir = new File(file_path);

String format = new SimpleDateFormat("yyyyMMddHHmmss",
       java.util.Locale.getDefault()).format(new Date());

File file = new File(dir, format + ".png");
FileOutputStream fOut;
try {
        fOut = new FileOutputStream(file);
        yourbitmap.compress(Bitmap.CompressFormat.PNG, 85, fOut);
     } catch (Exception e) {

Uri uri = Uri.fromFile(file);     
Intent intent = new Intent(android.content.Intent.ACTION_SEND);
intent.putExtra(android.content.Intent.EXTRA_SUBJECT, "");
intent.putExtra(android.content.Intent.EXTRA_TEXT, "");
intent.putExtra(Intent.EXTRA_STREAM, uri);

startActivity(Intent.createChooser(intent,"Sharing something")));

How to add Android Support Repository to Android Studio?

Found a solution.

1) Go to where your SDK is located that android studio/eclipse is using. If you are using Android studio, go to extras\android\m2repository\com\android\support\. If you are using eclipse, go to \extras\android\support\

2) See what folders you have, for me I had gridlayout-v7, support-v4 and support-v13.

3) click into support-v4 and see what number the following folder is, mine was named 13.0

Since you are using "", change this to reflect what version you have, for example I have support-v4 so first part v4 stays the same. Since the next path is 13.0, change your 18.0 to:


This worked for me, hope it helps!


I noticed I had android studio set up with the wrong SDK which is why originally had difficulty updating! The path should be C:\Users\Username\AppData\Local\Android\android-sdk\extras\

Also note, if your SDK is up to date, the code will be:


Datepicker: How to popup datepicker when click on edittext

Kotlin port, call the setDatePicker function

private fun setDatePicker(dateEditText: EditText) {

    val myCalendar = Calendar.getInstance()

    val datePickerOnDataSetListener = DatePickerDialog.OnDateSetListener { _, year, monthOfYear, dayOfMonth ->
        myCalendar.set(Calendar.YEAR, year)
        myCalendar.set(Calendar.MONTH, monthOfYear)
        myCalendar.set(Calendar.DAY_OF_MONTH, dayOfMonth)
        updateLabel(myCalendar, dateEditText)

    dateEditText.setOnClickListener {
        DatePickerDialog(this@YourActivityName, datePickerOnDataSetListener, myCalendar
                .get(Calendar.YEAR), myCalendar.get(Calendar.MONTH),

private fun updateLabel(myCalendar: Calendar, dateEditText: EditText) {
    val myFormat: String = "dd-MMM-yyyy"
    val sdf = SimpleDateFormat(myFormat, Locale.UK)

How to use data-binding with Fragment

Even the other answers may work well, but I want tell best approach.

Use Binding class's inflate as recommended in Android Documentation.

One option is to inflate by DataBindingUtil but when only you don't know have generated binding class.

--You have auto generated binding class, use that class instead of using DataBindingUtil.

In Java

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    HomeFragmentBinding binding = HomeFragmentBinding.inflate(inflater, container, false);
    //set binding variables here
    return binding.getRoot();

In Kotlin

lateinit var binding: HomeFragmentBinding 
override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
    binding = HomeFragmentBinding.inflate(inflater, container, false)
    return binding.root

In DataBindingUtil class documentation you can see.


T inflate (LayoutInflater inflater, 
                int layoutId, 
                ViewGroup parent, 
                boolean attachToParent)

Use this version only if layoutId is unknown in advance. Otherwise, use the generated Binding's inflate method to ensure type-safe inflation.

If your layout biniding class is not generated @See this answer.

How can I get color-int from color resource?

Most Recent working method:


Using ADB to capture the screen

To save to a file on Windows, OSX and Linux

adb exec-out screencap -p > screen.png

To copy to clipboard on Linux use

adb exec-out screencap -p | xclip -t image/png

How do I hide a menu item in the actionbar?

For those using the Appcompat library: If your Activity subclasses ActionBarActivity, you can call supportInvalidateOptionsMenu()

Seen here:

Where to install Android SDK on Mac OS X?

My personal preference is to put it in ~/opt/local/android-sdk-mac or /Developer/android-sdk-mac the latter being where Xcode and all the Apple Dev tools are held.

Scrollview vertical and horizontal in android

use this way I tried this I fixed it

Put All your XML layout inside


I explained this in this link vertical recyclerView and Horizontal recyclerview scrolling together

Difference between Activity and FragmentActivity

FragmentActivity is part of the support library, while Activity is the framework's default class. They are functionally equivalent.

You should always use FragmentActivity and instead of the platform default Activity and classes. Using the platform defaults mean that you are relying on whatever implementation of fragments is used in the device you are running on. These are often multiple years old, and contain bugs that have since been fixed in the support library.

java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1888, result=0, data=null} to activity

this is my case

startActivityForResult(intent, PICK_IMAGE_REQUEST);

I defined two request code PICK_IMAGE_REQUESTand SCAN_BARCODE_REQUEST with the same value, eg.

static final int BARCODE_SCAN_REQUEST = 1;

static final int PICK_IMAGE_REQUEST = 1;

this could also causes the problem

Set Focus on EditText

For Xamarin.Android I have created this extension.

public static class ViewExtensions
    public static void FocusEditText(this EditText editText, Activity activity)
        if (editText.RequestFocus())
            InputMethodManager imm = (InputMethodManager)activity.GetSystemService(Context.InputMethodService);
            imm.ShowSoftInput(editText, ShowFlags.Implicit);

Android "gps requires ACCESS_FINE_LOCATION" error, even though my manifest file contains this

My simple solution is this

if (ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) ==
        PackageManager.PERMISSION_GRANTED &&
        ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) ==
        PackageManager.PERMISSION_GRANTED) {
} else {
    Toast.makeText(this, R.string.error_permission_map, Toast.LENGTH_LONG).show();

or you can open permission dialog in else like this

} else {
   ActivityCompat.requestPermissions(this, new String[] {
      Manifest.permission.ACCESS_COARSE_LOCATION }, 


After a great update, check that the applicationId of the build.gradle (Module: app) and the package in AndroidManifest.xml are identical. I had the same problem and so I solved it.

How do I set up IntelliJ IDEA for Android applications?

Another way to identify the correct SDK is to install Android Studio, create a new project, go to project structure, SDK Location and find where the SDK was installed.

I found using the default installation process on a mac that the SDK home folder was in the /Users/'yourUser'/Library/Android/sdk folder. Make sure you have enabled your Mac to view the Library folder.

Creating a button in Android Toolbar

I have added text in ToolBar :


<menu xmlns:android=""

        app:showAsAction="never" />

boolean onCreateOptionsMenu(Menu menu) {
    inflater = getMenuInflater();
    inflater.inflate(, menu);
    return true;

public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        // action with ID action_refresh was selected
            Toast.makeText(this, "Skip selected", Toast.LENGTH_SHORT)
    return true;

GSON throwing "Expected BEGIN_OBJECT but was BEGIN_ARRAY"?

public ChannelSearchEnum[] getChannelSearchEnum(Response response) {
        return[].class, ObjectMapperType.GSON);

Above will solve and passing response will returned mapped object array of the class

Android: Proper Way to use onBackPressed() with Toast

I just had this issue and solved it by adding the following method:

public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
             // click on 'up' button in the action bar, handle it here
             return true;

            return super.onOptionsItemSelected(item);

Making authenticated POST requests with Spring RestTemplate for Android

Slightly different approach:

MultiValueMap<String, String> headers = new LinkedMultiValueMap<String, String>();
headers.add("HeaderName", "value");
headers.add("Content-Type", "application/json");

RestTemplate restTemplate = new RestTemplate();
restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());

HttpEntity<ObjectToPass> request = new HttpEntity<ObjectToPass>(objectToPass, headers);

restTemplate.postForObject(url, request, ClassWhateverYourControllerReturns.class);

Change icons of checked and unchecked for Checkbox for Android

One alternative would be to use a drawable/textview instead of a checkbox and manipulate it accordingly. I have used this method to have my own checked and unchecked images for a task application.

how to get all child list from Firebase android

FirebaseDatabase mFirebaseDatabase = FirebaseDatabase.getInstance();
 DatabaseReference databaseReference =    mFirebaseDatabase.getReference(FIREBASE_URL);
        databaseReference.addValueEventListener(new ValueEventListener() {
            public void onDataChange(DataSnapshot dataSnapshot) {

                for (DataSnapshot childDataSnapshot : dataSnapshot.getChildren()) {
                    Log.v(TAG,""+ childDataSnapshot.getKey()); //displays the key for the node
                    Log.v(TAG,""+ childDataSnapshot.child(--ENTER THE KEY NAME eg. firstname or email etc.--).getValue());   //gives the value for given keyname
        public void onCancelled(DatabaseError databaseError) {


Hope it helps!

How can I get current date in Android?

SimpleDateFormat df = new SimpleDateFormat("dd-MMM-yyyy");
String date = df.format(Calendar.getInstance().getTime());

How to restart adb from root to user mode?

This is a very common issue.

One solution is to kill adb server and restart it through command prompt. Sometimes this may not help out.

Just go to Window Task Manager to kill adb process and restart Eclipse.

Will work perfect :)

What is setContentView(R.layout.main)?

Set the activity content from a layout resource. The resource will be inflated, adding all top-level views to the activity.

  • Activity is basically a empty window
  • SetContentView is used to fill the window with the UI provided from layout file incase of setContentView(R.layout.somae_file).
  • Here layoutfile is inflated to view and added to the Activity context(Window).

Phone: numeric keyboard for text input

<input type="text" inputmode="numeric">

With Inputmode you can give a hint to the browser.

How to Parse a JSON Object In Android

JSONArray jsonArray = new JSONArray(yourJsonString);

for (int i = 0; i < jsonArray.length(); i++) {
     JSONObject obj1 = jsonArray.getJSONObject(i);
     JSONArray results = patient.getJSONArray("results");
     String indexForPhone =  patientProfile.getJSONObject(0).getString("indexForPhone"));

Change to JSONArray, then convert to JSONObject.

java.lang.NoClassDefFoundError:failed resolution of :Lorg/apache/http/ProtocolVersion

In your AndroidManifest.xml add this two-line.

<uses-library android:name="org.apache.http.legacy" android:required="false"/>

See this below code

        <activity android:name=".activity.SplashActivity">
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

        <uses-library android:name="org.apache.http.legacy" android:required="false"/>

Android Studio-No Module

Go to Project setting enter image description here

CHECK if the project setting is like this,if the module that you want is show in here enter image description here

IF the module that you want or "Module SDK" is not show or not correct.

then go to the module's build.gradle file to check if the CompileSdkVersion has installed in your computer.

or modifier the CompileSdkVersion to the version that has been installed in your computer.

In my case:I just installed sdk version 29 in my computer but in the module build.gradle file ,I'm setting the CompilerSdkVersion 28

Both are not matched.

Modifier the build.gradle file CompilerSdkVersion 29 which I installed in my computer

It's working!!!

enter image description here enter image description here

Android Studio: Application Installation Failed

I have faced this issue since I have upgraded the build tools from 26.0.2 to 27.0.3. Reverting back, clean and rebuild solve the issue. Also I have degraded the gradle plugin version from 3.1.3 to 3.0.1 as the latest version was overriding the build tools to latest version.

Couldn't load memtrack module Logcat Error

I had the same error. Creating a new AVD with the appropriate API level solved my problem.

Android Webview gives net::ERR_CACHE_MISS message

Android WebView fix ERR_CACHE_MISS error solution

you just need add one line code <uses-permission android:name="android.permission.INTERNET"/> in your app/src/main/AndroidManifest.xml file as below screenshots shows.

enter image description here

  1. before

enter image description here

  1. after

enter image description here

Code for download video from Youtube on Java, Android

Ref : Youtube Video Download (Android/Java)

private static final HashMap<String, Meta> typeMap = new HashMap<String, Meta>();

initTypeMap(); call first

class Meta {
    public String num;
    public String type;
    public String ext;

    Meta(String num, String ext, String type) {
        this.num = num;
        this.ext = ext;
        this.type = type;

class Video {
    public String ext = "";
    public String type = "";
    public String url = "";

    Video(String ext, String type, String url) {
        this.ext = ext;
        this.type = type;
        this.url = url;

public ArrayList<Video> getStreamingUrisFromYouTubePage(String ytUrl)
        throws IOException {
    if (ytUrl == null) {
        return null;

    // Remove any query params in query string after the watch?v=<vid> in
    // e.g.
    int andIdx = ytUrl.indexOf('&');
    if (andIdx >= 0) {
        ytUrl = ytUrl.substring(0, andIdx);

    // Get the HTML response
    /* String userAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:8.0.1)";*/
   /* HttpClient client = new DefaultHttpClient();
    HttpGet request = new HttpGet(ytUrl);
    HttpResponse response = client.execute(request);*/
    String html = "";
    HttpsURLConnection c = (HttpsURLConnection) new URL(ytUrl).openConnection();
    InputStream in = c.getInputStream();
    BufferedReader reader = new BufferedReader(new InputStreamReader(in));
    StringBuilder str = new StringBuilder();
    String line = null;
    while ((line = reader.readLine()) != null) {
        str.append(line.replace("\\u0026", "&"));
    html = str.toString();

    // Parse the HTML response and extract the streaming URIs
    if (html.contains("verify-age-thumb")) {
        Log.e("Downloader", "YouTube is asking for age verification. We can't handle that sorry.");
        return null;

    if (html.contains("das_captcha")) {
        Log.e("Downloader", "Captcha found, please try with different IP address.");
        return null;

    Pattern p = Pattern.compile("stream_map\":\"(.*?)?\"");
    // Pattern p = Pattern.compile("/stream_map=(.[^&]*?)\"/");
    Matcher m = p.matcher(html);
    List<String> matches = new ArrayList<String>();
    while (m.find()) {

    if (matches.size() != 1) {
        Log.e("Downloader", "Found zero or too many stream maps.");
        return null;

    String urls[] = matches.get(0).split(",");
    HashMap<String, String> foundArray = new HashMap<String, String>();
    for (String ppUrl : urls) {
        String url = URLDecoder.decode(ppUrl, "UTF-8");
        Log.e("URL","URL : "+url);

        Pattern p1 = Pattern.compile("itag=([0-9]+?)[&]");
        Matcher m1 = p1.matcher(url);
        String itag = null;
        if (m1.find()) {
            itag =;

        Pattern p2 = Pattern.compile("signature=(.*?)[&]");
        Matcher m2 = p2.matcher(url);
        String sig = null;
        if (m2.find()) {
            sig =;
        } else {
            Pattern p23 = Pattern.compile("signature&s=(.*?)[&]");
            Matcher m23 = p23.matcher(url);
            if (m23.find()) {
                sig =;

        Pattern p3 = Pattern.compile("url=(.*?)[&]");
        Matcher m3 = p3.matcher(ppUrl);
        String um = null;
        if (m3.find()) {
            um =;

        if (itag != null && sig != null && um != null) {
            Log.e("foundArray","Adding Value");
            foundArray.put(itag, URLDecoder.decode(um, "UTF-8") + "&"
                    + "signature=" + sig);
    Log.e("foundArray","Size : "+foundArray.size());
    if (foundArray.size() == 0) {
        Log.e("Downloader", "Couldn't find any URLs and corresponding signatures");
        return null;

    ArrayList<Video> videos = new ArrayList<Video>();

    for (String format : typeMap.keySet()) {
        Meta meta = typeMap.get(format);

        if (foundArray.containsKey(format)) {
            Video newVideo = new Video(meta.ext, meta.type,
            Log.d("Downloader", "YouTube Video streaming details: ext:" + newVideo.ext
                    + ", type:" + newVideo.type + ", url:" + newVideo.url);

    return videos;

private class YouTubePageStreamUriGetter extends AsyncTask<String, String, ArrayList<Video>> {
    ProgressDialog progressDialog;

    protected void onPreExecute() {
        progressDialog =, "",
                "Connecting to YouTube...", true);

    protected ArrayList<Video> doInBackground(String... params) {
        ArrayList<Video> fVideos = new ArrayList<>();
        String url = params[0];
        try {
            ArrayList<Video> videos = getStreamingUrisFromYouTubePage(url);
            /*                Log.e("Downloader","Size of Video : "+videos.size());*/
            if (videos != null && !videos.isEmpty()) {
                for (Video video : videos)
                    Log.e("Downloader", "ext : " + video.ext);
                    if (video.ext.toLowerCase().contains("mp4") || video.ext.toLowerCase().contains("3gp") || video.ext.toLowerCase().contains("flv") || video.ext.toLowerCase().contains("webm")) {
                        ext = video.ext.toLowerCase();
                        fVideos.add(new Video(video.ext,video.type,video.url));

                return fVideos;
        } catch (Exception e) {
            Log.e("Downloader", "Couldn't get YouTube streaming URL", e);
        Log.e("Downloader", "Couldn't get stream URI for " + url);
        return null;

    protected void onPostExecute(ArrayList<Video> streamingUrl) {
        if (streamingUrl != null) {
            if (!streamingUrl.isEmpty()) {
                //Log.e("Steaming Url", "Value : " + streamingUrl);

                for (int i = 0; i < streamingUrl.size(); i++) {
                    Video fX = streamingUrl.get(i);
                    Log.e("Founded Video", "URL : " + fX.url);
                    Log.e("Founded Video", "TYPE : " + fX.type);
                    Log.e("Founded Video", "EXT : " + fX.ext);
                //new ProgressBack().execute(new String[]{streamingUrl, filename + "." + ext});
public void initTypeMap()
    typeMap.put("13", new Meta("13", "3GP", "Low Quality - 176x144"));
    typeMap.put("17", new Meta("17", "3GP", "Medium Quality - 176x144"));
    typeMap.put("36", new Meta("36", "3GP", "High Quality - 320x240"));
    typeMap.put("5", new Meta("5", "FLV", "Low Quality - 400x226"));
    typeMap.put("6", new Meta("6", "FLV", "Medium Quality - 640x360"));
    typeMap.put("34", new Meta("34", "FLV", "Medium Quality - 640x360"));
    typeMap.put("35", new Meta("35", "FLV", "High Quality - 854x480"));
    typeMap.put("43", new Meta("43", "WEBM", "Low Quality - 640x360"));
    typeMap.put("44", new Meta("44", "WEBM", "Medium Quality - 854x480"));
    typeMap.put("45", new Meta("45", "WEBM", "High Quality - 1280x720"));
    typeMap.put("18", new Meta("18", "MP4", "Medium Quality - 480x360"));
    typeMap.put("22", new Meta("22", "MP4", "High Quality - 1280x720"));
    typeMap.put("37", new Meta("37", "MP4", "High Quality - 1920x1080"));
    typeMap.put("33", new Meta("38", "MP4", "High Quality - 4096x230"));

Edit 2:

Some time This Code Not worked proper

Same-origin policy

problem of Same-origin policy. Essentially, you cannot download this file from because they are different domains. A workaround of this problem is [CORS][1]. 

Ref :

url_encoded_fmt_stream_map // traditional: contains video and audio stream
adaptive_fmts              // DASH: contains video or audio stream

Each of these is a comma separated array of what I would call "stream objects". Each "stream object" will contain values like this

url  // direct HTTP link to a video
itag // code specifying the quality
s    // signature, security measure to counter downloading

Each URL will be encoded so you will need to decode them. Now the tricky part.

YouTube has at least 3 security levels for their videos

unsecured // as expected, you can download these with just the unencoded URL
s         // see below
RTMPE     // uses "rtmpe://" protocol, no known method for these

The RTMPE videos are typically used on official full length movies, and are protected with SWF Verification Type 2. This has been around since 2011 and has yet to be reverse engineered.

The type "s" videos are the most difficult that can actually be downloaded. You will typcially see these on VEVO videos and the like. They start with a signature such as

AA5D05FA7771AD4868BA4C977C3DEAAC620DE020E.0F421820F42978A1F8EAFCDAC4EF507DB5 Then the signature is scrambled with a function like this

function mo(a) {
  a = a.split("");
  a =, 1);
  a =, 32);
  a = lo.IC(a, 1);
  a = lo.wS(a, 77);
  a = lo.IC(a, 3);
  a = lo.wS(a, 77);
  a = lo.IC(a, 3);
  a = lo.wS(a, 44);
  return a.join("")

This function is dynamic, it typically changes every day. To make it more difficult the function is hosted at a URL such as

this introduces the problem of Same-origin policy. Essentially, you cannot download this file from because they are different domains. A workaround of this problem is CORS. With CORS, could add this header


and it would allow the JavaScript to download from Of course they do not do this. A workaround for this workaround is to use a CORS proxy. This is a proxy that responds with the following header to all requests

Access-Control-Allow-Origin: *

So, now that you have proxied your JS file, and used the function to scramble the signature, you can use that in the querystring to download a video.

Android Studio: Gradle - build fails -- Execution failed for task ':dexDebug'

(This might be the wrong thread, as your problem seems more specific, but it's the thread that I found when searching for the issue's keywords)

Despite all good hints, the only thing that helped me, and that I'd like to share just in case, if everything else does not work :

Remove your .gradle directory in your home directory and have it re-build/re-downloaded for you by Android Studio.

Fixed all kinds of weird errors for me that neither were fixable by re-installing Android Studio itself nor the SDK.

Run Android studio emulator on AMD processor

Since Android Studio 3.2 and Android Emulator 27.3.8 - the android emulator is supported by Windows Hypervisor Platform and as stated in the official android developer blog - there is mac support (since OS X v10.10 Yosemite) and windows support (since April 2018 Update). You may find further instructions on the developer blog.

In my opinion, the performance is significantly better than all previous workarounds.

how to drop database in sqlite?

If you want to delete database programatically you can use deleteDatabase from Context class:

deleteDatabase(String name)
Delete an existing private SQLiteDatabase associated with this Context's application package.

Android: How to handle right to left swipe gestures

import android.content.Context
import android.view.GestureDetector
import android.view.GestureDetector.SimpleOnGestureListener
import android.view.MotionEvent
import android.view.View
import android.view.View.OnTouchListener

 * Detects left and right swipes across a view.
class OnSwipeTouchListener(context: Context, onSwipeCallBack: OnSwipeCallBack?) : OnTouchListener {

    private var gestureDetector : GestureDetector
    private var onSwipeCallBack: OnSwipeCallBack?=null

    init {

        gestureDetector = GestureDetector(context, GestureListener())
        this.onSwipeCallBack = onSwipeCallBack!!
    companion object {

        private val SWIPE_DISTANCE_THRESHOLD = 100
        private val SWIPE_VELOCITY_THRESHOLD = 100

   /* fun onSwipeLeft() {}

    fun onSwipeRight() {}*/

    override fun onTouch(v: View, event: MotionEvent): Boolean {

        return gestureDetector.onTouchEvent(event)

    private inner class GestureListener : SimpleOnGestureListener() {

        override fun onDown(e: MotionEvent): Boolean {
            return true

        override fun onFling(eve1: MotionEvent?, eve2: MotionEvent?, velocityX: Float, velocityY: Float): Boolean {
            try {
                if(eve1 != null&& eve2!= null) {
                    val distanceX = eve2?.x - eve1?.x
                    val distanceY = eve2?.y - eve1?.y
                    if (Math.abs(distanceX) > Math.abs(distanceY) && Math.abs(distanceX) > SWIPE_DISTANCE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
                        if (distanceX > 0)
                        return true
            }catch (exception:Exception){

            return false


Android "elevation" not showing a shadow

I've been playing around with shadows on Lollipop for a bit and this is what I've found:

  1. It appears that a parent ViewGroup's bounds cutoff the shadow of its children for some reason; and
  2. shadows set with android:elevation are cutoff by the View's bounds, not the bounds extended through the margin;
  3. the right way to get a child view to show shadow is to set padding on the parent and set android:clipToPadding="false" on that parent.

Here's my suggestion to you based on what I know:

  1. Set your top-level RelativeLayout to have padding equal to the margins you've set on the relative layout that you want to show shadow;
  2. set android:clipToPadding="false" on the same RelativeLayout;
  3. Remove the margin from the RelativeLayout that also has elevation set;
  4. [EDIT] you may also need to set a non-transparent background color on the child layout that needs elevation.

At the end of the day, your top-level relative layout should look like this:

<RelativeLayout xmlns:android=""

The interior relative layout should look like this:

    android:background="[some non-transparent color]"

android: stretch image in imageview to fit screen

I Have used this android:scaleType="fitXY" code in Xml file.

Set drawable size programmatically

i didn't have time to dig why the setBounds() method is not working on bitmap drawable as expected but i have little tweaked @androbean-studio solution to do what setBounds should do...

 * Created by ceph3us on 23.05.17.
 * file belong to
 * this class wraps drawable and forwards draw canvas
 * on it wrapped instance by using its defined bounds
public class WrappedDrawable extends Drawable {

    private final Drawable _drawable;
    protected Drawable getDrawable() {
        return _drawable;

    public WrappedDrawable(Drawable drawable) {
        _drawable = drawable;

    public void setBounds(int left, int top, int right, int bottom) {
        //update bounds to get correctly
        super.setBounds(left, top, right, bottom);
        Drawable drawable = getDrawable();
        if (drawable != null) {
            drawable.setBounds(left, top, right, bottom);

    public void setAlpha(int alpha) {
        Drawable drawable = getDrawable();
        if (drawable != null) {

    public void setColorFilter(ColorFilter colorFilter) {
        Drawable drawable = getDrawable();
        if (drawable != null) {

    public int getOpacity() {
        Drawable drawable = getDrawable();
        return drawable != null
                ? drawable.getOpacity()
                : PixelFormat.UNKNOWN;

    public void draw(Canvas canvas) {
        Drawable drawable = getDrawable();
        if (drawable != null) {

    public int getIntrinsicWidth() {
        Drawable drawable = getDrawable();
        return drawable != null
                ? drawable.getBounds().width()
                : 0;

    public int getIntrinsicHeight() {
        Drawable drawable = getDrawable();
        return drawable != null ?
                : 0;


// get huge drawable 
final Drawable drawable = resources.getDrawable(R.drawable.g_logo);
// create our wrapper           
WrappedDrawable wrappedDrawable = new WrappedDrawable(drawable);
// set bounds on wrapper 
// use wrapped drawable 
Button.setCompoundDrawablesWithIntrinsicBounds(wrappedDrawable ,null, null, null);


before: enter image description here after: enter image description here

How can I pass a Bitmap object from one activity to another

Actually, passing a bitmap as a Parcelable will result in a "JAVA BINDER FAILURE" error. Try passing the bitmap as a byte array and building it for display in the next activity.

I shared my solution here:
how do you pass images (bitmaps) between android activities using bundles?

Unable to execute dex: Multiple dex files define Lcom/myapp/R$array;

I am facing the same problem. The problem I found that I have a library project, in that project's manifest file, there is no targetSdkVersion property. I have added that property under (uses-sdk) tag. Then clean my project. Now my app runs normally.

Bluetooth pairing without user confirmation

BT version 2.0 or less - You should be able to pair/bond using a standard PIN code, entered programmatically e.g. 1234 or 0000. This is not very secure but many BT devices do this.

BT version 2.1 or greater - Mode 4 Secure Simple Pairing "just works" model can be used. It uses elliptical encryption (whatever that is) and is very secure but is open to Man In The Middle attacks. Compared to the old '0000' pin code approach it is light years ahead. This doesn't require any user input.

This is according to the Bluetooth specs but what you can use depends on what verson of the Bluetooth standard your stack supports and what API you have.

Programmatically go back to the previous fragment in the backstack

Add those line to your onBackPressed() Method. popBackStackImmediate() method will get you back to the previous fragment if you have any fragment on back stack `

if(getFragmentManager().getBackStackEntryCount() > 0){


How to implement endless list with RecyclerView?

Here is another approach. It will work with any layout manager.

  1. Make Adapter class abstract
  2. Then create an abstract method in adapter class (eg. load())
  3. In onBindViewHolder check the position if last and call load()
  4. Override the load() function while creating the adapter object in your activity or fragment.
  5. In the overided load function implement your loadmore call

For a detail understanding I wrote a blog post and example project get it here

public abstract class MyAdapter extends RecyclerView.Adapter<ViewHolder>{

        public void onBindViewHolder(ViewHolder holder, int position) {
            //check for last item
            if ((position >= getItemCount() - 1))

        public abstract void load();

public class MainActivity extends AppCompatActivity {
    List<Items> items;
    MyAdapter adapter;

    protected void onCreate(Bundle savedInstanceState) {
    adapter=new MyAdapter(items){
            public void load() {
                //implement your load more here
                Item lastItem=items.get(items.size()-1);

How to animate button in android?

create shake.xml in anim folder

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="" 
                android:interpolator="@anim/cycle" />

and cycle.xml in anim folder

<?xml version="1.0" encoding="utf-8"?>
<cycleInterpolator xmlns:android="" 
    android:cycles="4" />

now add animation on your code

Animation shake = AnimationUtils.loadAnimation(this, R.anim.shake);

If you want vertical animation, change fromXdelta and toXdelta value to fromYdelta and toYdelta value

Android Studio gradle takes too long to build

Enabling Java 8 features caused deadly slow build


 jackOptions {
        enabled true

  compileOptions {
    targetCompatibility 1.8
    sourceCompatibility 1.8

After deleting above lines, it builds in seconds.

There is issue Compiling with Jack takes very long time

Project Manager's Answer

We're aware that build times are an issue with Jack right now. We have improvements in the 2.4 Gradle plugin that should be a significant improvement for incremental builds.

As of now, latest Gradle version i can find is 2.3.0-beta4

Android ImageView Fixing Image Size

In your case you need to

  1. Fix the ImageView's size. You need to use dp unit so that it will look the same in all devices.
  2. Set android:scaleType to fitXY

Below is an example:


For more information regarding ImageView scaleType please refer to the developer website.

How do you import an Eclipse project into Android Studio now?

Stop installing android studio 3.0.1 and go back 2.3.3 ( Stable version) . Check for the stable version and you can find them a lot

All you have to do uninstall and go back to the other version. Yes it asks to create gradle file seperately which is completely new to me!

Failure is the stepping stone for success..

Include .so library in apk in android studio

I've tried the solution presented in the accepted answer and it did not work for me. I wanted to share what DID work for me as it might help someone else. I've found this solution here.

Basically what you need to do is put your .so files inside a a folder named lib (Note: it is not libs and this is not a mistake). It should be in the same structure it should be in the APK file.

In my case it was:
|--|--| files.

So I've made a lib folder and inside it an armeabi folder where I've inserted all the needed .so files. I then zipped the folder into a .zip (the structure inside the zip file is now lib/armeabi/*.so) I renamed the .zip file into armeabi.jar and added the line compile fileTree(dir: 'libs', include: '*.jar') into dependencies {} in the gradle's build file.

This solved my problem in a rather clean way.

How to switch between hide and view password

It is really easy to achieve since the Support Library v24.2.0.

What you need to do is just:

  1. Add the design library to your dependecies

    dependencies {
         compile ""
  2. Use TextInputEditText in conjunction with TextInputLayout


The passwordToggleEnabled attribute will do the job!

  1. In your root layout don't forget to add xmlns:app=""

  2. You can customize your password toggle by using:

app:passwordToggleDrawable - Drawable to use as the password input visibility toggle icon.
app:passwordToggleTint - Icon to use for the password input visibility toggle.
app:passwordToggleTintMode - Blending mode used to apply the background tint.

More details in TextInputLayout documentation.

enter image description here

For AndroidX

  • Replace with

  • Replace with

Is there a way to get the source code from an APK file?

This is an alternative description - just in case someone got stuck with the description above. Follow the steps:

  1. download apktool.bat (or apktool for Linux) and apktool_<version>.jar from
  2. rename the jar file from above to apktool.jar and put both files in the same folder

  3. open a dos box (cmd.exe) and change into that folder; verify that a Java Environment is installed (for Linux check the notes regarding required libraries as well)
  4. Start: apktool decode [apk file]

    Intermediate result: resource files, AndroidManifest.xml

  5. unzip APK file with an unpacker of your choice

    Intermediate result: classes.dex

  6. download and extract from
  7. drag and drop classes.dex onto dex2jar.bat (or enter <path_to>\dex2jar.bat classes.dex in a DOS box; for Linux use

    Intermediate result: classes_dex2jar.jar

  8. unpack classes_dex2jar.jar (might be optional depending on used decompiler)
  9. decompile your class files (e.g. with JD-GUI or DJ Decompiler)

    Result: source code

Note: it is not allowed to decompile third party packages; this guide is intended to recover personal source code from an APK file only; finally, the resulting code will most likely be obfuscated

How to open a second activity on click of button in android app

Button btn = (Button) findViewById(;

btn.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        Intent myIntent = new Intent(MainActivity.this, MainActivity2.class);

The answer for the complete noob from a complete noob: MainActivity is the name of the first activity. MainActivity2 is the name of the second activity. button1 is the I.D of the button in xml for MainActivity Activity.

Error: "Adb connection Error:An existing connection was forcibly closed by the remote host"

I know I'm 4 years late but my answer is for anyone who may not have figured it out. I'm using a Samsung Galaxy S6, what worked for me was:

  1. Disable USB debugging

  2. Disable Developer mode

  3. Unplug the device from the USB cable

  4. Re-enable Developer mode

  5. Re-enable USB debugging

  6. Reconnect the USB cable to your device

It is important you do it in this order as it didn't work until it was done in this order.

adb not finding my device / phone (MacOS X)

Solution specific to Nexus 4 and Nexus 5 for OS X

Got no device listed in the "List of devices attached" when I ran: adb devices


  1. Get the SDK (Latest Version) from
  2. Put developer mode on nexus 4 ( About Phone > Build Number > tap 7 times to enter Dev Mode)
  3. A new menu option will come up in the 'Settings' : { } Developer Options
  4. Make sure you check the following under { } Developer options:
    • USB Debugging : Debug mode when USB is connected (Accept the RSA fingerprint popup)
    • Verify apps over USB : Check apps installed via ADB/ADT for Harmful behavior

Try listing your device from ./adb devices and it should work.

Answer taken from: Any idea why adb does not recognize my nexus 4 on mac

Android ClassNotFoundException: Didn't find class on path

I was having the same issue today. And tried all the above solutions already given but nothing worked for me. Then I spent sometime and I found out the reason. I thought it could save some other developers time I am sharing here as well. The problem was with wrong package name. I was using MVP architecture, and I kept my activities in view package. And I copied the Main class from my other project. This was the catch. In the xml, Main Activity was referring to different Package that was just outer side. The package was not including my view directory (MVP hierarchy level). Then I checked back in manifest as well. The same problem I found there as well. So I provided full path(package name) of my activity(untill MVP' view directory/package there I kept my all activities). This solved my problem. Hope that helps others as well.

Text to speech(TTS)-Android

Try this, its simple : **speakout.xml : **

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android=""
android:orientation="vertical" >
android:text="Speak Out!!!"
android:textStyle="bold" />
android:text="Hi there!!!"
android:text="SPEAK OUT"/>

And Your :

import android.os.Bundle;
import android.speech.tts.TextToSpeech;
import android.speech.tts.TextToSpeech.OnInitListener;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class SpeakOut extends Activity implements OnInitListener {
private TextToSpeech repeatTTS;
Button btnspeakout;
EditText edtTexttoSpeak;

public void onCreate(Bundle savedInstanceState) {
    btnspeakout = (Button) findViewById(;
    edtTexttoSpeak = (EditText) findViewById(;
    repeatTTS = new TextToSpeech(this, this);
    btnspeakout.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            TextToSpeech.QUEUE_FLUSH, null);

    public void onInit(int arg0) {
        // TODO Auto-generated method stub


Android Studio AVD - Emulator: Process finished with exit code 1

Check android studio event log as it could be low storage issue.

emulator: ERROR: Not enough disk space to run AVD 'Nexus_5_API_21'. Exiting...

Problems with Android Fragment back stack

First of all thanks @Arvis for an eye opening explanation.

I prefer different solution to the accepted answer here for this problem. I don't like messing with overriding back behavior any more than absolutely necessary and when I've tried adding and removing fragments on my own without default back stack poping when back button is pressed I found my self in fragment hell :) If you .add f2 over f1 when you remove it f1 won't call any of callback methods like onResume, onStart etc. and that can be very unfortunate.

Anyhow this is how I do it:

Currently on display is only fragment f1.

f1 -> f2

Fragment2 f2 = new Fragment2();

nothing out of the ordinary here. Than in fragment f2 this code takes you to fragment f3.

f2 -> f3

Fragment3 f3 = new Fragment3();
getActivity().getSupportFragmentManager().beginTransaction().replace(, f3).addToBackStack(null).commit();

I'm not sure by reading docs if this should work, this poping transaction method is said to be asynchronous, and maybe a better way would be to call popBackStackImmediate(). But as far I can tell on my devices it's working flawlessly.

The said alternative would be:

final FragmentActivity activity = getActivity();
activity.getSupportFragmentManager().beginTransaction().replace(, f3).addToBackStack(null).commit();

Here there will actually be brief going back to f1 beofre moving on to f3, so a slight glitch there.

This is actually all you have to do, no need to override back stack behavior...

How to use putExtra() and getExtra() for string data

It is very easy to implement intent in Android.. It takes you to move from one activity to another activity,we have to two method putExtra(); and getExtra();Now I am showing you the example..

    Intent intent = new Intent(activity_registration.this, activity_Login.class);
                intent.putExtra("AnyKeyName", Email.getText().toString());  // pass your values and retrieve them in the other Activity using AnyKeyName

Now we have to get the value from AnyKeyName parameter,the below mentioned code will help in doing this

       String data = getIntent().getExtras().getString("AnyKeyName");

We can easily set the receiving value from Intent,wherever we required.

How to change position of Toast in Android?

From the documentation,

Positioning your Toast

A standard toast notification appears near the bottom of the screen, centered horizontally. You can change this position with the setGravity(int, int, int) method. This accepts three parameters: a Gravity constant, an x-position offset, and a y-position offset.

For example, if you decide that the toast should appear in the top-left corner, you can set the gravity like this:

toast.setGravity(Gravity.TOP|Gravity.LEFT, 0, 0);

If you want to nudge the position to the right, increase the value of the second parameter. To nudge it down, increase the value of the last parameter.

How to change option menu icon in the action bar?

Check this out this may work: (in kotlin)

Where does application data file actually stored on android device?

Application Private Data files are stored within <internal_storage>/data/data/<package>

Files being stored in the internal storage can be accessed with openFileOutput() and openFileInput()

When those files are created as MODE_PRIVATE it is not possible to see/access them within another application such as a FileManager.

How to use the ProGuard in Android Studio?

The other answers here are great references on using proguard. However, I haven't seen an issue discussed that I ran into that was a mind bender. After you generate a signed release .apk, it's put in the /release folder in your app but my app had an apk that wasn't in the /release folder. Hence, I spent hours decompiling the wrong apk wondering why my proguard changes were having no affect. Hope this helps someone!

How do I show the number keyboard on an EditText in android?

EditText number1 = (EditText) layout.findViewById(; 

How to hide the title bar for an Activity in XML with existing custom theme

For AppCompat, following solution worked for me:

Add new theme style with no action bar in your styles.xml and set parent="Theme.AppCompat.NoActionBar".

<style name="SplashTheme" parent="Theme.AppCompat.NoActionBar">

    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimary</item>
    <item name="colorAccent">@color/colorAccent</item>
    <item name="android:windowBackground">@color/colorPrimary</item>


Now implement the same theme style to your splash screen activity in androidManifest.xml

        android:theme="@style/SplashTheme"> // apply splash them here 

            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />

Here is result:

enter image description here

EditText onClickListener in Android

Nice topic. Well, I have done so. In XML file:

    android:inputType="none" />

In Java-code:


private View.OnClickListener onOnClickEvent = new View.OnClickListener() {
    public void onClick(View view) {;
private View.OnFocusChangeListener onFocusChangeEvent = new View.OnFocusChangeListener() {
    public void onFocusChange(View v, boolean hasFocus) {
        if (hasFocus)

Detecting touch screen devices with Javascript

I use:

    alert('Touch enabled');

in jQuery mobile 1.0.1

Android ImageView Animation

Don't hard code image bounds. Just use:

RotateAnimation anim = new RotateAnimation( fromAngle, toAngle, imageView.getDrawable().getBounds().width()/2, imageView.getDrawable().getBounds().height()/2);

How to set space between listView Items in Android

@Asahi pretty much hit the nail on the head, but I just wanted to add a bit of XML for anyone maybe floating in here later via google:

<ListView android:id="@+id/MyListView"

For some reason, values such as "10", "10.0", and "10sp" all are rejected by Android for the dividerHeight value. It wants a floating point number and a unit, such as "10.0sp". As @Goofyahead notes, you can also use display-independent pixels for this value (ie, "10dp").

How to get row count in sqlite using Android?

Sooo simple to get row count:

cursor = dbObj.rawQuery("select count(*) from TABLE where COLUMN_NAME = '1' ", null);
String count = cursor.getString(cursor.getColumnIndex(cursor.getColumnName(0)));

Set android shape color programmatically

My Kotlin extension function version based on answers above with Compat:

fun Drawable.overrideColor_Ext(context: Context, colorInt: Int) {
    val muted = this.mutate()
    when (muted) {
        is GradientDrawable -> muted.setColor(ContextCompat.getColor(context, colorInt))
        is ShapeDrawable -> muted.paint.setColor(ContextCompat.getColor(context, colorInt))
        is ColorDrawable -> muted.setColor(ContextCompat.getColor(context, colorInt))
        else -> Log.d("Tag", "Not a valid background type")

Android: alternate layout xml for landscape mode

You can group your specific layout under the correct folder structure as follows.



layout-land-19 // target KitKat

likewise you can create your layouts.

Hope this will help you

How to change Toolbar home icon color

Instead of style changes, just put these two lines of code to your activity.


Android update activity UI from service

I would recommend checking out Otto, an EventBus tailored specifically to Android. Your Activity/UI can listen to events posted on the Bus from the Service, and decouple itself from the backend.

How to create EditText accepts Alphabets only in android?

Try This Method

For Java :

EditText yourEditText = (EditText) findViewById(;
yourEditText.setFilters(new InputFilter[] {
new InputFilter() {
    public CharSequence filter(CharSequence cs, int start,
                int end, Spanned spanned, int dStart, int dEnd) {
        // TODO Auto-generated method stub
        if(cs.equals("")){ // for backspace
             return cs;
        if(cs.toString().matches("[a-zA-Z ]+")){
             return cs;
        return "";

For Kotlin :

 val yourEditText = findViewById<View>( as EditText
    val reges = Regex("^[0-9a-zA-Z ]+$")
    //this will allow user to only write letter and white space
    yourEditText.filters = arrayOf<InputFilter>(
        object : InputFilter {
            override fun filter(
                cs: CharSequence, start: Int,
                end: Int, spanned: Spanned?, dStart: Int, dEnd: Int,
            ): CharSequence? {
                if (cs == "") { // for backspace
                    return cs
                return if (cs.toString().matches(reges)) {
                } else ""

How to resolve "Waiting for Debugger" message?

Not sure if this is what you are looking for, but try putting:


in the application tag in the AndroidManifest.xml

How can I generate an apk that can run without server with react-native?

Hopefully it will help new beginners

Official doc here

If you dont have keystore than use before command else skip

Generating a signing key / Keystore file You can generate a private signing key using keytool. On Windows keytool must be run from C:\Program Files\Java\jdkx.x.x_x\bin.

$ keytool -genkey -v -keystore my-release-key.keystore -alias my-key-alias -keyalg RSA -keysize 2048 -validity 10000

you will get a file like my-release-key.keystore

Setting up gradle variables Place the my-release-key.keystore file under the android/app directory in your project folder. Edit the file android/ and add the following (replace ***** with the correct keystore password, alias and key password), enableAapt2 set false is workaround , as android gradle version 3.0 problem



then add these app/buid.gradle (app)

below default config

signingConfigs {
        release {
            if (project.hasProperty('MYAPP_RELEASE_STORE_FILE')) {
                storeFile file(MYAPP_RELEASE_STORE_FILE)
                storePassword MYAPP_RELEASE_STORE_PASSWORD
                keyAlias MYAPP_RELEASE_KEY_ALIAS
                keyPassword MYAPP_RELEASE_KEY_PASSWORD

and Inside Build type release { }

 signingConfig signingConfigs.release

then simply run this command in android studio terminal Below commands will automate above all answers

if windows

cd android
gradlew assembleRelease

if linux / mac

$ cd android
$ ./gradlew assembleRelease

if you got any error delete all build folder and run command

gradlew clean

than again

gradlew assembleRelease

Where does Android emulator store SQLite database?

For Android Studio 3.5, fount it using instructions here: (View -> Tool Windows -> Device File Explorer -> -> databases

Android: Changing Background-Color of the Activity (Main View)

Try creating a method in your Activity something like...

public void setActivityBackgroundColor(int color) {
    View view = this.getWindow().getDecorView();

Then call it from your OnClickListener passing in whatever colour you want.

How to check if a radiobutton is checked in a radiogroup in Android?

  rgrp.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
        public void onCheckedChanged(RadioGroup radioGroup, int i) {
            switch(i) {
                    Toast.makeText(getApplicationContext()," Car",Toast.LENGTH_LONG).show();
                    Toast.makeText(getApplicationContext()," Bike",Toast.LENGTH_LONG).show();

Disabling of EditText in Android

Set below properties in class:


It will work smoothly as you required.

Android TextView Text not getting wrapped

I know, that in question it is correct, but in my case, the problem was in setting textSize property in 'dp' - I've changed it to 'sp' and it works fine.

How to change Android usb connect mode to charge only?

I have been searching for this for ages on my CM 11 android phone, running kitkat.

Well.. finally I found it. It's hidden in a totally unintuitive location:

  1. Go to settings
  2. Go to storage
  3. Open the menu and choose USB computer connection

Here you can choose between Media Device (MTP), Camera (PTP) and Mass storage (UMS). Turn them all off to get it to charge only.

Sadly, if the option is not there, it is not supported by the phone. This seems to be the case for my HTC One (M7).

How to print all key and values from HashMap in Android?

String text="";

    for (Iterator i = keys.iterator(); i.hasNext() 
           String key = (String);
           String value = (String) map.get(key);
           text+=key + " = " + value;


Why do I get access denied to data folder when using adb?

without rooting the device you can access the files by the following The cmd screenshot:

  1. start the adb using cmd from the platform-tools folder according to your user

    cd C:\Users\YourUserName\AppData\Local\Android\sdk\platform-tools

    it can be in another folder depends on where you installed it.

  2. display the working devices.

    adb devices

    for say the respond os the command is

    List of devices attached
    0123456789ABCDEF     device
  3. write the command

        adb -s 0123456789ABCDEF shell "su"

    it will open in

        root@theDeviceName:/ #

4.Accessing files, list all the files


and so-on chang directory to any where else like the data folder

cd data/data

How to prevent custom views from losing state across screen orientation changes

To augment other answers - if you have multiple custom compound views with the same ID and they are all being restored with the state of the last view on a configuration change, all you need to do is tell the view to only dispatch save/restore events to itself by overriding a couple of methods.

class MyCompoundView : ViewGroup {


    override fun dispatchSaveInstanceState(container: SparseArray<Parcelable>) {

    override fun dispatchRestoreInstanceState(container: SparseArray<Parcelable>) {

For an explanation of what is happening and why this works, see this blog post. Basically your compound view's children's view IDs are shared by each compound view and state restoration gets confused. By only dispatching state for the compound view itself, we prevent their children from getting mixed messages from other compound views.

How to put space character into a string name in XML?

Android doesn't support keeping the spaces at the end of the string in String.xml file so if you want space after string you need to use this unicode in between the words.


It is a unicode space character.

Google Maps Android API v2 - Interactive InfoWindow (like in original android google maps)

Here's my take on the problem. I create AbsoluteLayout overlay which contains Info Window (a regular view with every bit of interactivity and drawing capabilities). Then I start Handler which synchronizes the info window's position with position of point on the map every 16 ms. Sounds crazy, but actually works.

Demo video: (take into account that performance is decreased because of emulator and video recording running simultaneously).

Code of the demo:

An article providing details (in Russian):

Waiting till the async task finish its work

AsyncTask have four methods..

onPreExecute  -- for doing something before calling background task in Async

doInBackground  -- operation/Task to do in Background

onProgressUpdate  -- it is for progress Update

onPostExecute  -- this method calls after asyncTask return from doInBackground.

you can call your work on onPostExecute() it calls after returning from doInBackground()

onPostExecute is what you need to Implement.

ADB not responding. You can wait more,or kill "adb.exe" process manually and click 'Restart'

Check if any service is listening on port 5037, and kill it. You can use lsof for this:

$ lsof -i :5037
$ kill <PID Process>

Then try

$ adb start-server
* daemon not running. starting it now on port 5037 *
* daemon started successfully *

This solved my problem.

Scrollview can host only one direct child

Wrap all the children inside of another LinearLayout with wrap_content for both the width and the height as well as the vertical orientation.

Clear the entire history stack and start a new activity on Android

Try below code,

Intent intent = new Intent(ManageProfileActivity.this, LoginActivity.class);

How to add manifest permission to an application?

Assuming you do not have permissions set from your LogCat error description, here is my contents for my AndroidManifest.xml file that has access to the internet:

<manifest xlmns:android...>
 <uses-permission android:name="android.permission.INTERNET" />
 <application ...

Other than that, you should be fine to download a file from the internet.

How to get current time and date in Android

    long totalSeconds = currentTimeMillis / 1000;
    int currentSecond = (int)totalSeconds % 60;

    long totalMinutes = totalSeconds / 60;
    int currentMinute = (int)totalMinutes % 60;

    long totalHours = totalMinutes / 60;
    int currentHour = (int)totalHours % 12;

    TextView tvTime = findViewById(;
    tvTime.setText((currentHour + OR - TIME YOU ARE FROM GMT) + ":" + currentMinute + ":" + currentSecond);

Android: keeping a background service alive (preventing process death)

I'm working on an app and face issue of killing my service by on app kill. I researched on google and found that I have to make it foreground. following is the code:

public class UpdateLocationAndPrayerTimes extends Service {

 Context context;
public void onCreate() {
    context = this;

public int onStartCommand(Intent intent, int flags, int startId) {

    return START_STICKY;

public void onDestroy() {


public IBinder onBind(Intent intent) {
    return null;

private void StartForground() {
    LocationChangeDetector locationChangeDetector = new LocationChangeDetector(context);
    Notification notification = new NotificationCompat.Builder(this)

    startForeground(101,  notification);


hops that it may helps!!!!

How to get Android GPS location

This code have one problem:

int latitude = (int) (location.getLatitude());
int longitude = (int) (location.getLongitude());

You can change int to double

double latitude = location.getLatitude();
double longitude = location.getLongitude();

Access index of last element in data frame

You want .iloc with double brackets.

import pandas as pd
df = pd.DataFrame({"date": range(10, 64, 8), "not_date": "fools"})
df.index += 17

You give .iloc a list of indexes - specifically the first and last, [0, -1]. That returns a dataframe from which you ask for the 'date' column. ['date'] will give you a series (yuck), and [['date']] will give you a dataframe.

undefined reference to 'vtable for class' constructor

You're declaring a virtual function and not defining it:

virtual void calculateCredits();

Either define it or declare it as:

virtual void calculateCredits() = 0;

Or simply:

virtual void calculateCredits() { };

Read more about vftable:

angular js unknown provider

The problem for me was that there were some new javascript files I created that referenced the service yet Chrome saw only the older version. A CTRL + F5 fixed it for me.

Get HTML inside iframe using jQuery

$('#iframe').load(function() {
    var src = $('#iframe').contents().find("html").html();

Java equivalent to C# extension methods

Extension methods are not just static method and not just convenience syntax sugar, in fact they are quite powerful tool. The main thing there is ability to override different methods based on different generic’s parameters instantiation. This is similar to Haskell’s type classes, and in fact, it looks like they are in C# to support C#’s Monads (i.e. LINQ). Even dropping LINQ syntax, I still don’t know any way to implement similar interfaces in Java.

And I don’t think it is possible to implement them in Java, because of Java’s type erasure semantics of generics parameters.

How do I format my oracle queries so the columns don't wrap?

Never mind, figured it out:

set wrap off
set linesize 3000 -- (or to a sufficiently large value to hold your results page)

Which I found by:

show all

And looking for some option that seemed relevant.

Can we define min-margin and max-margin, max-padding and min-padding in css?

Yes, you can!

Or if not those terms exactly, then at least the next best thing. In 2020 this is now very straightforward using the CSS math functions: min(), max(), and clamp().

A min calculation picks the smallest from a comma separated list of values (of any length). This can be used to define a max-padding or max-margin rule:

padding-right: min(50px, 5%);

A max calculation similarly picks the largest from a comma separated list of values (of any length). This can be used to define a min-padding or min-margin rule:

padding-right: max(15px, 5%);

A clamp takes three values; the minimum, preferred, and maximum values, in that order.

padding-right: clamp(15px, 5%, 50px);

MDN specifies that clamp is actually just shorthand for:


Here is a clamp being used to contain a 25vw margin between the values 100px and 200px:

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;

.container {
  width: 100vw;
  border: 2px dashed red;

.margin {
  width: auto;
  min-width: min-content;
  background-color: lightblue;
  padding: 10px;
  margin-right: clamp(100px, 25vw, 200px);
<div class="container">
  <div class="margin">
    The margin-right on this div uses 25vw as its preferred value,
    100px as its minimum, and 200px as its maximum.

The math functions can be used in all sorts of different scenarios, even potentially obscure ones like scaling font-size - they are not just for controlling margin and padding. Check out the full list of use cases at the MDN links at the top of this post.

Here is the caniuse list of browser support. Coverage is generally very good, including almost all modern browsers - with the exception, it appears, of some secondary mobile browsers although have not tested this myself.

MongoDB and "joins"

The first example you link to shows how MongoDB references behave much like lazy loading not like a join. There isn't a query there that's happening on both collections, rather you query one and then you lookup items from another collection by reference.

How can I unstage my files again after making a local commit?

Lets say you want to unstage changes upto n commits,

Where commit hashes are as follows:

  • h1
  • h2 ...
  • hn
  • hn+1

Then run the following command:
git reset hn

Now the HEAD will be at hn+1. Changes from h1 to hn will be unstaged.

'ng' is not recognized as an internal or external command, operable program or batch file

note: you may lose values once system restarts.

You can also add system environment variables without Admin rights in Windows 10.

Go to Control panel --> user accounts

Change my environment variables

environment variables --> select **Path** and click edit

click **New** and add path to it

now don't restart, close any opened cmd or powershell, reopen cmd and test by ng version command if you see this it is confirmed working fine.

ng version --> Angular cli

hope this helps

How do I split a string by a multi-character delimiter in C#?

You can use String.Replace() to replace your desired split string with a character that does not occur in the string and then use String.Split on that character to split the resultant string for the same effect.

Date difference in years using C#

I hope the link below helps

MSDN - DateTime.Subtract.Method (DateTime)

There's even examples for C# there. Just simply click the C# language tab.

Good luck

Sass Nesting for :hover does not work

You can easily debug such things when you go through the generated CSS. In this case the pseudo-selector after conversion has to be attached to the class. Which is not the case. Use "&".

.class {
    &:hover {

How to add a footer in ListView?

The activity in which you want to add listview footer and i have also generate an event on listview footer click.

  public class MainActivity extends Activity

        protected void onCreate(Bundle savedInstanceState)


            ListView  list_of_f = (ListView) findViewById(;

            LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            View view = inflater.inflate(R.layout.web_view, null);  // i have open a webview on the listview footer

            RelativeLayout  layoutFooter = (RelativeLayout) view.findViewById(;





<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android=""
    android:background="@drawable/bg" >

        android:background="@drawable/dept_nav" />

        android:listSelector="@android:color/transparent" >


What are allowed characters in cookies?

There is another interesting issue with IE and Edge. Cookies that have names with more than 1 period seem to be silently dropped. So This works:


while this will get dropped

How to comment in Vim's config files: ".vimrc"?

You can add comments in Vim's configuration file by either:

" brief descriptiion of command


"" commended command

Taken from here

How to include route handlers in multiple files in Express?

And build yet more on the previous answer, this version of routes/index.js will ignore any files not ending in .js (and itself)

var fs = require('fs');

module.exports = function(app) {
    fs.readdirSync(__dirname).forEach(function(file) {
        if (file === "index.js" || file.substr(file.lastIndexOf('.') + 1) !== 'js')
        var name = file.substr(0, file.indexOf('.'));
        require('./' + name)(app);

Stop setInterval

You need to set the return value of setInterval to a variable within the scope of the click handler, then use clearInterval() like this:

var interval = null;
    interval = setInterval(updateDiv,3000);

function updateDiv(){
        url: 'getContent.php',
        success: function(data){
        error: function(){
            clearInterval(interval); // stop the interval
            $('.square').html('<span style="color:red">Connection problems</span>');

The model backing the <Database> context has changed since the database was created

Here's some information from Scott Gu's Blog posted by Jeff on what's actually taking place:

For those who are seeing this exception:

"The model backing the 'Production' context has changed since the database was created. Either manually delete/update the database, or call Database.SetInitializer with an IDatabaseInitializer instance."

Here is what is going on and what to do about it:

When a model is first created, we run a DatabaseInitializer to do things like create the database if it's not there or add seed data. The default DatabaseInitializer tries to compare the database schema needed to use the model with a hash of the schema stored in an EdmMetadata table that is created with a database (when Code First is the one creating the database). Existing databases won’t have the EdmMetadata table and so won’t have the hash…and the implementation today will throw if that table is missing. We'll work on changing this behavior before we ship the fial version since it is the default. Until then, existing databases do not generally need any database initializer so it can be turned off for your context type by calling:



Best way to combine two or more byte arrays in C#

    /// <summary>
    /// Combine two Arrays with offset and count
    /// </summary>
    /// <param name="src1"></param>
    /// <param name="offset1"></param>
    /// <param name="count1"></param>
    /// <param name="src2"></param>
    /// <param name="offset2"></param>
    /// <param name="count2"></param>
    /// <returns></returns>
    public static T[] Combine<T>(this T[] src1, int offset1, int count1, T[] src2, int offset2, int count2) 
        => Enumerable.Range(0, count1 + count2).Select(a => (a < count1) ? src1[offset1 + a] : src2[offset2 + a - count1]).ToArray();

How do I know the script file name in a Bash script?

To answer Chris Conway, on Linux (at least) you would do this:

echo $(basename $(readlink -nf $0))

readlink prints out the value of a symbolic link. If it isn't a symbolic link, it prints the file name. -n tells it to not print a newline. -f tells it to follow the link completely (if a symbolic link was a link to another link, it would resolve that one as well).

Android - shadow on text?

 <style name="WhiteTextWithShadow" parent="@android:style/TextAppearance">
    <item name="android:shadowDx">1</item>
    <item name="android:shadowDy">1</item>
    <item name="android:shadowRadius">1</item>
    <item name="android:shadowColor">@android:color/black</item>
    <item name="android:textColor">@android:color/white</item>

then use as

            tools:text="Today, May 21"

See last changes in svn

If you have a working copy then svn status will help.

svn status -u -v

The --show-updates (-u) option contacts the repository and adds information about things that are out of date.

UIScrollView scroll to bottom programmatically

Solution to scroll to last item of a table View :

Swift 3 :

if self.items.count > 0 {
        self.tableView.scrollToRow(at:  IndexPath.init(row: self.items.count - 1, section: 0), at: UITableViewScrollPosition.bottom, animated: true)

How to compare two java objects

You need to provide your own implementation of equals() in MyClass.

public boolean equals(Object other) {
    if (!(other instanceof MyClass)) {
        return false;

    MyClass that = (MyClass) other;

    // Custom equality check here.
    return this.field1.equals(that.field1)
        && this.field2.equals(that.field2);

You should also override hashCode() if there's any chance of your objects being used in a hash table. A reasonable implementation would be to combine the hash codes of the object's fields with something like:

public int hashCode() {
    int hashCode = 1;

    hashCode = hashCode * 37 + this.field1.hashCode();
    hashCode = hashCode * 37 + this.field2.hashCode();

    return hashCode;

See this question for more details on implementing a hash function.

"Fatal error: Unable to find local grunt." when running "grunt" command

I had the same issue today on windows 32 bit,with node 0.10.25, and grunt 0.4.5.

I followed dongho's answer, with just few extra steps. here are the steps I used to solve the error:

1) create your package.json

$ npm init

2) install grunt for this project, this will be installed under node_modules/. --save-dev will add this module to devDependency in your package.json

$ npm install grunt --save-dev

3) then create gruntfile.js , with a sample code like this:

module.exports = function(grunt) {

    jshint: {
      files: ['Gruntfile.js', 'src/**/*.js', 'test/**/*.js'],
      options: {
        globals: {
          jQuery: true
    watch: {
      files: ['<%= jshint.files %>'],
      tasks: ['jshint']


  grunt.registerTask('default', ['jshint']);


here, src/**/*.js and test/**/*.js should be the paths to actual JS files you are using in your project

4) run npm install grunt-contrib-jshint --save-dev

5) run npm install grunt-contrib-watch --save-dev

6) run $ grunt

Note: when you require common package like concat, uglify etc, you need to add those modules via npm install, just the way we installed jshint and watch in step 4 & 5

What's Mongoose error Cast to ObjectId failed for value XXX at path "_id"?

Detecting and Correcting the ObjectID Error

I stumbled into this problem when trying to delete an item using mongoose and got the same error. After looking over the return string, I found there were some extra spaces inside the returned string which caused the error for me. So, I applied a few of the answers provided here to detect the erroneous id then remove the extra spaces from the string. Here is the code that worked for me to finally resolve the issue.

const mongoose = require("mongoose");
mongoose.set('useFindAndModify', false);  //was set due to DeprecationWarning: Mongoose: `findOneAndUpdate()` and `findOneAndDelete()` without the `useFindAndModify`"/delete", function(req, res){
  let checkedItem = req.body.deleteItem;
  if (!mongoose.Types.ObjectId.isValid(checkedItem)) {
    checkedItem = checkedItem.replace(/\s/g, '');

  Item.findByIdAndRemove(checkedItem, function(err) {
    if (!err) {
      console.log("Successfully Deleted " + checkedItem);

This worked for me and I assume if other items start to appear in the return string they can be removed in a similar way.

I hope this helps.

Disable Proximity Sensor during call

Unfortunately my proximity sensor doesn't work, too (always returns 0.0 cm). I found the way, but not easy one: you need to root your phone, install XPOSED framework and Sensor Disabler ( You can mock proximity sensor return value in the app. (e.g. always return 2.0 cm). Then your display will be always on during the call.

Does a `+` in a URL scheme/host/path represent a space?

use encodeURIComponent function to fix url, it works on Browser and node.js

res.redirect("/signin?email="+encodeURIComponent("[email protected]"));

> encodeURIComponent("")

generating variable names on fly in python

Though I don't see much point, here it is:

for i in xrange(0, len(prices)):
    exec("price%d = %s" % (i + 1, repr(prices[i])));

Git: Installing Git in PATH with GitHub client for Windows

If you are using vscode's terminal then it might not work even if you do the environment variable thing, test by typing git

Restart vscode, it should work.

How to remove close button on the jQuery UI dialog?

For the deactivating the class, the short code:


may be used.

How can I make the contents of a fixed element scrollable only when it exceeds the height of the viewport?

For your purpose, you can just use

position: absolute;
top: 0%;

and it still be resizable, scrollable and responsive.

Possible to make labels appear when hovering over a point in matplotlib?

showing object information in matplotlib statusbar

enter image description here


  • no extra libraries needed
  • clean plot
  • no overlap of labels and artists
  • supports multi artist labeling
  • can handle artists from different plotting calls (like scatter, plot, add_patch)
  • code in library style


### imports
import matplotlib as mpl
import matplotlib.pylab as plt
import numpy as np

class StatusbarHoverManager:
    Manage hover information for mpl.axes.Axes object based on appearing

    ax : mpl.axes.Axes
        subplot to show status information
    artists : list of mpl.artist.Artist
        elements on the subplot, which react to mouse over
    labels : list (list of strings) or strings
        each element on the top level corresponds to an artist.
        if the artist has items
        (i.e. second return value of contains() has key 'ind'),
        the element has to be of type list.
        otherwise the element if of type string
    cid : to reconnect motion_notify_event
    def __init__(self, ax):
        assert isinstance(ax, mpl.axes.Axes)

        def hover(event):
            if event.inaxes != ax:
            info = 'x={:.2f}, y={:.2f}'.format(event.xdata, event.ydata)
            ax.format_coord = lambda x, y: info
        cid = ax.figure.canvas.mpl_connect("motion_notify_event", hover) = ax
        self.cid = cid
        self.artists = []
        self.labels = []

    def add_artist_labels(self, artist, label):
        if isinstance(artist, list):
            assert len(artist) == 1
            artist = artist[0]

        self.artists += [artist]
        self.labels += [label]

        def hover(event):
            if event.inaxes !=
            info = 'x={:.2f}, y={:.2f}'.format(event.xdata, event.ydata)
            for aa, artist in enumerate(self.artists):
                cont, dct = artist.contains(event)
                if not cont:
                inds = dct.get('ind')
                if inds is not None:  # artist contains items
                    for ii in inds:
                        lbl = self.labels[aa][ii]
                        info += ';   artist [{:d}, {:d}]: {:}'.format(
                            aa, ii, lbl)
                    lbl = self.labels[aa]
                    info += ';   artist [{:d}]: {:}'.format(aa, lbl)
   = lambda x, y: info
        self.cid =
            "motion_notify_event", hover)

def demo_StatusbarHoverManager():
    fig, ax = plt.subplots()
    shm = StatusbarHoverManager(ax)

    poly = mpl.patches.Polygon(
        [[0,0], [3, 5], [5, 4], [6,1]], closed=True, color='green', zorder=0)
    artist = ax.add_patch(poly)
    shm.add_artist_labels(artist, 'polygon')

    artist = ax.scatter([2.5, 1, 2, 3], [6, 1, 1, 7], c='blue', s=10**2)
    lbls = ['point ' + str(ii) for ii in range(4)]
    shm.add_artist_labels(artist, lbls)

    artist = ax.plot(
        [0, 0, 1, 5, 3], [0, 1, 1, 0, 2], marker='o', color='red')
    lbls = ['segment ' + str(ii) for ii in range(5)]
    shm.add_artist_labels(artist, lbls)

# --- main
if __name__== "__main__":

XSS filtering function in PHP

I have a similar problem. I need users to submit html content to a profile page with a great WYSIWYG editor (Redactorjs!), i wrote the following function to clean the submitted html:

    <?php function filterxss($str) {
//Initialize DOM:
$dom = new DOMDocument();
//Load content and add UTF8 hint:
$dom->loadHTML('<meta http-equiv="content-type" content="text/html; charset=utf-8">'.$str);
//Array holds allowed attributes and validation rules:
$check = array('src'=>'#(http://[^\s]+(?=\.(jpe?g|png|gif)))#i','href'=>'|^http(s)?://[a-z0-9-]+(.[a-z0-9-]+)*(:[0-9]+)?(/.*)?$|i');
//Loop all elements:
foreach($dom->getElementsByTagName('*') as $node){
    for($i = $node->attributes->length -1; $i >= 0; $i--){
        //Get the attribute:
        $attribute = $node->attributes->item($i);
        //Check if attribute is allowed:
        if( in_array($attribute->name,array_keys($check))) {
            //Validate by regex:    
            if(!preg_match($check[$attribute->name],$attribute->value)) { 
                //No match? Remove the attribute
            //Not allowed? Remove the attribute:
var_dump($dom->saveHTML()); } ?>

The $check array holds all the allowed attributes and validation rules. Maybe this is useful for some of you. I haven't tested is yet, so tips are welcome

#1055 - Expression of SELECT list is not in GROUP BY clause and contains nonaggregated column this is incompatible with sql_mode=only_full_group_by

Base ond defualt config of 5.7.5 ONLY_FULL_GROUP_BY You should use all the not aggregate column in your group by

select libelle,credit_initial,disponible_v,sum(montant) as montant 
FROM fiche,annee,type 
where type.id_type=annee.id_type 
and annee.id_annee=fiche.id_annee 
and annee = year(current_timestamp) 
GROUP BY libelle,credit_initial,disponible_v order by libelle asc

push() a two-dimensional array

Iterating over two dimensions means you'll need to check over two dimensions.

assuming you're starting with:

var myArray = [
]; //don't forget your semi-colons

You want to expand this two-dimensional array to become:

var myArray = [

Which means you need to understand what the difference is.

Start with the outer array:

var myArray = [

If you want to make this array longer, you need to check that it's the correct length, and add more inner arrays to make up the difference:

var i,
rows = 8;
myArray = [...]; //see first example above
for (i = 0; i < rows; i += 1) {
    //check if the index exists in the outer array
    if (!(i in myArray)) {
        //if it doesn't exist, we need another array to fill

The next step requires iterating over every column in every array, we'll build on the original code:

var i,
rows = 8;
cols = 7; //adding columns in this time
myArray = [...]; //see first example above
for (i = 0; i < rows; i += 1) {
    //check if the index exists in the outer array (row)
    if (!(i in myArray)) {
        //if it doesn't exist, we need another array to fill
        myArray[i] = [];
    row = myArray[i];
    for (j = 0; j < cols; j += 1) {
        //check if the index exists in the inner array (column)
        if (!(i in row)) {
            //if it doesn't exist, we need to fill it with `0`
            row[j] = 0;

How can I check if a file exists in Perl?

#!/usr/bin/perl -w

$fileToLocate = '/whatever/path/for/file/you/are/searching/MyFile.txt';
if (-e $fileToLocate) {
    print "File is present";

Javascript ES6 export const vs export let

In ES6, imports are live read-only views on exported-values. As a result, when you do import a from "somemodule";, you cannot assign to a no matter how you declare a in the module.

However, since imported variables are live views, they do change according to the "raw" exported variable in exports. Consider the following code (borrowed from the reference article below):

//------ lib.js ------
export let counter = 3;
export function incCounter() {

//------ main1.js ------
import { counter, incCounter } from './lib';

// The imported value `counter` is live
console.log(counter); // 3
console.log(counter); // 4

// The imported value can’t be changed
counter++; // TypeError

As you can see, the difference really lies in lib.js, not main1.js.

To summarize:

  • You cannot assign to import-ed variables, no matter how you declare the corresponding variables in the module.
  • The traditional let-vs-const semantics applies to the declared variable in the module.
    • If the variable is declared const, it cannot be reassigned or rebound in anywhere.
    • If the variable is declared let, it can only be reassigned in the module (but not the user). If it is changed, the import-ed variable changes accordingly.


Chrome Dev Tools - Modify javascript and reload

The Resource Override extension allows you to do exactly that:

  • create a file rule for the url you want to replace
  • edit the js/css/etc in the extension
  • reload as often as you want :)

Java: How to insert CLOB into oracle database

Take a look at the LobBasicSample for an example to use CLOB, BLOB, NLOB datatypes.

How to change the style of the title attribute inside an anchor tag?

I have found the answer here:

my own code goes like this, I have changed the attribute name, if you maintain the title name for the attribute you end up having two popups for the same text, another change is that my text on hovering displays underneath the exposed text.

.tags {
  display: inline;
  position: relative;

.tags:hover:after {
  background: #333;
  background: rgba(0, 0, 0, .8);
  border-radius: 5px;
  bottom: -34px;
  color: #fff;
  content: attr(gloss);
  left: 20%;
  padding: 5px 15px;
  position: absolute;
  z-index: 98;
  width: 350px;

.tags:hover:before {
  border: solid;
  border-color: #333 transparent;
  border-width: 0 6px 6px 6px;
  bottom: -4px;
  content: "";
  left: 50%;
  position: absolute;
  z-index: 99;
<a class="tags" gloss="Text shown on hovering">Exposed text</a>

Input from the keyboard in command line application

Here is simple example of taking input from user on console based application: You can use readLine(). Take input from console for first number then press enter. After that take input for second number as shown in the image below:

func solveMefirst(firstNo: Int , secondNo: Int) -> Int {
    return firstNo + secondNo

let num1 = readLine()
let num2 = readLine()

var IntNum1 = Int(num1!)
var IntNum2 = Int(num2!)

let sum = solveMefirst(IntNum1!, secondNo: IntNum2!)


How to use BeginInvoke C#

Action is a Type of Delegate provided by the .NET framework. The Action points to a method with no parameters and does not return a value.

() => is lambda expression syntax. Lambda expressions are not of Type Delegate. Invoke requires Delegate so Action can be used to wrap the lambda expression and provide the expected Type to Invoke()

Invoke causes said Action to execute on the thread that created the Control's window handle. Changing threads is often necessary to avoid Exceptions. For example, if one tries to set the Rtf property on a RichTextBox when an Invoke is necessary, without first calling Invoke, then a Cross-thread operation not valid exception will be thrown. Check Control.InvokeRequired before calling Invoke.

BeginInvoke is the Asynchronous version of Invoke. Asynchronous means the thread will not block the caller as opposed to a synchronous call which is blocking.

Does C# have an equivalent to JavaScript's encodeURIComponent()?

System.Uri.EscapeUriString() didn't seem to do anything, but System.Uri.EscapeDataString() worked for me.

Gson: Is there an easier way to serialize a map


The default Gson implementation of Map serialization uses toString() on the key:

Gson gson = new GsonBuilder()
Map<Point, String> original = new HashMap<>();
original.put(new Point(1, 2), "a");
original.put(new Point(3, 4), "b");

Will give:

  "java.awt.Point[x\u003d1,y\u003d2]": "a",
  "java.awt.Point[x\u003d3,y\u003d4]": "b"

Using enableComplexMapKeySerialization

If you want the Map Key to be serialized according to default Gson rules you can use enableComplexMapKeySerialization. This will return an array of arrays of key-value pairs:

Gson gson = new GsonBuilder().enableComplexMapKeySerialization()
Map<Point, String> original = new HashMap<>();
original.put(new Point(1, 2), "a");
original.put(new Point(3, 4), "b");

Will return:

      "x": 1,
      "y": 2
      "x": 3,
      "y": 4

More details can be found here.

XML Parser for C

On Windows, it's native with Win32 api...

Update a table using JOIN in SQL Server?

Another approach would be to use MERGE

  ;WITH cteTable1(CalculatedColumn, CommonField)
    select CalculatedColumn, CommonField from Table1 Where BatchNo = '110'
  MERGE cteTable1 AS target
    USING (select "Calculated Column", "Common Field" FROM dbo.Table2) AS source ("Calculated Column", "Common Field")
    ON (target.CommonField = source."Common Field")
        UPDATE SET target.CalculatedColumn = source."Calculated Column";

-Merge is part of the SQL Standard

-Also I'm pretty sure inner join updates are non deterministic.. Similar question here where the answer talks about that

When should I use UNSIGNED and SIGNED INT in MySQL?

Use UNSIGNED for non-negative integers.


declare @p varbinary(max)
set @p = 0x
declare @local table (col text)

SELECT   @p = @p + 0x3B + CONVERT(varbinary(100), Email)
 FROM tbCarsList
 where email <> ''
 group by email
 order by email

 set @p = substring(@p, 2, 100000)

 insert @local values(cast(@p as varchar(max)))
 select DATALENGTH(col) as collen, col from @local

result collen > 8000, length col value is more than 8000 chars

Removing elements by class name?

You can use this syntax: node.parentNode

For example:

someNode = document.getElementById("someId");

How to name Dockerfiles

I think you should have a directory per container with a Dockerfile (no extension) in it. For example:


When you build just use the directory name, Docker will find the Dockerfile. e.g:

docker build -f ./db .

How to assign execute permission to a .sh file in windows to be executed in linux

This is not possible. Linux permissions and windows permissions do not translate. They are machine specific. It would be a security hole to allow permissions to be set on files before they even arrive on the target system.

angular2 manually firing click event on particular element

This worked for me:

<button #loginButton ...

and inside the controller:

@ViewChild('loginButton') loginButton;

Finding elements not in a list

You are reassigning item to the values in z as you iterate through z. So the first time in your for loop, item = 0, next item = 1, etc... You are never checking one list against the other.

To do it very explicitly:

>>> item = [0,1,2,3,4,5,6,7,8,9]
>>> z = [0,1,2,3,4,5,6,7]
>>> for elem in item:
...   if elem not in z:
...     print elem

How do we count rows using older versions of Hibernate (~2009)?

If you are using Hibernate 5+, then query will be modified as

Long count = session.createQuery("select count(1) from  Book")

Or if you Need TypedQuery

Long count = session.createQuery("select count(1) from  Book",Long.class)

How to split a string into an array of characters in Python?

split() inbuilt function will only separate the value on the basis of certain condition but in the single word, it cannot fulfill the condition. So, it can be solved with the help of list(). It internally calls the Array and it will store the value on the basis of an array.


a = "bottle"
a.split() // will only return the word but not split the every single char.

a = "bottle"
list(a) // will separate ['b','o','t','t','l','e']

Declare and assign multiple string variables at the same time

string a = "", b = a , c = a, d = a, e = a, f =a;

Ruby: How to get the first character of a string

You can use Ruby's open classes to make your code much more readable. For instance, this:

class String
  def initial

will allow you to use the initial method on any string. So if you have the following variables:

last_name = "Smith"
first_name = "John"

Then you can get the initials very cleanly and readably:

puts first_name.initial   # prints J
puts last_name.initial    # prints S

The other method mentioned here doesn't work on Ruby 1.8 (not that you should be using 1.8 anymore anyway!--but when this answer was posted it was still quite common):

puts 'Smith'[0]           # prints 83

Of course, if you're not doing it on a regular basis, then defining the method might be overkill, and you could just do it directly:

puts last_name[0,1] 

Bootstrap 3 navbar active li not changing background-color

In my own bootstrap.css that I load after the bootstrap.min.css only that, switch of the background image with !important works for me:

.navbar-nav li a:hover, .navbar-nav > .active > a {
  color: #fff !important;

  background-color:#f4511e !important;
  background-image: none !important;

Intersect Two Lists in C#

You need to first transform data1, in your case by calling ToString() on each element.

Use this if you want to return strings.

List<int> data1 = new List<int> {1,2,3,4,5};
List<string> data2 = new List<string>{"6","3"};

var newData = data1.Select(i => i.ToString()).Intersect(data2);

Use this if you want to return integers.

List<int> data1 = new List<int> {1,2,3,4,5};
List<string> data2 = new List<string>{"6","3"};

var newData = data1.Intersect(data2.Select(s => int.Parse(s));

Note that this will throw an exception if not all strings are numbers. So you could do the following first to check:

int temp;
if(data2.All(s => int.TryParse(s, out temp)))
    // All data2 strings are int's

What's the best practice to "git clone" into an existing folder?

This is the Best of all methods i came across

Clone just the repository's .git folder (excluding files as they are already in existing-dir) into an empty temporary directory

  1. git clone --no-checkout repo-path-to-clone existing-dir/existing-dir.tmp //might want --no-hardlinks for cloning local repo

Move the .git folder to the directory with the files. This makes existing-dir a git repo.

  1. mv existing-dir/existing-dir.tmp/.git existing-dir/

Delete the temporary directory

  1. rmdir existing-dir/existing-dir.tmp

  2. cd existing-dir

Git thinks all files are deleted, this reverts the state of the repo to HEAD.

WARNING: any local changes to the files will be lost.

  1. git reset --mixed HEAD

call a static method inside a class?

This is a very late response, but adds some detail on the previous answers

When it comes to calling static methods in PHP from another static method on the same class, it is important to differentiate between self and the class name.

Take for instance this code:

class static_test_class {
    public static function test() {
        echo "Original class\n";

    public static function run($use_self) {
        if($use_self) {
        } else {
            $class = get_called_class();

class extended_static_test_class extends static_test_class {
    public static function test() {
        echo "Extended class\n";


The output of this code is:

Original class

Extended class

This is because self refers to the class the code is in, rather than the class of the code it is being called from.

If you want to use a method defined on a class which inherits the original class, you need to use something like:

$class = get_called_class();


TEXT is a data-type for text based input. On the other hand, you have BLOB and CLOB which are more suitable for data storage (images, etc) due to their larger capacity limits (4GB for example).

As for the difference between BLOB and CLOB, I believe CLOB has character encoding associated with it, which implies it can be suited well for very large amounts of text.

BLOB and CLOB data can take a long time to retrieve, relative to how quick data from a TEXT field can be retrieved. So, use only what you need.

How to make HTML element resizable using pure Javascript?

I have created a function that recieve an id of an html element and adds a border to it's right side the function is general and just recieves an id so you can copy it as it is and it will work

var myoffset;_x000D_
function resizeE(elem){_x000D_
    var borderDiv = document.createElement("div");_x000D_
    borderDiv.className = "border";_x000D_
    borderDiv.addEventListener("mousedown",myresize = function myrsize(e) {_x000D_
     myoffset = e.clientX - (document.getElementById(elem).offsetLeft + parseInt(window.getComputedStyle(document.getElementById(elem)).getPropertyValue("width")));_x000D_
     document.addEventListener("mousemove",mouseMove = function mousMove(e) {_x000D_
      document.getElementById(elem).style.width = `${e.clientX -  myoffset - document.getElementById(elem).offsetLeft}px`;_x000D_
function mouseUp() {_x000D_
    document.removeEventListener("mousemove", mouseMove);_x000D_
function load() _x000D_
.border {_x000D_
  position: absolute;_x000D_
  cursor: e-resize;_x000D_
  width: 9px;_x000D_
  right: -5px;_x000D_
  top: 0;_x000D_
  height: 100%;_x000D_
#resizeableDiv {_x000D_
  width: 30vw;_x000D_
  height: 30vh;_x000D_
  background-color: #84f4c6;_x000D_
  position: relative;_x000D_
#anotherresizeableDiv {_x000D_
  width: 30vw;_x000D_
  height: 30vh;_x000D_
  background-color: #9394f4;_x000D_
  position: relative;_x000D_
#anotherresizeableDiv1 {_x000D_
  width: 30vw;_x000D_
  height: 30vh;_x000D_
  background-color: #43f4f4;_x000D_
  position: relative;_x000D_
#anotherresizeableDiv1 .border{_x000D_
  background-color: black;_x000D_
#anotherresizeableDiv .border{_x000D_
  width: 30px;_x000D_
  right: -200px;_x000D_
  background-color: green;_x000D_
<body onload="load()">_x000D_
  <div id="resizeableDiv">change my size with the east border</div>_x000D_
  <div id="anotherresizeableDiv1">with visible border</div>_x000D_
  <div id="anotherresizeableDiv">with editted outside border</div>_x000D_

resizeE("resizeableDiv"); //this calls a function that does the magic to the id inserted

Apple Cover-flow effect using jQuery or other library?

Not sure if you're talking about Coverflow (scroll through images) or Quicklook (preview files in lightbox), try editing your question.

Here's some JS Coverflow implementations:

How to copy folders to docker image from Dockerfile?

Use ADD (docs)

The ADD command can accept as a <src> parameter:

  1. A folder within the build folder (the same folder as your Dockerfile). You would then add a line in your Dockerfile like this:
ADD folder /path/inside/your/container


  1. A single-file archive anywhere in your host filesystem. To create an archive use the command:
tar -cvzf newArchive.tar.gz /path/to/your/folder

You would then add a line to your Dockerfile like this:

ADD /path/to/archive/newArchive.tar.gz  /path/inside/your/container


  • ADD will automatically extract your archive.
  • presence/absence of trailing slashes is important, see the linked docs

How to deal with a slow SecureRandom generator?

You should be able to select the faster-but-slightly-less-secure /dev/urandom on Linux using:

However, this doesn't work with Java 5 and later (Java Bug 6202721). The suggested work-around is to use:

(note the extra /./)

Excel VBA function to print an array to the workbook

A more elegant way is to assign the whole array at once:

Sub PrintArray(Data, SheetName, StartRow, StartCol)

    Dim Rng As Range

    With Sheets(SheetName)
        Set Rng = .Range(.Cells(StartRow, StartCol), _
            .Cells(UBound(Data, 1) - LBound(Data, 1) + StartRow, _
            UBound(Data, 2) - LBound(Data, 2) + StartCol))
    End With
    Rng.Value2 = Data

End Sub

But watch out: it only works up to a size of about 8,000 cells. Then Excel throws a strange error. The maximum size isn't fixed and differs very much from Excel installation to Excel installation.

Find row number of matching value

For your first method change ws.Range("A") to ws.Range("A:A") which will search the entirety of column a, like so:

Sub Find_Bingo()

        Dim wb As Workbook
        Dim ws As Worksheet
        Dim FoundCell As Range
        Set wb = ActiveWorkbook
        Set ws = ActiveSheet

            Const WHAT_TO_FIND As String = "Bingo"

            Set FoundCell = ws.Range("A:A").Find(What:=WHAT_TO_FIND)
            If Not FoundCell Is Nothing Then
                MsgBox (WHAT_TO_FIND & " found in row: " & FoundCell.Row)
                MsgBox (WHAT_TO_FIND & " not found")
            End If
End Sub

For your second method, you are using Bingo as a variable instead of a string literal. This is a good example of why I add Option Explicit to the top of all of my code modules, as when you try to run the code it will direct you to this "variable" which is undefined and not intended to be a variable at all.

Additionally, when you are using With...End With you need a period . before you reference Cells, so Cells should be .Cells. This mimics the normal qualifying behavior (i.e. Sheet1.Cells.Find..)

Change Bingo to "Bingo" and change Cells to .Cells

With Sheet1
        Set FoundCell = .Cells.Find(What:="Bingo", After:=.Cells(1, 1), _
        LookIn:=xlValues, lookat:=xlPart, SearchOrder:=xlByRows, _
        SearchDirection:=xlNext, MatchCase:=False, SearchFormat:=False)
    End With

If Not FoundCell Is Nothing Then
        MsgBox ("""Bingo"" found in row " & FoundCell.Row)
        MsgBox ("Bingo not found")
End If


In my

With Sheet1
End With

The Sheet1 refers to a worksheet's code name, not the name of the worksheet itself. For example, say I open a new blank Excel workbook. The default worksheet is just Sheet1. I can refer to that in code either with the code name of Sheet1 or I can refer to it with the index of Sheets("Sheet1"). The advantage to using a codename is that it does not change if you change the name of the worksheet.

Continuing this example, let's say I renamed Sheet1 to Data. Using Sheet1 would continue to work, as the code name doesn't change, but now using Sheets("Sheet1") would return an error and that syntax must be updated to the new name of the sheet, so it would need to be Sheets("Data").

In the VB Editor you would see something like this:

code object explorer example

Notice how, even though I changed the name to Data, there is still a Sheet1 to the left. That is what I mean by codename.

The Data worksheet can be referenced in two ways:

Debug.Print Sheet1.Name
Debug.Print Sheets("Data").Name

Both should return Data

More discussion on worksheet code names can be found here.

How to use template module with different set of variables?

- name: copy vhosts
  template: src=site-vhost.conf dest=/etc/apache2/sites-enabled/{{ item }}.conf
    - somehost.local
    - otherhost.local
  notify: restart apache

IMPORTANT: Note that an item does not have to be just a string, it can be an object with as many properties as you like, so that way you can pass any number of variables.

In the template I have:

<VirtualHost *:80>
    ServerAdmin [email protected]
    ServerName {{ item }}
    DocumentRoot /vagrant/public

    ErrorLog ${APACHE_LOG_DIR}/error-{{ item }}.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined


Display PNG image as response to jQuery AJAX request

You'll need to send the image back base64 encoded, look at this:

Then in your ajax call change the success function to this:

$('.div_imagetranscrits').html('<img src="data:image/png;base64,' + data + '" />');

copy from one database to another using oracle sql developer - connection failed

The copy command is a SQL*Plus command (not a SQL Developer command). If you have your tnsname entries setup for SID1 and SID2 (e.g. try a tnsping), you should be able to execute your command.

Another assumption is that table1 has the same columns as the message_table (and the columns have only the following data types: CHAR, DATE, LONG, NUMBER or VARCHAR2). Also, with an insert command, you would need to be concerned about primary keys (e.g. that you are not inserting duplicate records).

I tried a variation of your command as follows in SQL*Plus (with no errors):

copy from scott/tiger@db1 to scott/tiger@db2 create new_emp using select * from emp;

After I executed the above statement, I also truncate the new_emp table and executed this command:

copy from scott/tiger@db1 to scott/tiger@db2 insert new_emp using select * from emp;

With SQL Developer, you could do the following to perform a similar approach to copying objects:

  1. On the tool bar, select Tools>Database copy.

  2. Identify source and destination connections with the copy options you would like. enter image description here

  3. For object type, select table(s). enter image description here

  4. Specify the specific table(s) (e.g. table1). enter image description here

The copy command approach is old and its features are not being updated with the release of new data types. There are a number of more current approaches to this like Oracle's data pump (even for tables).

Use YAML with variables

Rails / ruby frameworks are able to do some templating ... it's frequently used to load env variables ...

# fooz.yml
    bar: <%= $ENV[:some_var] %>

No idea if this works for javascript frameworks as I think that YML format is superset of json and it depends on what reads the yml file for you.

If you can use the template like that or the << >> or the {{ }} styles depending on your reader, after that you just ...

In another yml file ...

# boo.yml

  fooz: foo

Which allows you to basically insert a variable as your reference that original file each time which is dynamically set. When reading I was also seeing you can create or open YML files as objects on the fly for several languages which allows you to create a file & chain write a series of YML files or just have them all statically pointing to the dynamically created one.

String comparison in bash. [[: not found

How you are running your script? If you did with

$ sh myscript

you should try:

$ bash myscript

or, if the script is executable:

$ ./myscript

sh and bash are two different shells. While in the first case you are passing your script as an argument to the sh interpreter, in the second case you decide on the very first line which interpreter will be used.

Convert Existing Eclipse Project to Maven Project

I was having the same issue and wanted to Mavenise entire eclipse workspace containing around 60 Eclipse projects. Doing so manually required a lot of time and alternate options were not that viable. To solve the issue I finally created a project called eclipse-to-maven on github. As eclipse doesn't have all necessary information about the dependencies, it does the following:

  • Based on <classpathentry/> XML elements in .classpath file, it creates the dependencies on another project, identifies the library jar file and based on its name (for instance jakarta-oro-2.0.8.jar) identifies its version. Currently artifactId and groupId are same as I couldn't find something which could return me the Maven groupId of the dependency based on artifactId. Though this is not a perfect solution it provides a good ground to speed up Mavenisation.

  • It moves all source folders according to Maven convention (like src/main/java)

  • As Eclipse projects having names with spaces are difficult to deal on Linux/Unix environment, it renames them as well with names without spaces.

  • Resultant pom.xml files contain the dependencies and basic pom structure. You have to add required Maven plugins manually.

Best Way to View Generated Source of Webpage?

In the elements tab, right click the html node > copy > copy element - then paste into an editor.

As has been mentioned above, once the source has been converted into a DOM tree, the original source no longer exists in the browser. Any changes you make will be to the DOM, not the source.

However, you can parse the modified DOM back into HTML, letting you see the "generated source".

  1. In Chrome, open the developer tools and click the elements tab.
  2. Right click the HTML element.
  3. Choose copy > copy element.
  4. Paste into an editor.

You can now see the current DOM as an HTML page.

This is not the full DOM

Note that the DOM cannot be fully represented by an HTML document. This is because the DOM has many more properties than the HTML has attributes. However this will do a reasonable job.

Apache Proxy: No protocol handler was valid

For my Apache2.4 + php5-fpm installation to start working, I needed to activate the following Apache modules:

sudo a2enmod proxy
sudo a2enmod proxy_fcgi

No need for proxy_http, and this is what sends all .php files straight to php5-fpm:

<FilesMatch \.php$>
    SetHandler "proxy:unix:/var/run/php5-fpm.sock|fcgi://localhost"

How to modify a global variable within a function in bash?

What you are doing, you are executing test1


in a sub-shell( child shell ) and Child shells cannot modify anything in parent.

You can find it in bash manual

Please Check: Things results in a subshell here

[Vue warn]: Property or method is not defined on the instance but referenced during render

If you're experiencing this problem, check to make sure you don't have

methods: {


computed: {

declared twice

What is the use of <<<EOD in PHP?

there are four types of strings available in php. They are single quotes ('), double quotes (") and Nowdoc (<<<'EOD') and heredoc(<<<EOD) strings

you can use both single quotes and double quotes inside heredoc string. Variables will be expanded just as double quotes.

nowdoc strings will not expand variables just like single quotes.


How to read a file line-by-line into a list?

According to Python's Methods of File Objects, the simplest way to convert a text file into a list is:

with open('file.txt') as f:
    my_list = list(f)
    # my_list = [x.rstrip() for x in f] # remove line breaks

If you just need to iterate over the text file lines, you can use:

with open('file.txt') as f:
    for line in f:

Old answer:

Using with and readlines() :

with open('file.txt') as f:
    lines = f.readlines()

If you don't care about closing the file, this one-liner works:

lines = open('file.txt').readlines()

The traditional way:

f = open('file.txt') # Open file on read mode
lines = # List with stripped line-breaks
f.close() # Close file

How to serialize a JObject without the formatting?

You can also do the following;

string json = myJObject.ToString(Newtonsoft.Json.Formatting.None);

How do I change the UUID of a virtual disk?

Even though this question asked is old, note that changing a UUID on a virtual HDD in a windows system will make windows treat it as a not activated machine (as it notices the disk change) and will ask for reactivation !

How to remove elements/nodes from angular.js array

Just a slight expansion on the 'angular' solution. I wanted to exclude an item based on it's numeric id, so the ! approach doesn't work. The more general solution which should work for { name: 'ted' } or { id: 42 } is:

mycollection = $filter('filter')(myCollection, { id: theId }, function (obj, test) { 
                                                             return obj !== test; });

Call two functions from same onclick

You can create a single function that calls both of those, and then use it in the event.

function myFunction(){

And then, for the button:

<input id="btn" type="button" value="click" onclick="myFunction();"/>

Python: How exactly can you take a string, split it, reverse it and join it back together again?

I was asked to do so without using any inbuilt function. So I wrote three functions for these tasks. Here is the code-

def string_to_list(string):
'''function takes actual string and put each word of string in a list'''
list_ = []
x = 0 #Here x tracks the starting of word while y look after the end of word.
for y in range(len(string)):
    if string[y]==" ":
        x = y+1
    elif y==len(string)-1:
return list_

def list_to_reverse(list_):
'''Function takes the list of words and reverses that list'''
reversed_list = []
for element in list_[::-1]:
return reversed_list

def list_to_string(list_):
'''This function takes the list and put all the elements of the list to a string with 
space as a separator'''
final_string = str()
for element in list_:
    final_string += str(element) + " "
return final_string

text = "I love India"
list_ = string_to_list(text)
reverse_list = list_to_reverse(list_)
final_string = list_to_string(reverse_list)
print("Input is - {}; Output is - {}".format(text, final_string))
#op= Input is - I love India; Output is - India love I 

Please remember, This is one of a simpler solution. This can be optimized so try that. Thank you!

Inline JavaScript onclick function

Based on the answer that @Mukund Kumar gave here's a version that passes the event argument to the anonymous function:

<a href="#" onClick="(function(e){
    alert('Hey i am calling');
    return false;
})(arguments[0]);return false;">click here</a>

Cannot add a project to a Tomcat server in Eclipse

  1. Right-click on project
  2. Go to properties => project factes
  3. Click on runtime tab
  4. Check the box of the server
  5. Then ok

Close the eclipse and start the server you will able to see and run the project.

Python handling socket.error: [Errno 104] Connection reset by peer

You can try to add some time.sleep calls to your code.

It seems like the server side limits the amount of requests per timeunit (hour, day, second) as a security issue. You need to guess how many (maybe using another script with a counter?) and adjust your script to not surpass this limit.

In order to avoid your code from crashing, try to catch this error with try .. except around the urllib2 calls.

Java Project: Failed to load ApplicationContext

I faced this issue, and that is when a Bean (@Bean) was not instantiated properly as it was not given the correct parameters in my test class.

"Use the new keyword if hiding was intended" warning

@wdavo is correct. The same is also true for functions.

If you override a base function, like Update, then in your subclass you need:

new void Update()
  //do stufff

Without the new at the start of the function decleration you will get the warning flag.

Laravel 4 Eloquent Query Using WHERE with OR AND OR?

Incase you're looping the OR conditions, you don't need the the second $query->where from the other posts (actually I don't think you need in general, you can just use orWhere in the nested where if easier)

$attributes = ['first'=>'a','second'=>'b'];

$query->where(function ($query) use ($attributes) 
    foreach ($attributes as $key=>value)
        //you can use orWhere the first time, doesn't need to be ->where

Postgresql column reference "id" is ambiguous

  FROM v_groups vg INNER JOIN  
       people2v_groups p2vg ON = p2vg.v_group_id
 WHERE p2vg.people_id = 0;

Efficiency of Java "Double Brace Initialization"?

Taking the following test class:

public class Test {
  public void test() {
    Set<String> flavors = new HashSet<String>() {{
        add("butter pecan");

and then decompiling the class file, I see:

public class Test {
  public void test() {
    java.util.Set flavors = new HashSet() {

      final Test this$0;

        this$0 = Test.this;
        add("butter pecan");

This doesn't look terribly inefficient to me. If I were worried about performance for something like this, I'd profile it. And your question #2 is answered by the above code: You're inside an implicit constructor (and instance initializer) for your inner class, so "this" refers to this inner class.

Yes, this syntax is obscure, but a comment can clarify obscure syntax usage. To clarify the syntax, most people are familiar with a static initializer block (JLS 8.7 Static Initializers):

public class Sample1 {
    private static final String someVar;
    static {
        String temp = null;
        ..... // block of code setting temp
        someVar = temp;

You can also use a similar syntax (without the word "static") for constructor usage (JLS 8.6 Instance Initializers), although I have never seen this used in production code. This is much less commonly known.

public class Sample2 {
    private final String someVar;

    // This is an instance initializer
        String temp = null;
        ..... // block of code setting temp
        someVar = temp;

If you don't have a default constructor, then the block of code between { and } is turned into a constructor by the compiler. With this in mind, unravel the double brace code:

public void test() {
  Set<String> flavors = new HashSet<String>() {
        add("butter pecan");

The block of code between the inner-most braces is turned into a constructor by the compiler. The outer-most braces delimit the anonymous inner class. To take this the final step of making everything non-anonymous:

public void test() {
  Set<String> flavors = new MyHashSet();

class MyHashSet extends HashSet<String>() {
    public MyHashSet() {
        add("butter pecan");

For initialization purposes, I'd say there is no overhead whatsoever (or so small that it can be neglected). However, every use of flavors will go not against HashSet but instead against MyHashSet. There is probably a small (and quite possibly negligible) overhead to this. But again, before I worried about it, I would profile it.

Again, to your question #2, the above code is the logical and explicit equivalent of double brace initialization, and it makes it obvious where "this" refers: To the inner class that extends HashSet.

If you have questions about the details of instance initializers, check out the details in the JLS documentation.

Is there a limit to the length of a GET request?

Not in the RFC, no, but there are practical limits.

The HTTP protocol does not place any a priori limit on the length of a URI. Servers MUST be able to handle the URI of any resource they serve, and SHOULD be able to handle URIs of unbounded length if they provide GET-based forms that could generate such URIs. A server SHOULD return 414 (Request-URI Too Long) status if a URI is longer than the server can handle (see section 10.4.15).

Note: Servers should be cautious about depending on URI lengths above 255 bytes, because some older client or proxy implementations may not properly support these lengths.

Convert an NSURL to an NSString

You can use any one way

NSString *string=[NSString stringWithFormat:@"%@",url1];


NSString *str=[url1 absoluteString];

NSLog(@"string :: %@",string);

string :: file:///var/containers/Bundle/Application/E2D7570B-D5A6-45A0-8EAAA1F7476071FE/

NSLog(@"str :: %@", str);

str :: file:///var/containers/Bundle/Application/E2D7570B-D5A6-45A0-8EAA-A1F7476071FE/

Python DNS module import error

On Debian 7 Wheezy, I had to do:

pip install --upgrade dnspython

even if python-dns package was installed.

How can I convert an integer to a hexadecimal string in C?

Interesting that these answers utilize printf like it is a given. printf converts the integer to a Hexadecimal string value.

// void prntnum(unsigned long n, int base, char sign, char *outbuf)
// unsigned long num = number to be printed
// int base        = number base for conversion;  decimal=10,hex=16
// char sign       = signed or unsigned output
// char *outbuf   = buffer to hold the output number

void prntnum(unsigned long n, int base, char sign, char *outbuf)

    int i = 12;
    int j = 0;

        outbuf[i] = "0123456789ABCDEF"[num % base];
        n = num/base;
    }while( num > 0);

    if(sign != ' '){
        outbuf[0] = sign;

    while( ++i < 13){
       outbuf[j++] = outbuf[i];

    outbuf[j] = 0;


Test a weekly cron job

The solution I am using is as follows:

  1. Edit crontab(use command :crontab -e) to run the job as frequently as needed (every 1 minute or 5 minutes)
  2. Modify the shell script which should be executed using cron to prints the output into some file (e.g: echo "Working fine" >>
  3. Check the output.txt file using the command : tail -f output.txt, which will print the latest additions into this file, and thus you can track the execution of the script

How to use the curl command in PowerShell?

In Powershell 3.0 and above there is both a Invoke-WebRequest and Invoke-RestMethod. Curl is actually an alias of Invoke-WebRequest in PoSH. I think using native Powershell would be much more appropriate than curl, but it's up to you :).

Invoke-WebRequest MSDN docs are here:

Invoke-RestMethod MSDN docs are here:

Is there an R function for finding the index of an element in a vector?

The function match works on vectors:

x <- sample(1:10)
# [1]  4  5  9  3  8  1  6 10  7  2
# [1] 1 5

match only returns the first encounter of a match, as you requested. It returns the position in the second argument of the values in the first argument.

For multiple matching, %in% is the way to go:

x <- sample(1:4,10,replace=TRUE)
# [1] 3 4 3 3 2 3 1 1 2 2
which(x %in% c(2,4))
# [1]  2  5  9 10

%in% returns a logical vector as long as the first argument, with a TRUE if that value can be found in the second argument and a FALSE otherwise.

how to show confirmation alert with three buttons 'Yes' 'No' and 'Cancel' as it shows in MS Word

This cannot be done with the native javascript dialog box, but a lot of javascript libraries include more flexible dialogs. You can use something like jQuery UI's dialog box for this.

See also these very similar questions:

Here's an example, as demonstrated in this jsFiddle:

    <script type="text/javascript" src=""></script>
    <script type="text/javascript" src=""></script>
    <link rel="stylesheet" type="text/css" href="/css/normalize.css">
    <link rel="stylesheet" type="text/css" href="/css/result-light.css">
    <link rel="stylesheet" type="text/css" href="">
    <a class="checked" href="">Click here</a>
    <script type="text/javascript">

        $(function() {
            $('.checked').click(function(e) {
                var dialog = $('<p>Are you sure?</p>').dialog({
                    buttons: {
                        "Yes": function() {alert('you chose yes');},
                        "No":  function() {alert('you chose no');},
                        "Cancel":  function() {
                            alert('you chose cancel');


JUnit Eclipse Plugin?

You do not need to install or update any software for the JUnit. it is the part of Java Development tools and comes with almost most of the latest versions in Eclipse.

Go to your project. Right click onto that->Select buildpath->add library->select JUnit from the list ->select the version you want to work with-> done

build you project again to see the errors gone:)

selenium get current url after loading a page

It's been a little while since I coded with selenium, but your code looks ok to me. One thing to note is that if the element is not found, but the timeout is passed, I think the code will continue to execute. So you can do something like this:

boolean exists = driver.findElements(By.xpath("//*[@id='someID']")).size() != 0

What does the above boolean return? And are you sure selenium actually navigates to the expected page? (That may sound like a silly question but are you actually watching the pages change... selenium can be run remotely you know...)

Choosing a jQuery datagrid plugin?

A good plugin that I have used before is DataTables.

Passing event and argument to v-on in Vue.js

You can also do something like this...

<input @input="myHandler('foo', 'bar', ...arguments)">

Evan You himself recommended this technique in one post on Vue forum. In general some events may emit more than one argument. Also as documentation states internal variable $event is meant for passing original DOM event.

Giving graphs a subtitle in matplotlib

The solution that worked for me is:

  • use suptitle() for the actual title
  • use title() for the subtitle and adjust it using the optional parameter y:
    import matplotlib.pyplot as plt
            some code here
    plt.title('My subtitle',fontsize=16)
    plt.suptitle('My title',fontsize=24, y=1)

There can be some nasty overlap between the two pieces of text. You can fix this by fiddling with the value of y until you get it right.

xpath find if node exists

Try the following expression: boolean(path-to-node)

How do I get the browser scroll position in jQuery?

It's better to use $(window).scroll() rather than $('#Eframe').on("mousewheel")

$('#Eframe').on("mousewheel") will not trigger if people manually scroll using up and down arrows on the scroll bar or grabbing and dragging the scroll bar itself.

    var scrollPos = $(document).scrollTop();

If #Eframe is an element with overflow:scroll on it and you want it's scroll position. I think this should work (I haven't tested it though).

    var scrollPos = $('#Eframe').scrollTop();

How can I make my website's background transparent without making the content (images & text) transparent too?

Make the background image transparent/semi-transparent. If it's a solid coloured background just create a 1px by 1px image in fireworks or whatever and adjust its opacity...

Random number from a range in a Bash Script

You can get the random number through urandom

head -200 /dev/urandom | cksum


3310670062 52870

To retrieve the one part of the above number.

head -200 /dev/urandom | cksum | cut -f1 -d " "

Then the output is


To meet your requirement,

head -200 /dev/urandom |cksum | cut -f1 -d " " | awk '{print $1%63000+2001}'

REST, HTTP DELETE and parameters

No, it is not RESTful. The only reason why you should be putting a verb (force_delete) into the URI is if you would need to overload GET/POST methods in an environment where PUT/DELETE methods are not available. Judging from your use of the DELETE method, this is not the case.

HTTP error code 409/Conflict should be used for situations where there is a conflict which prevents the RESTful service to perform the operation, but there is still a chance that the user might be able to resolve the conflict himself. A pre-deletion confirmation (where there are no real conflicts which would prevent deletion) is not a conflict per se, as nothing prevents the API from performing the requested operation.

As Alex said (I don't know who downvoted him, he is correct), this should be handled in the UI, because a RESTful service as such just processes requests and should be therefore stateless (i.e. it must not rely on confirmations by holding any server-side information about of a request).

Two examples how to do this in UI would be to:

  • pre-HTML5:* show a JS confirmation dialog to the user, and send the request only if the user confirms it
  • HTML5:* use a form with action DELETE where the form would contain only "Confirm" and "Cancel" buttons ("Confirm" would be the submit button)

(*) Please note that HTML versions prior to 5 do not support PUT and DELETE HTTP methods natively, however most modern browsers can do these two methods via AJAX calls. See this thread for details about cross-browser support.

Update (based on additional investigation and discussions):

The scenario where the service would require the force_delete=true flag to be present violates the uniform interface as defined in Roy Fielding's dissertation. Also, as per HTTP RFC, the DELETE method may be overridden on the origin server (client), implying that this is not done on the target server (service).

So once the service receives a DELETE request, it should process it without needing any additional confirmation (regardless if the service actually performs the operation).

Difference between Destroy and Delete

Yes there is a major difference between the two methods Use delete_all if you want records to be deleted quickly without model callbacks being called

If you care about your models callbacks then use destroy_all

From the official docs

destroy_all(conditions = nil) public

Destroys the records matching conditions by instantiating each record and calling its destroy method. Each object’s callbacks are executed (including :dependent association options and before_destroy/after_destroy Observer methods). Returns the collection of objects that were destroyed; each will be frozen, to reflect that no changes should be made (since they can’t be persisted).

Note: Instantiation, callback execution, and deletion of each record can be time consuming when you’re removing many records at once. It generates at least one SQL DELETE query per record (or possibly more, to enforce your callbacks). If you want to delete many rows quickly, without concern for their associations or callbacks, use delete_all instead.

jackson deserialization json to java-objects

 JsonNode node = mapper.readValue("[{\"id\":\"value11\",\"name\": \"value12\",\"qty\":\"value13\"},"

 System.out.println("id : "+node.findValues("id").get(0).asText());

this also done the trick.

The performance impact of using instanceof in Java

instanceof is probably going to be more costly than a simple equals in most real world implementations (that is, the ones where instanceof is really needed, and you can't just solve it by overriding a common method, like every beginner textbook as well as Demian above suggest).

Why is that? Because what is probably going to happen is that you have several interfaces, that provide some functionality (let's say, interfaces x, y and z), and some objects to manipulate that may (or not) implement one of those interfaces... but not directly. Say, for instance, I have:

w extends x

A implements w

B extends A

C extends B, implements y

D extends C, implements z

Suppose I am processing an instance of D, the object d. Computing (d instanceof x) requires to take d.getClass(), loop through the interfaces it implements to know whether one is == to x, and if not do so again recursively for all of their ancestors... In our case, if you do a breadth first exploration of that tree, yields at least 8 comparisons, supposing y and z don't extend anything...

The complexity of a real-world derivation tree is likely to be higher. In some cases, the JIT can optimize most of it away, if it is able to resolve in advance d as being, in all possible cases, an instance of something that extends x. Realistically, however, you are going to go through that tree traversal most of the time.

If that becomes an issue, I would suggest using a handler map instead, linking the concrete class of the object to a closure that does the handling. It removes the tree traversal phase in favor of a direct mapping. However, beware that if you have set a handler for C.class, my object d above will not be recognized.

here are my 2 cents, I hope they help...

Fatal Error: Allowed Memory Size of 134217728 Bytes Exhausted (CodeIgniter + XML-RPC)

If you're running a WHM-powered VPS (virtual private server) you may find that you do not have permissions to edit PHP.INI directly; the system must do it. In the WHM host control panel, go to Service ConfigurationPHP Configuration Editor and modify memory_limit:

Updating memory_limit on WHM 11.48.4

How to determine if object is in array

I would use a generic iterator of property/value over the array. No jQuery required.

arr = [{prop1: 'val1', prop2: 'val2'}, {prop1: 'val3', prop2: 'val4'}];

objectPropInArray(arr, 'prop1', 'val3'); // <-- returns true

function objectPropInArray(list, prop, val) {
  if (list.length > 0 ) {
    for (i in list) {
      if (list[i][prop] === val) {
        return true;
  return false;  

iconv - Detected an illegal character in input string

If you used the accepted answer, however, you will still receive the PHP Notice if a character in your input string cannot be transliterated:

$cp1252 = '';

for ($i = 128; $i < 256; $i++) {
    $cp1252 .= chr($i);

echo iconv("cp1252", "utf-8//TRANSLIT", $cp1252);

PHP Notice:  iconv(): Detected an illegal character in input string in CP1252.php on line 8

Notice: iconv(): Detected an illegal character in input string in CP1252.php on line 8

So you should use IGNORE, which will ignore what can't be transliterated:

echo iconv("cp1252", "utf-8//IGNORE", $cp1252);

Disable Pinch Zoom on Mobile Web

Try with min-width property. Let me explain you. Assume a device with screen width of 400px (for an instance). When you zoom in, the fonts gets larger and larger. But boxes and divs remains with same width. If you use min-width, you can avoid decreasing your div and box.

Neither user 10102 nor current process has android.permission.READ_PHONE_STATE

I was experiencing this problem on Samsung devices (fine on others). like zyamys suggested in his/her comment, I added the manifest.permission line but in addition to rather than instead of the original line, so:

<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.Manifest.permission.READ_PHONE_STATE" />

I'm targeting API 22, so don't need to explicitly ask for permissions.

Add a Progress Bar in WebView

You can try this code into your activity

    private void startWebView(WebView webView,String url) {
 webView.setWebViewClient(new WebViewClient() {
            ProgressDialog progressDialog;

            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                return false;

            public void onPageStarted(WebView view, String url, Bitmap favicon) {
                super.onPageStarted(view, url, favicon);

            public void onLoadResource (WebView view, String url) {

                    if (progressDialog == null) {
                        progressDialog = new ProgressDialog(SponceredDetailsActivity.this);

            public void onPageFinished(WebView view, String url) {
                    if (progressDialog.isShowing()) {
                        progressDialog = null;

                }catch(Exception exception){



Call this method using this way:

startWebView(web_view,"Your Url");

Sometimes if URL is dead it will redirected and it will come to onLoadResource() before onPageFinished method. For this reason progress bar will not dismis. To solve this issue see my this Answer.

Thanks :)

How to stick a footer to bottom in css?

I agree with Luke Vo's solution. I thought it would better to omit justify-content: space-between; from layout-wrapper and add margin-top: auto; to footer.

You wouldn't want your body to be hanging in the middle and only have footer pushed to the bottom.

This approach addresses any content extending beyond the viewport.


For SQL Developer

You have to execute it manually


After that if you execute any procedure with DBMS_OUTPUT.PUT_LINE('info'); or directly .

This will print the line

And please don't try to add this


inside the definition of function and procedure, it will not compile and will not work.

C# list.Orderby descending

look it this piece of code from my project

I'm trying to re-order the list based on a property inside my model,

 allEmployees = new List<Employee>(allEmployees.OrderByDescending(employee => employee.Name));

but I faced a problem when a small and capital letters exist, so to solve it, I used the string comparer.

allEmployees.OrderBy(employee => employee.Name,StringComparer.CurrentCultureIgnoreCase)

ActiveRecord: size vs count

The following strategies all make a call to the database to perform a COUNT(*) query.



records = Model.all

The following is not as efficient as it will load all records from the database into Ruby, which then counts the size of the collection.

records = Model.all

If your models have associations and you want to find the number of belonging objects (e.g. @customer.orders.size), you can avoid database queries (disk reads). Use a counter cache and Rails will keep the cache value up to date, and return that value in response to the size method.

Checking if jquery is loaded using Javascript

something is not right

Well, you are using jQuery to check for the presence of jQuery. If jQuery isn't loaded then $() won't even run at all and your callback won't execute, unless you're using another library and that library happens to share the same $() syntax.

Remove your $(document).ready() (use something like window.onload instead):

window.onload = function() {
    if (window.jQuery) {  
        // jQuery is loaded  
    } else {
        // jQuery is not loaded
        alert("Doesn't Work");

Select2() is not a function

you might be referring two jquery scripts which is giving the above error.

How to extract base URL from a string in JavaScript?

You can use below codes for get different parameters of Current URL

alert("document.URL : "+document.URL);
alert("document.location.href : "+document.location.href);
alert("document.location.origin : "+document.location.origin);
alert("document.location.hostname : "+document.location.hostname);
alert(" : ";
alert("document.location.pathname : "+document.location.pathname);

Install NuGet via PowerShell script

  1. Run Powershell with Admin rights
  2. Type the below PowerShell security protocol command for TLS12:
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

Selecting empty text input using jQuery

You could also do it by defining your own selector:

    textboxEmpty: function(el){
        return $(el).val() === "";

And then access them like this:

alert($(':text:textboxEmpty').length); //alerts the number of text boxes in your selection

ERROR: SQLSTATE[HY000] [2002] No connection could be made because the target machine actively refused it

Delete the following files from the directory:


This solved my problem.

The specified DSN contains an architecture mismatch between the Driver and Application. JAVA

If you are connecting from a 64-bit platform using a 32-bit driver, then run the executable C:\Windows\SysWOW64\odbcad32.exe and create the DSN. It will work.

What is the correct target for the JAVA_HOME environment variable for a Linux OpenJDK Debian-based distribution?

The standard Ubuntu install seems to put the various Java versions in /usr/lib/jvm. The javac, java you find in your path will softlink to this.

There's no issue with installing your own Java version anywhere you like, as long as you set the JAVA_HOME environment variable and make sure to have the new Java bin on your path.

A simple way to do this is to have the Java home exist as a softlink, so that if you want to upgrade or switch versions you only have to change the directory that this points to - e.g.:

/usr/bin/java --> /opt/jdk/bin/java,

/opt/jdk --> /opt/jdk1.6.011

SQL Server - boolean literal?

You can use 'True' or 'False' strings for simulate bolean type data.

Select *
From <table>
Where <columna> = 'True'

I think this way maybe slow than just put 1 because it's resolved with Convert_implicit function.

EditText underline below text property

Use android:backgroundTint="" in your EditText xml layout.

For api<21 you can use AppCompatEditText from support library thenapp:backgroundTint=""

Getting "Skipping JaCoCo execution due to missing execution data file" upon executing JaCoCo

In my case, the prepare agent had a different destFile in configuration, but accordingly the report had to be configured with a dataFile, but this configuration was missing. Once the dataFile was added, it started working fine.

What is a bus error?

mmap minimal POSIX 7 example

"Bus error" happens when the kernel sends SIGBUS to a process.

A minimal example that produces it because ftruncate was forgotten:

#include <fcntl.h> /* O_ constants */
#include <unistd.h> /* ftruncate */
#include <sys/mman.h> /* mmap */

int main() {
    int fd;
    int *map;
    int size = sizeof(int);
    char *name = "/a";

    fd = shm_open(name, O_RDWR | O_CREAT, (mode_t)0600);
    /* THIS is the cause of the problem. */
    /*ftruncate(fd, size);*/
    map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    /* This is what generates the SIGBUS. */
    *map = 0;

Run with:

gcc -std=c99 main.c -lrt

Tested in Ubuntu 14.04.

POSIX describes SIGBUS as:

Access to an undefined portion of a memory object.

The mmap spec says that:

References within the address range starting at pa and continuing for len bytes to whole pages following the end of an object shall result in delivery of a SIGBUS signal.

And shm_open says that it generates objects of size 0:

The shared memory object has a size of zero.

So at *map = 0 we are touching past the end of the allocated object.

Unaligned stack memory accesses in ARMv8 aarch64

This was mentioned at: What is a bus error? for SPARC, but here I will provide a more reproducible example.

All you need is a freestanding aarch64 program:

.global _start
    /* misalign the stack out of 16-bit boundary */
    add sp, sp, #-4
    /* access the stack */
    ldr w0, [sp]

    /* exit syscall in case SIGBUS does not happen */
    mov x0, 0
    mov x8, 93
    svc 0

That program then raises SIGBUS on Ubuntu 18.04 aarch64, Linux kernel 4.15.0 in a ThunderX2 server machine.

Unfortunately, I can't reproduce it on QEMU v4.0.0 user mode, I'm not sure why.

The fault appears to be optional and controlled by the SCTLR_ELx.SA and SCTLR_EL1.SA0 fields, I have summarized the related docs a bit further here.

Remove last characters from a string in C#. An elegant way?

You can use TrimEnd. It's efficient as well and looks clean.


java.sql.SQLException: Incorrect string value: '\xF0\x9F\x91\xBD\xF0\x9F...'

I had kind of the same problem and after going carefully against all charsets and finding that they were all right, I realized that the bugged property I had in my class was annotated as @Column instead of @JoinColumn (javax.presistence; hibernate) and it was breaking everything up.

How can I ask the Selenium-WebDriver to wait for few seconds in Java?

This thread is a bit older, but thought I'd post what I currently do (work in progress).

Though I'm still hitting situations where the system is under heavy load and when I click a submit button (e.g., login.jsp), all three conditions (see below) return true but the next page (e.g., home.jsp) hasn't started loading yet.

This is a generic wait method that takes a list of ExpectedConditions.

public boolean waitForPageLoad(int waitTimeInSec, ExpectedCondition<Boolean>... conditions) {
    boolean isLoaded = false;
    Wait<WebDriver> wait = new FluentWait<>(driver)
            .withTimeout(waitTimeInSec, TimeUnit.SECONDS)
            .pollingEvery(2, TimeUnit.SECONDS);
    for (ExpectedCondition<Boolean> condition : conditions) {
        isLoaded = wait.until(condition);
        if (isLoaded == false) {
            //Stop checking on first condition returning false.
    return isLoaded;

I have defined various reusable ExpectedConditions (three are below). In this example, the three expected conditions include document.readyState = 'complete', no "wait_dialog" present, and no 'spinners' (elements indicating async data is being requested).

Only the first one can be generically applied to all web pages.

 * Returns 'true' if the value of the 'window.document.readyState' via
 * JavaScript is 'complete'
public static final ExpectedCondition<Boolean> EXPECT_DOC_READY_STATE = new ExpectedCondition<Boolean>() {
    public Boolean apply(WebDriver driver) {
        String script = "if (typeof window != 'undefined' && window.document) { return window.document.readyState; } else { return 'notready'; }";
        Boolean result;
        try {
            result = ((JavascriptExecutor) driver).executeScript(script).equals("complete");
        } catch (Exception ex) {
            result = Boolean.FALSE;
        return result;
 * Returns 'true' if there is no 'wait_dialog' element present on the page.
public static final ExpectedCondition<Boolean> EXPECT_NOT_WAITING = new ExpectedCondition<Boolean>() {
    public Boolean apply(WebDriver driver) {
        Boolean loaded = true;
        try {
            WebElement wait = driver.findElement("F"));
            if (wait.isDisplayed()) {
                loaded = false;
        } catch (StaleElementReferenceException serex) {
            loaded = false;
        } catch (NoSuchElementException nseex) {
            loaded = true;
        } catch (Exception ex) {
            loaded = false;
            System.out.println("EXPECTED_NOT_WAITING: UNEXPECTED EXCEPTION: " + ex.getMessage());
        return loaded;
 * Returns true if there are no elements with the 'spinner' class name.
public static final ExpectedCondition<Boolean> EXPECT_NO_SPINNERS = new ExpectedCondition<Boolean>() {
    public Boolean apply(WebDriver driver) {
        Boolean loaded = true;
        try {
        List<WebElement> spinners = driver.findElements(By.className("spinner"));
        for (WebElement spinner : spinners) {
            if (spinner.isDisplayed()) {
                loaded = false;
        }catch (Exception ex) {
            loaded = false;
        return loaded;

Depending on the page, I may use one or all of them:


There are also predefined ExpectedConditions in the following class:

Size-limited queue that holds last N elements in Java

The only thing I know that has limited space is the BlockingQueue interface (which is e.g. implemented by the ArrayBlockingQueue class) - but they do not remove the first element if filled, but instead block the put operation until space is free (removed by other thread).

To my knowledge your trivial implementation is the easiest way to get such an behaviour.

How to remove all duplicate items from a list

No, it's simply a typo, the "list" at the end must be capitalized. You can nest loops over the same variable just fine (although there's rarely a good reason to).

However, there are other problems with the code. For starters, you're iterating through lists, so i and j will be items not indices. Furthermore, you can't change a collection while iterating over it (well, you "can" in that it runs, but madness lies that way - for instance, you'll propably skip over items). And then there's the complexity problem, your code is O(n^2). Either convert the list into a set and back into a list (simple, but shuffles the remaining list items) or do something like this:

seen = set()
new_x = []
for x in xs:
    if x in seen:

Both solutions require the items to be hashable. If that's not possible, you'll probably have to stick with your current approach sans the mentioned problems.

add a string prefix to each value in a string column using Pandas

df['col'] = 'str' + df['col'].astype(str)


>>> df = pd.DataFrame({'col':['a',0]})
>>> df
0   a
1   0
>>> df['col'] = 'str' + df['col'].astype(str)
>>> df
0  stra
1  str0

What is the best algorithm for overriding GetHashCode?

Pretty much similar to nightcoder's solution except it's easier to raise primes if you want to.

PS: This is one of those times where you puke a little in your mouth, knowing that this could be refactored into one method with 9 default's but it would be slower, so you just close your eyes and try to forget about it.

/// <summary>
/// Try not to look at the source code. It works. Just rely on it.
/// </summary>
public static class HashHelper
    private const int PrimeOne = 17;
    private const int PrimeTwo = 23;

    public static int GetHashCode<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10>(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6, T7 arg7, T8 arg8, T9 arg9, T10 arg10)
            int hash = PrimeOne;
            hash = hash * PrimeTwo + arg1.GetHashCode();
            hash = hash * PrimeTwo + arg2.GetHashCode();
            hash = hash * PrimeTwo + arg3.GetHashCode();
            hash = hash * PrimeTwo + arg4.GetHashCode();
            hash = hash * PrimeTwo + arg5.GetHashCode();
            hash = hash * PrimeTwo + arg6.GetHashCode();
            hash = hash * PrimeTwo + arg7.GetHashCode();
            hash = hash * PrimeTwo + arg8.GetHashCode();
            hash = hash * PrimeTwo + arg9.GetHashCode();
            hash = hash * PrimeTwo + arg10.GetHashCode();

            return hash;

    public static int GetHashCode<T1, T2, T3, T4, T5, T6, T7, T8, T9>(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6, T7 arg7, T8 arg8, T9 arg9)
            int hash = PrimeOne;
            hash = hash * PrimeTwo + arg1.GetHashCode();
            hash = hash * PrimeTwo + arg2.GetHashCode();
            hash = hash * PrimeTwo + arg3.GetHashCode();
            hash = hash * PrimeTwo + arg4.GetHashCode();
            hash = hash * PrimeTwo + arg5.GetHashCode();
            hash = hash * PrimeTwo + arg6.GetHashCode();
            hash = hash * PrimeTwo + arg7.GetHashCode();
            hash = hash * PrimeTwo + arg8.GetHashCode();
            hash = hash * PrimeTwo + arg9.GetHashCode();

            return hash;

    public static int GetHashCode<T1, T2, T3, T4, T5, T6, T7, T8>(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6, T7 arg7, T8 arg8)
            int hash = PrimeOne;
            hash = hash * PrimeTwo + arg1.GetHashCode();
            hash = hash * PrimeTwo + arg2.GetHashCode();
            hash = hash * PrimeTwo + arg3.GetHashCode();
            hash = hash * PrimeTwo + arg4.GetHashCode();
            hash = hash * PrimeTwo + arg5.GetHashCode();
            hash = hash * PrimeTwo + arg6.GetHashCode();
            hash = hash * PrimeTwo + arg7.GetHashCode();
            hash = hash * PrimeTwo + arg8.GetHashCode();

            return hash;

    public static int GetHashCode<T1, T2, T3, T4, T5, T6, T7>(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6, T7 arg7)
            int hash = PrimeOne;
            hash = hash * PrimeTwo + arg1.GetHashCode();
            hash = hash * PrimeTwo + arg2.GetHashCode();
            hash = hash * PrimeTwo + arg3.GetHashCode();
            hash = hash * PrimeTwo + arg4.GetHashCode();
            hash = hash * PrimeTwo + arg5.GetHashCode();
            hash = hash * PrimeTwo + arg6.GetHashCode();
            hash = hash * PrimeTwo + arg7.GetHashCode();

            return hash;

    public static int GetHashCode<T1, T2, T3, T4, T5, T6>(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6)
            int hash = PrimeOne;
            hash = hash * PrimeTwo + arg1.GetHashCode();
            hash = hash * PrimeTwo + arg2.GetHashCode();
            hash = hash * PrimeTwo + arg3.GetHashCode();
            hash = hash * PrimeTwo + arg4.GetHashCode();
            hash = hash * PrimeTwo + arg5.GetHashCode();
            hash = hash * PrimeTwo + arg6.GetHashCode();

            return hash;

    public static int GetHashCode<T1, T2, T3, T4, T5>(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5)
            int hash = PrimeOne;
            hash = hash * PrimeTwo + arg1.GetHashCode();
            hash = hash * PrimeTwo + arg2.GetHashCode();
            hash = hash * PrimeTwo + arg3.GetHashCode();
            hash = hash * PrimeTwo + arg4.GetHashCode();
            hash = hash * PrimeTwo + arg5.GetHashCode();

            return hash;

    public static int GetHashCode<T1, T2, T3, T4>(T1 arg1, T2 arg2, T3 arg3, T4 arg4)
            int hash = PrimeOne;
            hash = hash * PrimeTwo + arg1.GetHashCode();
            hash = hash * PrimeTwo + arg2.GetHashCode();
            hash = hash * PrimeTwo + arg3.GetHashCode();
            hash = hash * PrimeTwo + arg4.GetHashCode();

            return hash;

    public static int GetHashCode<T1, T2, T3>(T1 arg1, T2 arg2, T3 arg3)
            int hash = PrimeOne;
            hash = hash * PrimeTwo + arg1.GetHashCode();
            hash = hash * PrimeTwo + arg2.GetHashCode();
            hash = hash * PrimeTwo + arg3.GetHashCode();

            return hash;

    public static int GetHashCode<T1, T2>(T1 arg1, T2 arg2)
            int hash = PrimeOne;
            hash = hash * PrimeTwo + arg1.GetHashCode();
            hash = hash * PrimeTwo + arg2.GetHashCode();

            return hash;

Excel formula to remove space between words in a cell

Suppose the data is in the B column, write in the C column the formula:

=SUBSTITUTE(B1," ","")

Copy&Paste the formula in the whole C column.

edit: using commas or semicolons as parameters separator depends on your regional settings (I have to use the semicolons). This is weird I think. Thanks to @tocallaghan and @pablete for pointing this out.

Javascript counting number of objects in object

Try Demo Here

var list ={}; var count= Object.keys(list).length;

How to get thread id of a pthread in linux c program?

pthread_self() function will give the thread id of current thread.

pthread_t pthread_self(void);

The pthread_self() function returns the Pthread handle of the calling thread. The pthread_self() function does NOT return the integral thread of the calling thread. You must use pthread_getthreadid_np() to return an integral identifier for the thread.


pthread_id_np_t   tid;
tid = pthread_getthreadid_np();

is significantly faster than these calls, but provides the same behavior.

pthread_id_np_t   tid;
pthread_t         self;
self = pthread_self();
pthread_getunique_np(&self, &tid);

Difference between window.location.href and top.location.href

window.location.href returns the location of the current page.

top.location.href (which is an alias of returns the location of the topmost window in the window hierarchy. If a window has no parent, top is a reference to itself (in other words, window ===

top is useful both when you're dealing with frames and when dealing with windows which have been opened by other pages. For example, if you have a page called test.html with the following script:


The resulting alert will have the full path to test.html – not about:blank, which is what window.location.href would return.

To answer your question about redirecting, go with window.location.assign(url);

Where are the Android icon drawables within the SDK?

You can find android drawables icons from the example path below...


Error during SSL Handshake with remote server

I have 2 servers setup on docker, reverse proxy & web server. This error started happening for all my websites all of a sudden after 1 year. When setting up earlier, I generated a self signed certificate on the web server.

So, I had to generate the SSL certificate again and it started working...

openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout ssl.key -out ssl.crt

"Use of undeclared type" in Swift, even though type is internal, and exists in same module

When testing Swift code that belongs to the application, first make sure the test target is building the application as a dependency. Then, in your test, import the application as a module. For example:

@testable import MyApplication

This will make the Swift objects that are part of the application available to the test.

Why is my method undefined for the type object?

Try this.

public static void main(String[] args) {
    EchoServer0 myServer;
    myServer = new EchoServer0();

What you were trying to do was declaring a variable of type Object, not creating anything for that variable to reference, then trying to call a method that didn't exist (in the class Object) on an object that hadn't been created. It was never going to work.

PHP order array by date?

He was considering having the date as a key, but worried that values will be written one above other, all I wanted to show (maybe not that obvious, that why I do edit) is that he can still have values intact, not written one above other, isn't this okay?!

 'title_id_32'=>'Good morning', 
 'title_id_21'=>'Blue sky',
 'date'=>'1 May 2002'

 'title_id_20'=>'Old times',
  'date'=>'2 May   2002 '

 echo '<pre>';

Python pandas insert list into a cell

Also getting

ValueError: Must have equal len keys and value when setting with an iterable,

using .at rather than .loc did not make any difference in my case, but enforcing the datatype of the dataframe column did the trick:

df['B'] = df['B'].astype(object)

Then I could set lists, numpy array and all sorts of things as single cell values in my dataframes.

“tag already exists in the remote" error after recreating the git tag

Some good answers here. Especially the one by @torek. I thought I'd add this work-around with a little explanation for those in a rush.

To summarize, what happens is that when you move a tag locally, it changes the tag from a non-Null commit value to a different value. However, because git (as a default behavior) doesn't allow changing non-Null remote tags, you can't push the change.

The work-around is to delete the tag (and tick remove all remotes). Then create the same tag and push.

Getting full JS autocompletion under Sublime Text

Suggestions are (basically) based on the text in the current open file and any snippets or completions you have defined (ref). If you want more text suggestions, I'd recommend:

As a side note, I'd really recommend installing Package control to take full advantage of the Sublime community. Some of the options above use Package control. I'd also highly recommend the tutsplus Sublime tutorial videos, which include all sorts of information about improving your efficiency when using Sublime.

How to parse a date?

We now have a more modern way to do this work.


The java.time framework is bundled with Java 8 and later. See Tutorial. These new classes are inspired by Joda-Time, defined by JSR 310, and extended by the ThreeTen-Extra project. They are a vast improvement over the troublesome old classes, java.util.Date/.Calendar et al.

Note that the 3-4 letter codes like EDT are neither standardized nor unique. Avoid them whenever possible. Learn to use ISO 8601 standard formats instead. The java.time framework may take a stab at translating, but many of the commonly used codes have duplicate values.

By the way, note how java.time by default generates strings using the ISO 8601 formats but extended by appending the name of the time zone in brackets.

String input = "Thu Jun 18 20:56:02 EDT 2009";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern ( "EEE MMM d HH:mm:ss zzz yyyy" , Locale.ENGLISH );
ZonedDateTime zdt = formatter.parse ( input , ZonedDateTime :: from );

Dump to console.

System.out.println ( "zdt : " + zdt );

When run.

zdt : 2009-06-18T20:56:02-04:00[America/New_York]

Adjust Time Zone

For fun let's adjust to the India time zone.

ZonedDateTime zdtKolkata = zdt.withZoneSameInstant ( ZoneId.of ( "Asia/Kolkata" ) );

zdtKolkata : 2009-06-19T06:26:02+05:30[Asia/Kolkata]

Convert to j.u.Date

If you really need a java.util.Date object for use with classes not yet updated to the java.time types, convert. Note that you are losing the assigned time zone, but have the same moment automatically adjusted to UTC.

java.util.Date date = java.util.Date.from( zdt.toInstant() );

How to iterate over a string in C?

sizeof(source) returns the number of bytes required by the pointer char*. You should replace it with strlen(source) which will be the length of the string you're trying to display.

Also, you should probably replace printf("%s",source[i]) with printf("%c",source[i]) since you're displaying a character.

Could not connect to SMTP host: localhost, port: 25; nested exception is: Connection refused: connect

The mail server on CentOS 6 and other IPv6 capable server platforms may be bound to IPv6 localhost (::1) instead of IPv4 localhost (

Typical symptoms:

[root@host /]# telnet 25
telnet: connect to address Connection refused

[root@host /]# telnet localhost 25
Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 host ESMTP Exim 4.72 Wed, 14 Aug 2013 17:02:52 +0100

[root@host /]# netstat -plant | grep 25
tcp        0      0 :::25                       :::*                        LISTEN      1082/exim           

If this happens, make sure that you don't have two entries for localhost in /etc/hosts with different IP addresses, like this (bad) example:

[root@host /]# cat /etc/hosts localhost.localdomain localhost localhost4.localdomain4 localhost4
::1       localhost localhost.localdomain localhost6 localhost6.localdomain6

To avoid confusion, make sure you only have one entry for localhost, preferably an IPv4 address, like this:

[root@host /]# cat /etc/hosts localhost  localhost.localdomain   localhost4.localdomain4 localhost4
::1       localhost6 localhost6.localdomain6

How to get the first five character of a String

Kindly try this code when str is less than 5.

string strModified = str.Substring(0,str.Length>5?5:str.Length);

How do I call a Django function on button click?

There are 2 possible solutions that I personally use

1.without using form

 <button type="submit" value={{excel_path}} onclick="location.href='{% url 'downloadexcel' %}'" name='mybtn2'>Download Excel file</button>

2.Using Form

<form action="{% url 'downloadexcel' %}" method="post">
{% csrf_token %}

 <button type="submit" name='mybtn2' value={{excel_path}}>Download results in Excel</button>

Where should have this


Get name of current script in Python

we can try this to get current script name without extension.

import os

script_name = os.path.splitext(os.path.basename(__file__))[0]

What are the valid Style Format Strings for a Reporting Services [SSRS] Expression?

As mentioned, you can use:

=Format(Fields!Price.Value, "C")

A digit after the "C" will specify precision:

=Format(Fields!Price.Value, "C0")
=Format(Fields!Price.Value, "C1")

You can also use Excel-style masks like this:

=Format(Fields!Price.Value, "#,##0.00")

Haven't tested the last one, but there's the idea. Also works with dates:

=Format(Fields!Date.Value, "yyyy-MM-dd")

Uncompress tar.gz file

gunzip <filename>


tar -xvf <tar-file-name>

sql select with column name like

Here is a nice way to display the information that you want:

SELECT B.table_catalog as 'Database_Name',
         B.table_name as 'Table_Name',
        stuff((select ', ' + A.column_name
              where A.Table_name = B.Table_Name
              FOR XML PATH(''),TYPE).value('(./text())[1]','NVARCHAR(MAX)')
              , 1, 2, '') as 'Columns'
  WHERE B.TABLE_NAME like '%%'
        AND B.COLUMN_NAME like '%%'
  GROUP BY B.Table_Catalog, B.Table_Name
  Order by 1 asc

Add anything between either '%%' in the main select to narrow down what tables and/or column names you want.

What is the color code for transparency in CSS?

how to make transparent elements with css:

CSS for IE:

filter: alpha(opacity = 52);

CSS for other browsers:


Checking if a variable is an integer in PHP

All $_GET parameters have a string datatype, therefore, is_int will always return false.

You can see this by calling var_dump:

var_dump($_GET['p']); // string(2) "54"

Using is_numeric will provide the desired result (mind you, that allows values such as: 0x24).

Npm Error - No matching version found for

first, in C:\users\your PC write npm uninstall -g create-react-app then, create your project folder with npx create-react-app folder-name.

SQLRecoverableException: I/O Exception: Connection reset

Change the setup for your application, so you this parameter[] next to the java command:

java [your command]

Ref :-

PHP/MySQL insert row then get 'id'

Try like this you can get the answer:

// Check connection
if (mysqli_connect_errno())
  echo "Failed to connect to MySQL: " . mysqli_connect_error();

mysqli_query($con,"INSERT INTO new values('nameuser','2015-09-12')");

// Print auto-generated id
echo "New record has id: " . mysqli_insert_id($con);


Have a look at following links:

Also please have a note that this extension was deprecated in PHP 5.5 and removed in PHP 7.0

How to check if any flags of a flag combination are set?

How about

if ((letter & Letters.AB) > 0)


if statements matching multiple values

In or C# I would expect that the fastest general approach to compare a variable against any reasonable number of separately-named objects (as opposed to e.g. all the things in a collection) will be to simply compare each object against the comparand much as you have done. It is certainly possible to create an instance of a collection and see if it contains the object, and doing so may be more expressive than comparing the object against all items individually, but unless one uses a construct which the compiler can explicitly recognize, such code will almost certainly be much slower than simply doing the individual comparisons. I wouldn't worry about speed if the code will by its nature run at most a few hundred times per second, but I'd be wary of the code being repurposed to something that's run much more often than originally intended.

An alternative approach, if a variable is something like an enumeration type, is to choose power-of-two enumeration values to permit the use of bitmasks. If the enumeration type has 32 or fewer valid values (e.g. starting Harry=1, Ron=2, Hermione=4, Ginny=8, Neville=16) one could store them in an integer and check for multiple bits at once in a single operation ((if ((thisOne & (Harry | Ron | Neville | Beatrix)) != 0) /* Do something */. This will allow for fast code, but is limited to enumerations with a small number of values.

A somewhat more powerful approach, but one which must be used with care, is to use some bits of the value to indicate attributes of something, while other bits identify the item. For example, bit 30 could indicate that a character is male, bit 29 could indicate friend-of-Harry, etc. while the lower bits distinguish between characters. This approach would allow for adding characters who may or may not be friend-of-Harry, without requiring the code that checks for friend-of-Harry to change. One caveat with doing this is that one must distinguish between enumeration constants that are used to SET an enumeration value, and those used to TEST it. For example, to set a variable to indicate Harry, one might want to set it to 0x60000001, but to see if a variable IS Harry, one should bit-test it with 0x00000001.

One more approach, which may be useful if the total number of possible values is moderate (e.g. 16-16,000 or so) is to have an array of flags associated with each value. One could then code something like "if (((characterAttributes[theCharacter] & chracterAttribute.Male) != 0)". This approach will work best when the number of characters is fairly small. If array is too large, cache misses may slow down the code to the point that testing against a small number of characters individually would be faster.

how to set imageview src?

Each image has a resource-number, which is an integer. Pass this number to "setImageResource" and you should be ok.

Check this link for further information:



Use sudo with password as parameter

The -S switch makes sudo read the password from STDIN. This means you can do

echo mypassword | sudo -S command

to pass the password to sudo

However, the suggestions by others that do not involve passing the password as part of a command such as checking if the user is root are probably much better ideas for security reasons

Set output of a command as a variable (with pipes)

Your way can't work for two reasons.

You need to use set /p text= for setting the variable with user input.
The other problem is the pipe.
A pipe starts two asynchronous cmd.exe instances and after finishing the job both instances are closed.

That's the cause why it seems that the variables are not set, but a small example shows that they are set but the result is lost later.

set myVar=origin
echo Hello | (set /p myVar= & set myVar)
set myVar



Alternatives: You can use the FOR loop to get values into variables or also temp files.

for /f "delims=" %%A in ('echo hello') do set "var=%%A"
echo %var%


>output.tmp echo Hello
>>output.tmp echo world

<output.tmp (
  set /p line1=
  set /p line2=
echo %line1%
echo %line2%

Alternative with a macro:

You can use a batch macro, this is a bit like the bash equivalent

@echo off

REM *** Get version string 
%$set% versionString="ver"
echo The version is %versionString[0]%

REM *** Get all drive letters
`%$set% driveLetters="wmic logicaldisk get name /value | findstr "Name""
call :ShowVariable driveLetters

The definition of the macro can be found at
SO:Assign output of a program to a variable using a MS batch file

Trusting all certificates using HttpClient over HTTPS

I used this and It works for me on all OS.

 * Disables the SSL certificate checking for new instances of {@link HttpsURLConnection} This has been created to
 * aid testing on a local box, not for use on production.

private static void disableSSLCertificateChecking() {
    TrustManager[] trustAllCerts = new TrustManager[] { new X509TrustManager() {
        public X509Certificate[] getAcceptedIssuers() {
            return null;

        public void checkClientTrusted(X509Certificate[] arg0, String arg1) throws CertificateException {
            // Not implemented

        public void checkServerTrusted(X509Certificate[] arg0, String arg1) throws CertificateException {
            // Not implemented
    } };

    try {
        SSLContext sc = SSLContext.getInstance("TLS");

        sc.init(null, trustAllCerts, new;

    } catch (KeyManagementException e) {
    } catch (NoSuchAlgorithmException e) {

PHP: Update multiple MySQL fields in single query

If you are using pdo, it will look like

$sql = "UPDATE users SET firstname = :firstname, lastname = :lastname WHERE id= :id";
$query = $this->pdo->prepare($sql);
$result = $query->execute(array(':firstname' => $firstname, ':lastname' => $lastname, ':id' => $id));

Console.WriteLine and generic List

List<int> list = new List<int> { 1, 3, 5 };
list.ForEach(x => Console.WriteLine(x));

Edit: Dammit! took too long to open visual studio to test it.

How do I get a file name from a full path with PHP?

There are several ways to get the file name and extension. You can use the following one which is easy to use.

$url = '';
$file = file_get_contents($url); // To get file
$name = basename($url); // To get file name
$ext = pathinfo($url, PATHINFO_EXTENSION); // To get extension
$name2 =pathinfo($url, PATHINFO_FILENAME); // File name without extension

Regular expression replace in C#

You can do it this with two replace's

//let stw be "John Smith $100,000.00 M"

sb_trim = Regex.Replace(stw, @"\s+\$|\s+(?=\w+$)", ",");
//sb_trim becomes "John Smith,100,000.00,M"

sb_trim = Regex.Replace(sb_trim, @"(?<=\d),(?=\d)|[.]0+(?=,)", "");
//sb_trim becomes "John Smith,100000,M"


how can I Update top 100 records in sql server

What's even cooler is the fact that you can use an inline Table-Valued Function to select which (and how many via TOP) row(s) to update. That is:

SET Column1=@Value1
FROM tvfSelectLatestRowOfMyTableMatchingCriteria(@Param1,@Param2,@Param3)

For the table valued function you have something interesting to select the row to update like:

CREATE FUNCTION tvfSelectLatestRowOfMyTableMatchingCriteria
    @Param1 INT,
    @Param2 INT,
    @Param3 INT
    SELECT TOP(1) MyTable.*
    FROM MyTable
    JOIN MyOtherTable
      ON ...
    JOIN WhoKnowsWhatElse
      ON ...
    WHERE MyTable.SomeColumn=@Param1 AND ...
    ORDER BY MyTable.SomeDate DESC

..., and there lies (in my humble opinion) the true power of updating only top selected rows deterministically while at the same time simplifying the syntax of the UPDATE statement.

How to get the previous URL in JavaScript?

If you want to go to the previous page without knowing the url, you could use the new History api.

history.back(); //Go to the previous page
history.forward(); //Go to the next page in the stack
history.go(index); //Where index could be 1, -1, 56, etc.

But you can't manipulate the content of the history stack on browser that doesn't support the HTML5 History API

For more information see the doc

JavaScript Regular Expression Email Validation

this is the one i am using on my page.


Java function for arrays like PHP's join()?

java.util.Arrays has an 'asList' method. Together with the java.util.List/ArrayList API this gives you all you need:;

private static String[] join(String[] array1, String[] array2) {

    List<String> list = new ArrayList<String>(Arrays.asList(array1));
    return list.toArray(new String[0]);

How to Extract Year from DATE in POSTGRESQL

This line solved my same problem in postgresql:

SELECT DATE_PART('year', column_name::date) from tableName;

If you want month, then simply replacing year with month solves that as well and likewise.

Multiple scenarios @RequestMapping produces JSON/XML together with Accept or ResponseEntity

All your problems are that you are mixing content type negotiation with parameter passing. They are things at different levels. More specific, for your question 2, you constructed the response header with the media type your want to return. The actual content negotiation is based on the accept media type in your request header, not response header. At the point the execution reaches the implementation of the method getPersonFormat, I am not sure whether the content negotiation has been done or not. Depends on the implementation. If not and you want to make the thing work, you can overwrite the request header accept type with what you want to return.

return new ResponseEntity<>(PersonFactory.createPerson(), httpHeaders, HttpStatus.OK);

Reason to Pass a Pointer by Reference in C++?

I have had to use code like this to provide functions to allocate memory to a pointer passed in and return its size because my company "object" to me using the STL

 int iSizeOfArray(int* &piArray) {
    piArray = new int[iNumberOfElements];
    return iNumberOfElements;

It is not nice, but the pointer must be passed by reference (or use double pointer). If not, memory is allocated to a local copy of the pointer if it is passed by value which results in a memory leak.

OAuth 2.0 Authorization Header

You can still use the Authorization header with OAuth 2.0. There is a Bearer type specified in the Authorization header for use with OAuth bearer tokens (meaning the client app simply has to present ("bear") the token). The value of the header is the access token the client received from the Authorization Server.

It's documented in this spec:


   GET /resource HTTP/1.1
   Authorization: Bearer mF_9.B5f-4.1JqM

Where mF_9.B5f-4.1JqM is your OAuth access token.

Trim to remove white space

Why not try this?


  a b c



Rename Excel Sheet with VBA Macro

Suggest you add handling to test if any of the sheets to be renamed already exist:

Sub Test()

Dim ws As Worksheet
Dim ws1 As Worksheet
Dim strErr As String

On Error Resume Next
For Each ws In ActiveWorkbook.Sheets
Set ws1 = Sheets(ws.Name & "_v1")
    If ws1 Is Nothing Then
        ws.Name = ws.Name & "_v1"
         strErr = strErr & ws.Name & "_v1" & vbNewLine
    End If
Set ws1 = Nothing
On Error GoTo 0

If Len(strErr) > 0 Then MsgBox strErr, vbOKOnly, "these sheets already existed"

End Sub

Ways to insert javascript into URL?

old question that I stumbled into that I believe deserves an update... You can infact execute javascript from the URL, and you can get creative about it too. I recently made a members only area that I wanted to remind someone what their password was, so I was looking for a non-local alert...of course you can embed an alert into the page itself, but then its public. the difference here is I can create a link and slip some JS into the href so clicking on the link will generate the alert.

here is what I mean >>

<a href="javascript:alert('the secret is to ask.');window.location.replace('');">You can have anything</a>

and so upon clicking the link, the user is given an alert with the info, then they are taken to the new page.

obviously you could also write an onClick, but the href works just fine when you slip it through the URL, just remember to prepend it with "javascript:"

*works in chrome, didnt check anything else.

How can I find WPF controls by name or type?

Since the question is general enough that it might attract people looking for answers to very trivial cases: if you just want a child rather than a descendant, you can use Linq:

private void ItemsControlItem_Loaded(object sender, RoutedEventArgs e)
    if (SomeCondition())
        var children = (sender as Panel).Children;
        var child = (from Control child in children
                 where child.Name == "NameTextBox"
                 select child).First();

or of course the obvious for loop iterating over Children.

android ellipsize multiline textview

I have had the same Problem. I fixed it by just deleting android:ellipsize="marquee"