Write a file in external storage in Android

Question

I want to create a file in external storage sdCard and write to it I have searched through internet and try but not getting the result I have added permission in Android Manifest file as well I am doing this on Emulator I am trying the following code and getting a ERRR    Could not create file    btnWriteSDFile    Button  findViewById R id btnWriteSDFile   btnWriteSDFile setOnClickListener new OnClickListener           private Throwable e        Override     public void onClick View v               write on SD card file data from the text box         try               File myFile   new File   sdcard mysdfile txt                myFile createNewFile                FileOutputStream fOut   new FileOutputStream myFile               OutputStreamWriter myOutWriter   new OutputStreamWriter fOut               myOutWriter append txtData getText                 myOutWriter close                fOut close               catch  Exception e                  Log e  ERRR    Could not create file  e                      onClick        btnWriteSDFile

User · Answer

Supplemental Answer

After writing to external storage, some file managers don't see the file right away. This can be confusing if a user thinks they copied something to the SD card, but then can't find it there. So after you copy the file, run the following code to notify file managers of its presence.

MediaScannerConnection.scanFile(
        context,
        new String[]{myFile.getAbsolutePath()},
        null,
        null);

See the documentation and this answer for more.

User · Answer

To write into external storage in Lollipop  devices we need    Add the following permission into Manifest           lt uses-permission android name  android permission WRITE EXTERNAL STORAGE    gt   Request an approval from the user          public static final int REQUEST WRITE STORAGE   112           private requestPermission Activity context               boolean hasPermission    ContextCompat checkSelfPermission context  Manifest permission WRITE EXTERNAL STORAGE     PackageManager PERMISSION GRANTED              if   hasPermission                  ActivityCompat requestPermissions context                   new String   Manifest permission WRITE EXTERNAL STORAGE                  REQUEST WRITE STORAGE                else                   You are allowed to write external storage               String path   Environment getExternalStorageDirectory   getAbsolutePath       new folder                File storageDir   new File path                if   storageDir exists    amp  amp   storageDir mkdirs                        This should never happen - log handled exception                               Handle the user response inside Activity    Override public void onRequestPermissionsResult int requestCode  String   permissions  int   grantResults         super onRequestPermissionsResult requestCode  permissions  grantResults         switch  requestCode               case Preferences REQUEST WRITE STORAGE             if  grantResults length  gt  0  amp  amp  grantResults 0      PackageManager PERMISSION GRANTED               Toast makeText this   The app was allowed to write to your storage    Toast LENGTH LONG  show                  Reload the activity with permission granted or use the features what required the permission            else              Toast makeText this   The app was not allowed to write to your storage  Hence  it cannot function properly  Please consider granting it this permission   Toast LENGTH LONG  show

User · Answer

The code below creates a Documents directory and then a sub-directory for the application and saved the files to it   public class loadDataTooDisk extends AsyncTask lt String  Integer  String gt        String sdCardFileTxt       Override     protected String doInBackground String    params                   check to see if external storage is avalibel         checkState            if canW    canR    true                          get the path to sdcard              File pathToExternalStorage   Environment getExternalStorageDirectory                  to this path add a new directory path and create new App dir  InstroList  in  documents Dir             File appDirectory   new File pathToExternalStorage getAbsolutePath        documents InstroList                   have the object build the directory structure  if needed              appDirectory mkdirs                  test to see if it is a Text file             if   myNewFileName endsWith   txt                                      Create a File for the output file data                 File saveFilePath   new File  appDirectory  myNewFileName                     Adds the textbox data to the file                 try                      String newline     r n                       FileOutputStream fos   new FileOutputStream  saveFilePath                       OutputStreamWriter OutDataWriter    new OutputStreamWriter fos                        OutDataWriter write equipNo getText     newline                          OutDataWriter append equipNo getText     newline                       OutDataWriter append equip Type getText     newline                       OutDataWriter append equip Make getText    newline                       OutDataWriter append equipModel No getText    newline                       OutDataWriter append equip Password getText    newline                       OutDataWriter append equipWeb Site getText    newline                         OutDataWriter append equipNotes getText                         OutDataWriter close                         fos flush                        fos close                      catch Exception e                       e printStackTrace                                                      return null            This one builds the file name     private String BuildNewFileName            creates a new filr name         Time today   new Time Time getCurrentTimezone             today setToNow             StringBuilder sb   new StringBuilder             sb append today year                          Year          sb append               sb append today monthDay                    Day of the month  1-31          sb append               sb append today month                        Month  0-11           sb append               sb append today format   k  M  S             Current time         sb append   txt                           Completed file name          myNewFileName   sb toString              Replace     with             myNewFileName   myNewFileName replaceAll                     return myNewFileName          Hope this helps  It took me a long time to get it working

User · Answer

You can find these method usefull in reading and writing data in android    public void saveData View view        String text    This is the text in the file  this is the part of the issue of the name and also called the name od the college        FileOutputStream fos   null      try           fos   openFileOutput  FILE NAME   MODE PRIVATE           fos write text getBytes             Toast makeText this   Data is saved    getFilesDir    Toast LENGTH SHORT  show          catch  FileNotFoundException e            e printStackTrace          catch  IOException e            e printStackTrace         finally           if  fos   null               try                   fos close                  catch  IOException e                    e printStackTrace                                       public void logData View view        FileInputStream fis   null       try           fis   openFileInput  FILE NAME            InputStreamReader isr   new InputStreamReader fis           BufferedReader br   new BufferedReader isr           StringBuilder sb   new StringBuilder            String text          while  text   br readLine       null               sb append text  append   n                Log e  TAG   text                                 catch  FileNotFoundException e            e printStackTrace          catch  IOException e            e printStackTrace         finally           if fis    null               try                   fis close                  catch  IOException e                    e printStackTrace

User · Answer

You can do this with this code also    public class WriteSDCard extends Activity     private static final String TAG    MEDIA    private TextView tv         Called when the activity is first created      Override  public void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout main            tv    TextView  findViewById R id TextView01       checkExternalMedia        writeToSDFile        readRaw            Method to check whether external media available and writable  This is adapted from    http   developer android com guide topics data data-storage html filesExternal      private void checkExternalMedia          boolean mExternalStorageAvailable   false      boolean mExternalStorageWriteable   false      String state   Environment getExternalStorageState         if  Environment MEDIA MOUNTED equals state                Can read and write the media         mExternalStorageAvailable   mExternalStorageWriteable   true        else if  Environment MEDIA MOUNTED READ ONLY equals state                Can only read the media         mExternalStorageAvailable   true          mExternalStorageWriteable   false        else              Can t read or write         mExternalStorageAvailable   mExternalStorageWriteable   false               tv append   n nExternal Media  readable                mExternalStorageAvailable   writable   mExternalStorageWriteable          Method to write ascii text characters to file on SD card  Note that you must add a     WRITE EXTERNAL STORAGE permission to the manifest file or this method will throw    a FileNotFound Exception because you won t have write permission      private void writeToSDFile            Find the root of the external storage         See http   developer android com guide topics data data-  storage html filesExternal      File root   android os Environment getExternalStorageDirectory         tv append   nExternal file system root    root           See http   stackoverflow com questions 3551821 android-write-to-sd-card-folder      File dir   new File  root getAbsolutePath       download        dir mkdirs        File file   new File dir   myData txt         try           FileOutputStream f   new FileOutputStream file           PrintWriter pw   new PrintWriter f           pw println  Hi   How are you            pw println  Hello            pw flush            pw close            f close          catch  FileNotFoundException e            e printStackTrace            Log i TAG           File not found  Did you                      add a WRITE EXTERNAL STORAGE permission to the   manifest           catch  IOException e            e printStackTrace                 tv append   n nFile written to   file          Method to read in a text file placed in the res raw directory of the application  The   method reads in all lines of the file sequentially      private void readRaw        tv append   nData read from res raw textfile txt         InputStream is   this getResources   openRawResource R raw textfile       InputStreamReader isr   new InputStreamReader is       BufferedReader br   new BufferedReader isr  8192         2nd arg is buffer size         More efficient  less readable  implementation of above is the composite expression       BufferedReader br   new BufferedReader new InputStreamReader              this getResources   openRawResource R raw textfile    8192          try           String test              while  true                              test   br readLine                      readLine   returns null if no more lines in the file             if test    null  break              tv append   n         test                     isr close            is close            br close          catch  IOException e            e printStackTrace              tv append   n nThat is all

User · Answer

Even though above answers are correct  I wanna add a notice to distinguish types of storage   Internal storage  It should say  private storage  because it belongs to the app and cannot be shared  Where it s saved is based on where the app installed  If the app was installed on an SD card  I mean the external storage card you put more into a cell phone for more space to store images  videos        your file will belong to the app means your file will be in an SD card  And if the app was installed on an Internal card  I mean the onboard storage card coming with your cell phone   your file will be in an Internal card  External storage   It should say  public storage  because it can be shared  And this mode divides into 2 groups  private external storage and public external storage  Basically  they are nearly the same  you can consult more from this site  https   developer android com training data-storage files A real SD card  I mean the external storage card you put more into a cell phone for more space to store images  videos        this was not stated clearly on Android docs  so many people might be confused with how to save files in this card   Here is the link to source code for cases I mentioned above  https   github com mttdat utils blob master utils src main java mttdat utils FileUtils java

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ContextWrapper contextWrapper   new ContextWrapper getApplicationContext       getappcontext for just this activity context get  File file   contextWrapper getDir file path  Context MODE PRIVATE      if   isExternalStorageAvailable      isExternalStorageReadOnly           saveToExternalStorage setEnabled false       else      External File   new File getExternalFilesDir file path   file name    if ready then create a file for external         try        FileInputStream fis   new FileInputStream External File      DataInputStream in   new DataInputStream fis      BufferedReader br  new BufferedReader new InputStreamReader in       String strLine     while   strLine   br readLine       null            myData   myData   strLine          in close          catch  IOException e          e printStackTrace          InputText setText  Save data of External file        myData     private static boolean isExternalStorageReadOnly        String extStorageState   Environment getExternalStorageState      if  Environment MEDIA MOUNTED READ ONLY equals extStorageState         return true        return false       private static boolean isExternalStorageAvailable       String extStorageState   Environment getExternalStorageState      if  Environment MEDIA MOUNTED equals extStorageState         return true        return false

User · Answer

You should read the documentation on storing stuff externally on Android  There s a multitude of problems that could exist with your current code  and I think going over the documentation might help you iron them out

[android] Write a file in external storage in Android

Supplemental Answer

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