How do I display a list of images using the ListView? I am downloading the images at run time. The total number of images is not fixed.
This question is related to
android
listview
android-image
Here is the simple ListView with different images. First of all you have to copy the different kinds of images and paste it to the res/drawable-hdpi in your project. Images should be (.png)file format. then copy this code.
In main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/textview"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<ListView
android:id="@+id/listview"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
create listview_layout.xml and paste this code
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<ImageView
android:id="@+id/flag"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:contentDescription="@string/hello"
android:paddingTop="10dp"
android:paddingRight="10dp"
android:paddingBottom="10dp" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/txt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="15dp"
android:text="TextView1" />
<TextView
android:id="@+id/cur"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="10dp"
android:text="TextView2" />
</LinearLayout>
In your Activity
package com.test;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ListView;
import android.widget.SimpleAdapter;
public class SimpleListImageActivity extends Activity {
// Array of strings storing country names
String[] countries = new String[] {
"India",
"Pakistan",
"Sri Lanka",
"China",
"Bangladesh",
"Nepal",
"Afghanistan",
"North Korea",
"South Korea",
"Japan"
};
// Array of integers points to images stored in /res/drawable-hdpi/
//here you have to give image name which you already pasted it in /res/drawable-hdpi/
int[] flags = new int[]{
R.drawable.image1,
R.drawable.image2,
R.drawable.image3,
R.drawable.image4,
R.drawable.image5,
R.drawable.image6,
R.drawable.image7,
R.drawable.image8,
R.drawable.image9,
R.drawable.image10,
};
// Array of strings to store currencies
String[] currency = new String[]{
"Indian Rupee",
"Pakistani Rupee",
"Sri Lankan Rupee",
"Renminbi",
"Bangladeshi Taka",
"Nepalese Rupee",
"Afghani",
"North Korean Won",
"South Korean Won",
"Japanese Yen"
};
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Each row in the list stores country name, currency and flag
List<HashMap<String,String>> aList = new ArrayList<HashMap<String,String>>();
for(int i=0;i<10;i++){
HashMap<String, String> hm = new HashMap<String,String>();
hm.put("txt", "Country : " + countries[i]);
hm.put("cur","Currency : " + currency[i]);
hm.put("flag", Integer.toString(flags[i]) );
aList.add(hm);
}
// Keys used in Hashmap
String[] from = { "flag","txt","cur" };
// Ids of views in listview_layout
int[] to = { R.id.flag,R.id.txt,R.id.cur};
// Instantiating an adapter to store each items
// R.layout.listview_layout defines the layout of each item
SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), aList, R.layout.listview_layout, from, to);
// Getting a reference to listview of main.xml layout file
ListView listView = ( ListView ) findViewById(R.id.listview);
// Setting the adapter to the listView
listView.setAdapter(adapter);
}
}
This is the full code.you can make changes to your need... Comments are welcome
Six years on, this is still at the top for some searches. Things have changed a lot since then. Now the defacto standard is more or less to use Volley and the NetworkImageView which takes care of the heavy lifting for you.
Assuming that you already have your Apaters, Loaders and ListFragments setup properly, this official google tutorial explains how to use NetworkImageView to load the images. Images are automatically loaded in a background thread and the view updated on the UI thread. It even supports caching.
To get the data from the database, you'd use a SimpleCursorAdapter.
I think you can directly bind the SimpleCursorAdapter to a ListView - if not, you can create a custom adapter class that extends SimpleCursorAdapter with a custom ViewBinder that overrides setViewValue.
Look at the Notepad tutorial to see how to use a SimpleCursorAdapter.
File name should match the layout id which in this example is : items_list_item.xml in the layout folder of your application
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
>
<ImageView android:id="@+id/R.id.list_item_image"
android:layout_width="100dip"
android:layout_height="wrap_content" />
</LinearLayout>
package studRecords.one;
import java.util.List;
import java.util.Vector;
import android.app.Activity;
import android.app.ListActivity;
import android.content.Context;
import android.content.Intent;
import android.net.ParseException;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
public class studRecords extends ListActivity
{
static String listName = "";
static String listUsn = "";
static Integer images;
private LayoutInflater layoutx;
private Vector<RowData> listValue;
RowData rd;
static final String[] names = new String[]
{
"Name (Stud1)", "Name (Stud2)",
"Name (Stud3)","Name (Stud4)"
};
static final String[] usn = new String[]
{
"1PI08CS016","1PI08CS007","1PI08CS017","1PI08CS047"
};
private Integer[] imgid =
{
R.drawable.stud1,R.drawable.stud2,R.drawable.stud3,
R.drawable.stud4
};
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.mainlist);
layoutx = (LayoutInflater) getSystemService(
Activity.LAYOUT_INFLATER_SERVICE);
listValue = new Vector<RowData>();
for(int i=0;i<names.length;i++)
{
try
{
rd = new RowData(names[i],usn[i],i);
}
catch (ParseException e)
{
e.printStackTrace();
}
listValue.add(rd);
}
CustomAdapter adapter = new CustomAdapter(this, R.layout.list,
R.id.detail, listValue);
setListAdapter(adapter);
getListView().setTextFilterEnabled(true);
}
public void onListItemClick(ListView parent, View v, int position,long id)
{
listName = names[position];
listUsn = usn[position];
images = imgid[position];
Intent myIntent = new Intent();
Intent setClassName = myIntent.setClassName("studRecords.one","studRecords.one.nextList");
startActivity(myIntent);
}
private class RowData
{
protected String mNames;
protected String mUsn;
protected int mId;
RowData(String title,String detail,int id){
mId=id;
mNames = title;
mUsn = detail;
}
@Override
public String toString()
{
return mNames+" "+mUsn+" "+mId;
}
}
private class CustomAdapter extends ArrayAdapter<RowData>
{
public CustomAdapter(Context context, int resource,
int textViewResourceId, List<RowData> objects)
{
super(context, resource, textViewResourceId, objects);
}
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
ViewHolder holder = null;
TextView title = null;
TextView detail = null;
ImageView i11=null;
RowData rowData= getItem(position);
if(null == convertView)
{
convertView = layoutx.inflate(R.layout.list, null);
holder = new ViewHolder(convertView);
convertView.setTag(holder);
}
holder = (ViewHolder) convertView.getTag();
i11=holder.getImage();
i11.setImageResource(imgid[rowData.mId]);
title = holder.gettitle();
title.setText(rowData.mNames);
detail = holder.getdetail();
detail.setText(rowData.mUsn);
return convertView;
}
private class ViewHolder
{
private View mRow;
private TextView title = null;
private TextView detail = null;
private ImageView i11=null;
public ViewHolder(View row)
{
mRow = row;
}
public TextView gettitle()
{
if(null == title)
{
title = (TextView) mRow.findViewById(R.id.title);
}
return title;
}
public TextView getdetail()
{
if(null == detail)
{
detail = (TextView) mRow.findViewById(R.id.detail);
}
return detail;
}
public ImageView getImage()
{
if(null == i11)
{
i11 = (ImageView) mRow.findViewById(R.id.img);
}
return i11;
}
}
}
}
//mainlist.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
I came up with a solution that I call “BatchImageDownloader” that has served well. Here’s a quick summary of how it is used:
Keep a global HashMap (ideally in your Application object) that serves as a cache of drawable objects
In the getView() method of your List Adapter, use the drawable from the cache for populating the ImageView in your list item.
Create an instance of BatchImageDownloader, passing in your ListView Adapter
Call addUrl() for each image that needs to be fetched/displayed
When done, call execute(). This fires an AsyncTask that fetches all images, and as each image is fetched and added to the cache, it refreshes your ListView (by calling notifyDataSetChanged())
The approach has the following advantages:
Here is the source code of BatchImageDownloader:
package com.mobrite.androidutils;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.graphics.drawable.Drawable;
import android.os.AsyncTask;
import android.widget.BaseAdapter;
public class BatchImageDownloader extends AsyncTask<Void, Void, Void> {
List<String> imgUrls = new ArrayList<String>();
BaseAdapter adapter;
HashMap<String, Drawable> imageCache;
public BatchImageDownloader(BaseAdapter adapter,
HashMap<String, Drawable> imageCache) {
this.adapter = adapter;
this.imageCache = imageCache;
}
public void addUrl(String url) {
imgUrls.add(url);
}
@Override
protected Void doInBackground(Void... params) {
for (String url : imgUrls) {
if (!imageCache.containsKey(url)) {
Drawable bm = downloadImage(url);
if (null != bm) {
imageCache.put(url, bm);
publishProgress();
}
}
}
return null;
}
@Override
protected void onProgressUpdate(Void... values) {
adapter.notifyDataSetChanged();
}
@Override
protected void onPostExecute(Void result) {
adapter.notifyDataSetChanged();
}
public Drawable downloadImage(String url) {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet request = new HttpGet(url);
try {
HttpResponse response = httpClient.execute(request);
InputStream stream = response.getEntity().getContent();
Drawable drawable = Drawable.createFromStream(stream, "src");
return drawable;
} catch (ClientProtocolException e) {
e.printStackTrace();
return null;
} catch (IllegalStateException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
}
I'd start with something like this (and if there is something wrong with my code, I'd of course appreciate any comment):
public class ItemsList extends ListActivity {
private ItemsAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.items_list);
this.adapter = new ItemsAdapter(this, R.layout.items_list_item, ItemManager.getLoadedItems());
setListAdapter(this.adapter);
}
private class ItemsAdapter extends ArrayAdapter<Item> {
private Item[] items;
public ItemsAdapter(Context context, int textViewResourceId, Item[] items) {
super(context, textViewResourceId, items);
this.items = items;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.items_list_item, null);
}
Item it = items[position];
if (it != null) {
ImageView iv = (ImageView) v.findViewById(R.id.list_item_image);
if (iv != null) {
iv.setImageDrawable(it.getImage());
}
}
return v;
}
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
this.adapter.getItem(position).click(this.getApplicationContext());
}
}
E.g. extending ArrayAdapter with own type of Items (holding information about your pictures) and overriden getView() method, that prepares view for items within list. There is also method add() on ArrayAdapter to add items to the end of the list.
R.layout.items_list is simple layout with ListView
R.layout.items_list_item is layout representing one item in list
We need to implement two layouts. One to hold listview and another to hold row item of listview. Implement your own custom adapter. Idea is to include one textview and one imageview.
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View single_row = inflater.inflate(R.layout.list_row, null,
true);
TextView textView = (TextView) single_row.findViewById(R.id.textView);
ImageView imageView = (ImageView) single_row.findViewById(R.id.imageView);
textView.setText(color_names[position]);
imageView.setImageResource(image_id[position]);
return single_row;
}
Next we implement functionality in main activity to include images and text data dynamically during runtime. You can pass dynamically created text array and image id array to the constructor of custom adapter.
Customlistadapter adapter = new Customlistadapter(this, image_id, text_name);
I came up with a solution that I call “BatchImageDownloader” that has served well. Here’s a quick summary of how it is used:
Keep a global HashMap (ideally in your Application object) that serves as a cache of drawable objects
In the getView() method of your List Adapter, use the drawable from the cache for populating the ImageView in your list item.
Create an instance of BatchImageDownloader, passing in your ListView Adapter
Call addUrl() for each image that needs to be fetched/displayed
When done, call execute(). This fires an AsyncTask that fetches all images, and as each image is fetched and added to the cache, it refreshes your ListView (by calling notifyDataSetChanged())
The approach has the following advantages:
Here is the source code of BatchImageDownloader:
package com.mobrite.androidutils;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.graphics.drawable.Drawable;
import android.os.AsyncTask;
import android.widget.BaseAdapter;
public class BatchImageDownloader extends AsyncTask<Void, Void, Void> {
List<String> imgUrls = new ArrayList<String>();
BaseAdapter adapter;
HashMap<String, Drawable> imageCache;
public BatchImageDownloader(BaseAdapter adapter,
HashMap<String, Drawable> imageCache) {
this.adapter = adapter;
this.imageCache = imageCache;
}
public void addUrl(String url) {
imgUrls.add(url);
}
@Override
protected Void doInBackground(Void... params) {
for (String url : imgUrls) {
if (!imageCache.containsKey(url)) {
Drawable bm = downloadImage(url);
if (null != bm) {
imageCache.put(url, bm);
publishProgress();
}
}
}
return null;
}
@Override
protected void onProgressUpdate(Void... values) {
adapter.notifyDataSetChanged();
}
@Override
protected void onPostExecute(Void result) {
adapter.notifyDataSetChanged();
}
public Drawable downloadImage(String url) {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet request = new HttpGet(url);
try {
HttpResponse response = httpClient.execute(request);
InputStream stream = response.getEntity().getContent();
Drawable drawable = Drawable.createFromStream(stream, "src");
return drawable;
} catch (ClientProtocolException e) {
e.printStackTrace();
return null;
} catch (IllegalStateException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
}
I'd start with something like this (and if there is something wrong with my code, I'd of course appreciate any comment):
public class ItemsList extends ListActivity {
private ItemsAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.items_list);
this.adapter = new ItemsAdapter(this, R.layout.items_list_item, ItemManager.getLoadedItems());
setListAdapter(this.adapter);
}
private class ItemsAdapter extends ArrayAdapter<Item> {
private Item[] items;
public ItemsAdapter(Context context, int textViewResourceId, Item[] items) {
super(context, textViewResourceId, items);
this.items = items;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.items_list_item, null);
}
Item it = items[position];
if (it != null) {
ImageView iv = (ImageView) v.findViewById(R.id.list_item_image);
if (iv != null) {
iv.setImageDrawable(it.getImage());
}
}
return v;
}
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
this.adapter.getItem(position).click(this.getApplicationContext());
}
}
E.g. extending ArrayAdapter with own type of Items (holding information about your pictures) and overriden getView() method, that prepares view for items within list. There is also method add() on ArrayAdapter to add items to the end of the list.
R.layout.items_list is simple layout with ListView
R.layout.items_list_item is layout representing one item in list
File name should match the layout id which in this example is : items_list_item.xml in the layout folder of your application
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
>
<ImageView android:id="@+id/R.id.list_item_image"
android:layout_width="100dip"
android:layout_height="wrap_content" />
</LinearLayout>
I'd start with something like this (and if there is something wrong with my code, I'd of course appreciate any comment):
public class ItemsList extends ListActivity {
private ItemsAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.items_list);
this.adapter = new ItemsAdapter(this, R.layout.items_list_item, ItemManager.getLoadedItems());
setListAdapter(this.adapter);
}
private class ItemsAdapter extends ArrayAdapter<Item> {
private Item[] items;
public ItemsAdapter(Context context, int textViewResourceId, Item[] items) {
super(context, textViewResourceId, items);
this.items = items;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.items_list_item, null);
}
Item it = items[position];
if (it != null) {
ImageView iv = (ImageView) v.findViewById(R.id.list_item_image);
if (iv != null) {
iv.setImageDrawable(it.getImage());
}
}
return v;
}
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
this.adapter.getItem(position).click(this.getApplicationContext());
}
}
E.g. extending ArrayAdapter with own type of Items (holding information about your pictures) and overriden getView() method, that prepares view for items within list. There is also method add() on ArrayAdapter to add items to the end of the list.
R.layout.items_list is simple layout with ListView
R.layout.items_list_item is layout representing one item in list
We need to implement two layouts. One to hold listview and another to hold row item of listview. Implement your own custom adapter. Idea is to include one textview and one imageview.
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View single_row = inflater.inflate(R.layout.list_row, null,
true);
TextView textView = (TextView) single_row.findViewById(R.id.textView);
ImageView imageView = (ImageView) single_row.findViewById(R.id.imageView);
textView.setText(color_names[position]);
imageView.setImageResource(image_id[position]);
return single_row;
}
Next we implement functionality in main activity to include images and text data dynamically during runtime. You can pass dynamically created text array and image id array to the constructor of custom adapter.
Customlistadapter adapter = new Customlistadapter(this, image_id, text_name);
To get the data from the database, you'd use a SimpleCursorAdapter.
I think you can directly bind the SimpleCursorAdapter to a ListView - if not, you can create a custom adapter class that extends SimpleCursorAdapter with a custom ViewBinder that overrides setViewValue.
Look at the Notepad tutorial to see how to use a SimpleCursorAdapter.
Six years on, this is still at the top for some searches. Things have changed a lot since then. Now the defacto standard is more or less to use Volley and the NetworkImageView which takes care of the heavy lifting for you.
Assuming that you already have your Apaters, Loaders and ListFragments setup properly, this official google tutorial explains how to use NetworkImageView to load the images. Images are automatically loaded in a background thread and the view updated on the UI thread. It even supports caching.
Source: Stackoverflow.com