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POUsing AsyncTask to load Images in ListView
 

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    <p>I have one ListView which can hold an image. It depends if image exists or not in SDCARD.</p> <p>Here my example code:</p> <pre><code>public class MainActivity extends Activity { ListView mListView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mListView = new ListView(this); setContentView(mListView); String[] arr = new String[] { "/example/images/1.jpg", "/example/images/2.jpg", "/example/images/3.jpg", "/example/images/4.jpg", "/example/images/5.jpg", "/example/images/6.jpg", "/example/images/7.jpg", "/example/images/8.jpg", "/example/images/9.jpg", "/example/images/1.jpg", "/example/images/2.jpg", "/example/images/3.jpg", "/example/images/4.jpg", "/example/images/5.jpg", "/example/images/6.jpg", "/example/images/7.jpg", "/example/images/8.jpg", "/example/images/9.jpg", "/example/images/1.jpg", "/example/images/2.jpg", "/example/images/3.jpg", "/example/images/4.jpg", "/example/images/5.jpg", "/example/images/6.jpg", "/example/images/7.jpg", "/example/images/8.jpg", "/example/images/9.jpg", "/example/images/1.jpg", "/example/images/2.jpg", "/example/images/3.jpg", "/example/images/4.jpg", "/example/images/5.jpg", "/example/images/6.jpg", "/example/images/7.jpg", "/example/images/8.jpg", "/example/images/9.jpg"}; List&lt;String&gt; list = Arrays.asList(arr); MyAdapter adapter = new MyAdapter(this, R.layout.listitem_imv, list); mListView.setAdapter(adapter); } class MyAdapter extends ArrayAdapter&lt;String&gt;{ List&lt;String&gt; mList; LayoutInflater mInflater; int mResource; public MyAdapter(Context context, int resource, List&lt;String&gt; objects) { super(context, resource, objects); mResource = resource; mInflater = getLayoutInflater(); mList = objects; } @Override public View getView(int position, View convertView, ViewGroup parent) { View view; if(convertView == null){ view = mInflater.inflate(mResource, null); }else{ view = convertView; } ImageView imageView = (ImageView) view.findViewById(R.id.imv); TextView textView = (TextView) view.findViewById(R.id.txv); imageView.setTag(mList.get(position));//tag of imageView == path to image new LoadImage().execute(imageView); textView.setText(mList.get(position).toString()); return view; } } class LoadImage extends AsyncTask&lt;Object, Void, Bitmap&gt;{ private ImageView imv; private String path; @Override protected Bitmap doInBackground(Object... params) { imv = (ImageView) params[0]; path = imv.getTag().toString(); Bitmap bitmap = null; File file = new File( Environment.getExternalStorageDirectory().getAbsolutePath() + path); if(file.exists()){ bitmap = BitmapFactory.decodeFile(file.getAbsolutePath()); } return bitmap; } @Override protected void onPostExecute(Bitmap result) { if(result != null &amp;&amp; imv != null){ imv.setVisibility(View.VISIBLE); imv.setImageBitmap(result); }else{ imv.setVisibility(View.GONE); } } } } </code></pre> <p>The 'sdcard/example/images' directory has the images: 1.jpg, 2.jpg, 3.jpg, 4.jpg, 6.jpg, 7.jpg and 9.jpg. the expected result is: <img src="https://i.stack.imgur.com/5yFKI.png" alt="example"></p> <p>But, if I scroll the list quickly, some images are inserted in the wrong items. It happens due to use of convertView in getView() method.</p> <p>If I use the following code, the code works fine:</p> <pre><code> //if(convertView == null){ // view = mInflater.inflate(mResource, null); //}else{ // view = convertView; //} view = mInflater.inflate(mResource, null); </code></pre> <p>When list scrolled quickly, two asyncTasks can reference one same View, due to use of convertView. How Can I cancel AsyncTask when the View is no longer visible?(and is useb by another item of ListView)</p> <p><strong>edit</strong></p> <pre><code> @Override protected void onPostExecute(Bitmap result) { if(result != null &amp;&amp; imv != null){ if(imv.getTag().equals(path)){ imv.setVisibility(View.VISIBLE); imv.setImageBitmap(result); }else{ imv.setVisibility(View.GONE); } }else{ imv.setVisibility(View.GONE); } } </code></pre>
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