WeirdNerd WeirdNerd - 6 months ago 29
Android Question

Duplicates in listview - Android

I am getting duplicate values in listviews but I am sure that there are no duplicates in the list that I am using.

Here is the below code,

public class MainActivity extends Activity {

ArrayList<String> listOfSongs = new ArrayList<String>();
ListView liststructure;
final private int REQUEST_CODE_ASK_PERMISSIONS = 123;
String MUSIC_STRING = MediaStore.Audio.Media.IS_MUSIC + "!=0";
String[] STAR = {"*"};
Uri uri=null;
String orderColumns = MediaStore.Audio.AudioColumns.TITLE + " COLLATE LOCALISED ASC";
private final int REQUEST_GRANTED_BY_USER = 1;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

liststructure = (ListView) findViewById(R.id.listView);
SongsList list = new SongsList(MainActivity.this, listOfSongs);
liststructure.setAdapter(list);

checkPermissions();
Toast.makeText(getApplicationContext(), "Total number of Items are:" + liststructure.getAdapter().getCount() , Toast.LENGTH_LONG).show();

}

private void checkPermissions() {

if (Build.VERSION.SDK_INT >= 23) {
int permissionCheck = ContextCompat.checkSelfPermission(MainActivity.this,
Manifest.permission.READ_EXTERNAL_STORAGE);
if (permissionCheck != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, REQUEST_GRANTED_BY_USER);
}else{
getInfoFromDevice();
}
}else{
getInfoFromDevice();
}
}
void getInfoFromDevice() {
uri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
Cursor cursor = getContentResolver().query(uri, STAR, MUSIC_STRING, null, null);

if (cursor != null)

{
if (cursor.moveToFirst()) {
do {
String name = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DISPLAY_NAME));
String data = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DATA));
String album = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM));
String albumID = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM_ID));
listOfSongs.add(name);
} while (cursor.moveToNext());
}

Log.d("COUNT","COUNT is " + listOfSongs.size());
}
listOfSongs.size();
}
}


SongList.java

public class SongsList extends BaseAdapter {

ArrayList<String> songs;
Context c;

SongsList(Context c, ArrayList<String> songs)
{
this.c=c;
this.songs = songs;
}


@Override
public int getCount() {
return songs.size();
}

@Override
public Object getItem(int i) {
return songs.get(i);
}

@Override
public long getItemId(int i) {
return i;
}

@Override
public View getView(int i, View view, ViewGroup viewGroup) {

TextView tv;
ViewHolder vh;
LayoutInflater inflater = (LayoutInflater)
c.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);

if(view ==null)
{
view = inflater.inflate(R.layout.green,viewGroup,false);
vh = new ViewHolder(view);
view.setTag(vh);
vh.tv.setText(songs.get(i));
}
else{
vh = (ViewHolder) view.getTag();
}
return view;
}
}


I also tried the below questions,

Duplicated entries in ListView

Result: I have already implemented this.

Android ListView Duplicates entries

Result: This did not work.

All elements of An ArrayList change when a new one is added?

Result: No looping and object creation code.

ListView Duplicates Android

Result: Already implemented this.

Could any one tell me why is the listview displaying the duplicates ?

Answer

I think the solution is actually in the first answer you linked to.

Try changing your code to something like:

if(view ==null)
    {
       view = inflater.inflate(R.layout.green,viewGroup,false);
        vh = new ViewHolder(view);
        view.setTag(vh);
        vh.tv.setText(songs.get(i));
    }
    else{
        vh = (ViewHolder) view.getTag();
        vh.tv.setText(songs.get(i));
    }

In the else statement, you're reusing a view that's already been created, however you still need to update the data in that view.

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