Question

I saw that there were many problems regarding notifyDataSetChanged(). I’ve looked through many of them and none of the solutions worked for me.

I am using ArrayList to set my list, and after my ArrayList is updated, i ran notifyDataSetChanged(). The new list is added onto the previous one.

lets say first list is a,b and new list is a,b,c. what i get in the end is a,b,a,b,c.
and each time updating this happens again with the new list.

I’ve tried other such as invalidate(), adapter clear(), refreshDrawableState() etc and nothing worked.

Thank you in advance.

Here is the simplified code, a note that changing MainActivity extends Activity to ListActivity crashes the program even after i change the code in .xml file.

public class MainActivity extends Activity 
{
ArrayList<String> names = new ArrayList<String>();
ArrayAdapter arrayAdapter = null;

@Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    ListView lv1 = (ListView) findViewById(R.id.listview);
    arrayAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, names);
    lv1.setAdapter(arrayAdapter);

}

//code here to edit the ArrayList names.

public void onResume() 
{
    super.onResume();  // Always call the superclass method first

    //the activity need to be updated everytime it resumes.
    arrayAdapter.notifyDataSetChanged();

}
}

Answer 1

Seems like you are not properly updating the array list. Please try logging the array list contents after updating.