[android] notifyDataSetChanged example

I'm trying to use in my Android Application the notifyDataSetChanged() method for an ArrayAdapter but it doesn't work for me.

I found as answer here, that notifyDataSetChanged() should run in the main thread, but there was no example for that.

Could anybody send an example or at least a link?!

I know this is a late response but I was facing a similar issue and I managed to solve it by using notifyDataSetChanged() in the right place.

So my situation was as follows.

I had to update a listview in an action bar tab (fragment) with contents returned from a completely different activity. Initially however, the listview would not reflect any changes. However, when I clicked another tab and then returned to the desired tab,the listview would be updated with the correct content from the other activity. So to solve this I used notifyDataSetChanged() of the action bar adapter in the code of the activity which had to return the data.

This is the code snippet which I used in the activity.

@Override
public boolean onOptionsItemSelected(MenuItem item) {

    switch (item.getItemId()) 
    {
        case R.id.action_new_forward:

            FragmentTab2.mListAdapter.notifyDataSetChanged();//this updates the adapter in my action bar tab
            Intent ina = new Intent(getApplicationContext(), MainActivity.class);
            ina.putExtra("stra", values1);
            startActivity(ina);// This is the code to start the parent activity of my action bar tab(fragment).
    }
}

This activity would return some data to FragmentTab2 and it would directly update my listview in FragmentTab2.

Hope someone finds this useful!

You can use the runOnUiThread() method as follows. If you're not using a ListActivity, just adapt the code to get a reference to your ArrayAdapter.

final ArrayAdapter adapter = ((ArrayAdapter)getListAdapter());
runOnUiThread(new Runnable() {
    public void run() {
        adapter.notifyDataSetChanged();
    }
});

I recently wrote on this topic, though this post it old, I thought it will be helpful to someone who wants to know how to implement BaseAdapter.notifyDataSetChanged() step by step and in a correct way.

Please follow How to correctly implement BaseAdapter.notifyDataSetChanged() in Android or the newer blog BaseAdapter.notifyDataSetChanged().

I had the same problem and I prefer not to replace the entire ArrayAdapter with a new instance continuously. Thus I have the AdapterHelper do the heavy lifting somewhere else.

Add this where you would normally (try to) call notify

new AdapterHelper().update((ArrayAdapter)adapter, new ArrayList<Object>(yourArrayList));
adapter.notifyDataSetChanged();

AdapterHelper class

public class AdapterHelper {
    @SuppressWarnings({ "rawtypes", "unchecked" })
    public void update(ArrayAdapter arrayAdapter, ArrayList<Object> listOfObject){
        arrayAdapter.clear();
        for (Object object : listOfObject){
            arrayAdapter.add(object);
        }
    }
}