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Why is the LogCat showing NullPointerException when I use ArrayAdapter?

Ribbit App is showing NullPointer Exception when I use the array adapter. If i comment the statement setListAdapter(), the app is not crashing but this does not display the contents which I intent to display. Also, I created a similar fragment in another app, but there it does not crash. Please help me fix this out. The fragment code is

public class InboxFragment extends ListFragment {
protected ArrayList<ParseObject> myMessages = new ArrayList<ParseObject>();

public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_inbox, container,
    return rootView;

public void onResume() {
    ParseQuery<ParseObject> query = new ParseQuery<ParseObject>(
    query.whereEqualTo(ParseConstants.KEY_RECEPIENTSIDS, ParseUser

    query.findInBackground(new FindCallback<ParseObject>() {

        public void done(List<ParseObject> arg0, ParseException e) {
            if (e == null) {
                // success
                Toast.makeText(getListView().getContext(), "Loaded messages!",

                String usernames[] = new String[arg0.size()];
                for( int i=0; i<usernames.length; i++)
                    usernames[i] = arg0.get(i).getString(ParseConstants.KEY_SENDERNAME);
                ArrayAdapter<String> adapter = new ArrayAdapter<String>(getListView()
                        .getContext(), android.R.layout.simple_list_item_1, usernames

            } else {
                // failure
                Toast.makeText(getListView().getContext(), "Failed to load messages!",




Thanks in advance