java - android ArrayAdapter で textView が見つからないのはなぜですか?

Question

私は次のコードを書きました：

TodosOverviewActivity extends ListActivity{

    @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.todo_list);
            this.getListView().setDividerHeight(2);
            registerForContextMenu(getListView());
            fillData();
        }



    private void fillData() {

    fetchEvents();

     adapter2 = new MySimpleArrayAdapter
                (this, nameOfEvent, startDates, descriptions);
     setListAdapter(adapter2);
            }

public class MySimpleArrayAdapter extends ArrayAdapter<String> {

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        LayoutInflater inflater = (LayoutInflater) mContext
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View rowView = inflater.inflate(R.layout.todo_list, parent, false);

        TextView titleTextView = (TextView) rowView
                .findViewById(R.id.todo_row_title);
        TextView dateTextView = (TextView) rowView
                .findViewById(R.id.todo_row_date);
        ImageView imageView = (ImageView) rowView
                .findViewById(R.id.todo_row_image);

            titleTextView.setText(mTitles[position]);

    ..

    }

ただし、 nullpointer では失敗しますtitleTextView。私は何が欠けていますか？