arcgis Listview

private ListView listView;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);
    listView = (ListView) findViewById(R.id.listview);
    final List<String> adapterData = new ArrayList<String>();
    for (int i = 0; i < 20; i++) {
        adapterData.add("ListItem" + i);
    }
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_gallery_item, adapterData);
    listView.setAdapter(adapter);
}