Android SDKのAdapterView.SetOnItemClickListenerから ActivityのViewパーツをさわる

OnItemClickListener.partof.java

@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
        long id) {
    Button button1 = (Button) parent.getRootView().findViewById(R.id.button1);
    button1.setTextColor(android.graphics.Color.RED);
}