A simpler approach is to capture the Back button press and call moveTaskToBack(true) as follows:
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
moveTaskToBack(true);
return true;
}
return super.onKeyDown(keyCode, event);
}
Android 2.0 introduced a new onBackPressed method, and these recommendations on how to handle the Back button