[android] How to handle back button in activity

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