public boolean onKeyDown(int key, KeyEvent event) {
  switch (key) { 
  case KeyEvent.KEYCODE_SEARCH:
   break;
  case KeyEvent.KEYCODE_BACK:
   Intent intent = new Intent();
    setResult(RESULT_OK, intent);
    finish();
   break;
  case KeyEvent.KEYCODE_DPAD_CENTER:
   break;
  default:
   return false;
  }
  return false;
 }
另一頁如果有回傳值
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
  super.onActivityResult(requestCode, resultCode, data);
  switch (resultCode) {  
  case RESULT_OK:
   // 回上一頁囉
   break;
  default:
   break;
  }
 }