title: How to detect Back Key in my CustomView
body: <p>I want to detect Back Key event in my CustomView (e.g., EditText). In many case, it has been achieved by overriding the <code>onKeyDown()</code> or <code>dispatchKeyEvent()</code>, under the condition that my CustomView obtains focus.</p>
  
  <p><strong>CustomView.java</strong></p>
  
  <pre><code>@Override
  public boolean onKeyDown(int keyCode, KeyEvent event) {
      if( keyCode == KeyEvent.KEYCODE_BACK) {
          ..... 
          return true;
      }else{
          return super.onKeyDown(keyCode, event);
      }
  }
  </code></pre>
  
  <p>However, if an Activity including the CustomView is also overriding the <code>onKeyDown()</code> or <code>dispatchKeyEvent()</code>, it couldn't work much. That is, the Activity has obtained the Back-KeyEvent before the CustomView has.</p>
  
  <p>I preferentially want to catch the Back-KeyEvent before Activity does.</p>
  
  <p>please tell me some ideas about this problem.
  Thank you.</p>