title: Android backbutton override issue in 4.4.2
body: <p>I want to ask about back button override functionally.
  I am using this approach.</p>
  
  <pre><code>@Override
  public boolean onKeyDown(int keyCode, KeyEvent event)  {
  
      return super.onKeyDown(keyCode, event);
  }
  </code></pre>
  
  <p>It works fine all Android platforms but its not working fine on Anroird 4.4.2</p>
  
  <p>How can I implement backbutton override in Android 4.4.2? </p>