title: How to get power button keycode without screen lock
body: <p>I 'm trying to display <code>keycode</code> when user press specific key in my program. I can get all of keys keycode, i.e. vol_up / vol_down / Camera etc. But the screen will be locked/off when I press Power button, and I can't see the keycode of power key in the screen. Could someone tell me how to get the keycode of Power button and the screen won't be off/locked when pressing it?</p>
  
  <p>Thanks a lot.
  Qin</p>