自由手記

PowerManager pm = (PowerManager)Context.getSystemServier(Context.POWER_SERVICE);

 
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK, "My Tag");
wl.acquire();
// ..screen will stay on during this section..
wl.release();

 
PARTIAL_WAKE_LOCK : CPU(On*), Screen(OFF), Keyboard(OFF)
SCREEN_DIM_WAKE_LOCK : CPU(On), Screen(Dim), Keyboard(OFF)
SCREEN_BRIGHT_WAKE_LOCK : CPU(On), Screen(Bright), Keyboard(OFF)
FULL_WAKE_LOCK : CPU(On), Screen(Bright), Keyboard(Bright)

PowerManagerService.mNotificationTask 
  -> WindowManagerPolicy.screenTurnedOn() 
      -> KeyguardViewMediator.onScreenTurnedOn(); 
  -> WindowManagerPolicy.screenTurnedOff() 
      -> KeyguardViewMediator.onScreenTurnedOff();