JB2上如何实现按power键亮屏的时候，能把触摸板上的home/menu/back虚拟按键的背光点亮？

在android 4.2上的版本，google defautl就已经把触摸板上虚拟按键的背光功能去掉了，如想实现按power键亮屏的时候，能把home/menu/back这些键的背光灯点亮，请参考下面的实现方法：
KeyguardViewMediator.java

1,

 public KeyguardViewMediator(Context context, LockPatternUtils lockPatternUtils) {

         mContext = context;

         mPM=(PowerManager) context.getSystemService(Context.POWER_SERVICE);

         mUserManager = (UserManager) mContext.getSystemService(Context.USER_SERVICE);

 //add code here ===============

         mButtonWakelock=mPM.newWakeLock(PowerManager.FULL_WAKE_LOCK|PowerManager.ACQUIRE_CAUSES_WAKEUP,"button backlight");

 //add code here ===============

  

 2,

  private void handleWakeWhenReady(int keyCode, int wakeMSGId) {

         if (DBG_WAKE) KeyguardUtils.xlogD(TAG, ">>>handleWakeWhenReady(" + keyCode + ") Before--synchronized (KeyguardViewMediator.this) wakeMSGId = " + wakeMSGId); /// M:

         synchronized (KeyguardViewMediator.this) {

             if (DBG_WAKE) KeyguardUtils.xlogD(TAG, "handleWakeWhenReady(" + keyCode + ") wakeMSGId = " + wakeMSGId);

  

             // this should result in a call to 'poke wakelock' which will set a timeout

             // on releasing the wakelock

             if (!mKeyguardViewManager.wakeWhenReadyTq(keyCode)) {

                // poke wakelock ourselves if keyguard is no longer active

                 KeyguardUtils.xlogD(TAG, "mKeyguardViewManager.wakeWhenReadyTq did not poke wake lock, so poke it ourselves");

                 userActivity();

             }

  

             /**

              * Now that the keyguard is ready and has poked the wake lock, we can

              * release the handoff wakelock

              */

             mWakeAndHandOff.release();

 //add code here =============

                      mButtonWakelock.acquire(3000);

 //add code here =============

             if (DBG_WAKE) KeyguardUtils.xlogD(TAG, "<<<handleWakeWhenReady(" + keyCode + ") wakeMSGId = " + wakeMSGId);

         }

     }

 3，

 keyguardviewmediator.java

  

     private void handleKeyguardDone(boolean wakeup) {

         KeyguardUtils.xlogD(TAG, "handleKeyguardDone, wakeup=" + wakeup);

 //add code here ================

               if (mButtonWakelock.isHeld())

                      mButtonWakelock.release();

 //add code here ================

         handleHide();

         if (wakeup) {

             wakeUp();

         }

  

         sendUserPresentBroadcast();

     }

 4，

 phonewindowmanager.java

  

  /** {@inheritDoc} */

     @Override

     public int interceptKeyBeforeQueueing(KeyEvent event, int policyFlags, boolean isScreenOn) {

  

 int result;

         if ((isScreenOn && !mHeadless) || (isInjected && !isWakeKey)) {

             // When the screen is on or if the key is injected pass the key to the application.

             result = ACTION_PASS_TO_USER;

         } else {

             // When the screen is off and the key is not injected, determine whether

             // to wake the device but don't pass the key to the application.

             result = 0;

             if (down && isWakeKey && isWakeKeyWhenScreenOff(keyCode)) {

                 if (keyguardActive) {

                     // If the keyguard is showing, let it wake the device when ready.

                     mKeyguardMediator.onWakeKeyWhenKeyguardShowingTq(keyCode);

                 } else {

                     // Otherwise, wake the device ourselves.

                     result |= ACTION_WAKE_UP;

 //add code her =================================

                                    mKeyguardMediator.pokeWakelock();

 //add code her =================================

                 }

             }

         }

 5，

 KeyguardViewMediator.java

  

 //add by mtk

        public void pokeWakelock()

        {             mButtonWakelock.acquire(3000);

        }

  //add by mtk