PowerManager管理亮灭屏操作

    /* 注册监听亮灭屏广播，当灭屏时，点亮屏幕 */
    BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Log.d(TAG, "action = " + intent.getAction());
            if (Intent.ACTION_SCREEN_ON.equalsIgnoreCase(intent.getAction())) {
                Log.d(TAG, "screen on.");
                mScreenOnTxt.setText("screen on");
            } else if (Intent.ACTION_SCREEN_OFF.equalsIgnoreCase(intent.getAction())) {
                Log.d(TAG, "screen off");
                mScreenOnTxt.setText("screen off");
                wakeUpScreen();
            }
        }
    };

    private void registerScreenOnReceiver() {
        IntentFilter filter = new IntentFilter();
        filter.addAction(Intent.ACTION_SCREEN_ON);
        filter.addAction(Intent.ACTION_SCREEN_OFF);
        registerReceiver(mBroadcastReceiver, filter);
    }

    private void wakeUpScreen() {
        PowerManager powerManager = (