private void lock() {
        PowerManager mPowerManager = (PowerManager) getSystemService(POWER_SERVICE);
        wakeLock = mPowerManager.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK |
                PowerManager.ON_AFTER_RELEASE, "tag");
        wakeLock.acquire();
    }

    private void unLock() {
        if (null != wakeLock) {
            wakeLock.release();
        }
    }