不能正确释放PowerManager.WakeLock

Question

我用PowerManager.WakeLock表示Sensor.TYPE_LIGHT in Activity。它工作得很好，但是当我关闭/转到其他Activity SensorEventListener时，如果get传感器发生变化，请继续打开/关闭屏幕。

代码样本

    SensorManager mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    Sensor mLightSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
    PowerManager mPowerManager = (PowerManager) getSystemService(Context.POWER_SERVICE);
    PowerManager.WakeLock mWakeLock = mPowerManager.newWakeLock(PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK, "tag");

SensorEventListener接口法

@Override
public void onSensorChanged(SensorEvent event) {
    float[] lux = event.values;

    if (lux[0] <= 200) {
        mWakeLock.acquire();
    } else {
        if (mWakeLock.isHeld()) {
            mWakeLock.release();
        }
    }
}

SensorManager侦听器

 @Override
protected void onResume() {
    super.onResume();
    mSensorManager.registerListener(this, mLightSensor, SensorManager.SENSOR_DELAY_FASTEST);

}

@Override
protected void onPause() {
    super.onPause();
    mSensorManager.unregisterListener(this, mLightSensor);

}

@Override
protected void onDestroy() {
    super.onDestroy();
    if (mWakeLock.isHeld()) {
        mWakeLock.release();
    }

}

那么如何正确地释放和禁用WakeLock。提前谢谢。

Answer 1

我的错是使用SensorEventListener。可能是双重的WakeLock.acquire()，每次都这么叫。关键是在onCreate()中获取，在onDestroy()中发布。

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
PowerManager mPowerManager = (PowerManager) getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock mWakeLock = mPowerManager.newWakeLock(PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK, "tag");
mWakeLock.acquire();
}

@Override
protected void onDestroy() {
    if (mWakeLock.isHeld()) {
        mWakeLock.release();
    }
    super.onDestroy();
}