如何在sensorManager.registerListener()中调用onResume()？

Question

我正在用一个应用程序进行测试，该应用程序可以对加速度计数据进行采样并进行处理。

第一次安装应用程序时，onSensorChanged()以1/2的速度调用，其速率在samplePeriodUs中指定

我尝试在onPause()中注销并注册onPause侦听器。一种看起来可行的方法是在onResume()中输入1/2的样本率。这不是正确的做事方式吗？

 public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    sensorManager = (SensorManager) getActivity().getSystemService(Context.SENSOR_SERVICE);
    accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    sensorManager.registerListener(this, accelerometer, 20000); }

 public void onResume() {
    super.onResume();
    sensorManager.unregisterListener(this);
    sensorManager.registerListener(this, accelerometer, 10000);
}

public void onPause() {
    super.onPause();
    sensorManager.unregisterListener(this); }

我期望sensorManager.registerListener(这个，加速度计，20000)；用于onResume()和onCreate()

Answer 1

这种行为确实很奇怪。下面是我在机器学习应用程序中管理传感器的方法。

private SensorManager mSensorManager;
private Sensor mAccelerometer, mGyroscope, mMagnetometer;

@Override
protected void onResume() {
    super.onResume();
    mSensorManager.registerListener(mSensorEventListener, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);
    mSensorManager.registerListener(mSensorEventListener, mGyroscope, SensorManager.SENSOR_DELAY_NORMAL);
    mSensorManager.registerListener(mSensorEventListener, mMagnetometer, SensorManager.SENSOR_DELAY_NORMAL);
}

@Override
protected void onPause() {
    super.onPause();
    mSensorManager.unregisterListener(mSensorEventListener);
}

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);

    mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_LINEAR_ACCELERATION);
    mGyroscope = mSensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
    mMagnetometer = mSensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);

    mSensorManager.registerListener(mSensorEventListener, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);

}

/**
* Listener that handles sensor events
*/
private final SensorEventListener mSensorEventListener = new SensorEventListener() {
    @Override
    public void onSensorChanged(SensorEvent event) {
        //if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
        if (event.sensor.getType() == Sensor.TYPE_LINEAR_ACCELERATION) {
            // Do work
        } else if (event.sensor.getType() == Sensor.TYPE_GYROSCOPE) {
            // Do work
        } else if (event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD) {
            // Do work
        }
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int i) {
    }
}; 

完整的项目源可以在https://github.com/Wickapps/Activity-Tracker找到。