用Sensor.TYPE_MAGNETIC_FIELD发现的方位比Sensor.TYPE_ORIENTATION更不稳定

Question

我正在做一些增强现实应用，我需要方位角来计算一些物体在屏幕上的位置。我试图使用Sensor.TYPE_ORIENTATION获取定位数据，由于不推荐使用它，所以我尝试了Sensor.TYPE_MAGNETIC_FIELD。我的问题是，与Sensor.TYPE_MAGNETIC_FIELD和SensorManager.getOrientation相比，用Sensor.TYPE_ORIENTATION获得的值是相当不稳定的，这使得我的对象在屏幕上跳了一点点(当不将值在一个范围内移动时，比如方位角-5 azimuth+5，而它几乎不与Sensor.TYPE_ORIENTATION一起移动)。

Sensor.TYPE_ORIENTATION

public void onSensorChanged(SensorEvent event)
{
    if(event.sensor.getType() == Sensor.TYPE_ORIENTATION)
    {
        newAzimuth = (event.values[0] + 360)%360;            
        azimuth = (float) ((newAzimuth * kFilteringFactor) + (azimuth * (1.0 - kFilteringFactor)));       
    }
}

Sensor.TYPE_MAGNETIC_FIELD

public void onSensorChanged(SensorEvent event) {
    switch (event.sensor.getType()) {
        case Sensor.TYPE_MAGNETIC_FIELD:
            mags = event.values.clone();
            break;
        case Sensor.TYPE_ACCELEROMETER:
            accels = event.values.clone();
            break;
    }
    if (mags != null && accels != null) {
        SensorManager.getRotationMatrix(R, I, accels, mags);
        SensorManager.remapCoordinateSystem(R, SensorManager.AXIS_X,
                SensorManager.AXIS_Z, remappedR);
        SensorManager.getOrientation(remappedR, orientation);
        newAzimuth = (float) Math.round(Math.toDegrees(orientation[0]));
        newAzimuth = (newAzimuth + 360)%360;
        azimuth = (float) (newAzimuth * kFilteringFactor) + (azimuth * (1.0f - kFilteringFactor));
    }
}

Answer 1

只有在使用SensorManager.DELAY_FASTER时才会发生这种情况。使用SensorManager.SENSOR_DELAY_GAME，值更稳定.