how to determine device orientation from the senso

问题:

My activity is locked on LANDSCAPE. But still I need to know the orientation of the device. So I have elected to use sensors. I have the following code

sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION), SensorManager.SENSOR_DELAY_NORMAL);
...
@Override
  public void onSensorChanged(SensorEvent event) {
    float[] values = event.values;

    // Movement
    float azimuth = values[0];
    float pitch = values[1];
    float roll = values[2];

    if ((-110 <= pitch && pitch <= -70) || (70 <= pitch && pitch <= 110)) {
      //PORTRAIT MODE
      portraitPitch = true;
      landscapePitch = false;
      Log.d(TAG, "portrait mode: pitch = " + pitch);
    } else if ((-20 <= pitch && pitch <= 20) || (-200 <= pitch && pitch <= -160) || (160 <= pitch && pitch <= 200)) {
      //LANDSCAPE MODE
      portraitPitch = false;
      landscapePitch = true;
      Log.d(TAG, "landscape mode : pitch = " + pitch);
    }

    if ((-20 <= roll && roll <= 20)) {
      //PORTRAIT MODE
      portraitRoll = true;
      landscapePitch = false;
      Log.d(TAG, "portrait mode: roll = " + roll);
    } else if ((-110 <= roll && roll <= -70) || (70 <= roll && roll <= 110)) {
      //LANDSCAPE MODE
      portraitRoll = false;
      landscapePitch = true;
      Log.d(TAG, "landscape mode : roll = " + roll);
    }

    if (portraitPitch && portraitRoll && !portrait) {
      portrait = true;
      landscape = false;
      rotateIconsToPortraitMode();
      Log.d(TAG, "portrait mode for icons: pitch = " + pitch + ", roll = " + roll);
    }

    if (landscapePitch && landscapeRoll && !landscape) {
      landscape = true;
      portrait = false;
      rotateIconsToLandscapeMode();
      Log.d(TAG, "landscape mode for icons: pitch = " + pitch + ", roll = " + roll);
    }
}

My code is not working reliably, in fact, the otateIconsToLandscapeMode() is never reached.

How do I use the information about azimuth, pitch, and roll to determine the PORTRAIT or LANDSCAPE orientation of the device?` I hope my question is specific enough to warrant a specific answer. Thanks.

回答1:

In oncreate instantiate an OrientationEventListener

OrientationEventListener orientationEventListener = new OrientationEventListener(this)
    {
        @Override
        public void onOrientationChanged(int orientation)
        {
            Log.d(TAG, "orientation = " + orientation);
        }
    }; 

    orientationEventListener.enable();

Using the orientation value you can determine whether the device in in Portrait or Landscape.

回答2:

If LANDSCAPE vs PORTRAIT orientation is all you need, then the pitch value should be sufficient. It may not be perfect depending on your specific needs. But from my understanding, you can simply use pitch. So you it exactly as you have it, just ignore roll.