Question

I have an Activity, which needs its orientation to be locked with

setRequestedOrientation(screenOrientation);

But I want to get orientation updates, so that I can do adjustments to the UI(imagine HTC camera app, when only button’s icons change orientation).
So I found this class. It delivers orientation values, between 0 and 360. Ho do I filter this values, i.e. perfect interval [a, b], and if a<x<b then orientation is landscape or portrait? Compute mean? Any hints?

Answer 1

It sounds like you are needing code to only react when the device’s orientation has changed to one of the 4 normal orientations instead of at every angle. This will filter the orientation to only values of 0, 90, 180 and 270 degrees:

OrientationEventListener myOrientationEventListener;
    int iOrientation;

    myOrientationEventListener = new OrientationEventListener(this, SensorManager.SENSOR_DELAY_NORMAL)
    {

        @Override
        public void onOrientationChanged(int iAngle)
        {                         // 0  15 30 45 60 75, 90 105, 120, 135, 150, 165, 180, 195, 210, 225, 240, 255, 270, 285, 300, 315, 330, 345
            final int iLookup[] = {0,   0, 0,90,90, 90,90, 90,  90, 180, 180, 180, 180, 180, 180, 270, 270, 270, 270, 270, 270, 0, 0, 0}; // 15-degree increments 
            if (iAngle != ORIENTATION_UNKNOWN)
            {
                int iNewOrientation = iLookup[iAngle / 15];
                if (iOrientation != iNewOrientation)
                {
                    iOrientation = iNewOrientation;
                    // take action on new orientation here
                }
            }
        }
    };

    // To display if orientation detection will work and enable it
    if (myOrientationEventListener.canDetectOrientation())
    {
    Toast.makeText(this, "Can DetectOrientation", Toast.LENGTH_LONG).show();
        myOrientationEventListener.enable();
    }
    else
    {
    Toast.makeText(this, "Can't DetectOrientation", Toast.LENGTH_LONG).show();
    }