Android detect screen orientation change when activity screen orientation is locked

I had to detect screen orientation changes, but my activity in the manifest file had to stay locked in android:screenOrientation="portrait" mode.

This way i was not able to use onConfigurationChanged . I had to monitor the sensor manager.

public class MainActivity extends Activity implements SensorEventListener {

	private SensorManager mSensorManager;
	private Sensor mRotationSensor;
	
	private static final int SENSOR_DELAY = 500 * 1000; // 500ms
	private static final int FROM_RADS_TO_DEGS = -57;
	private String oldtilt;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		try {
			mSensorManager = (SensorManager) getSystemService(Activity.SENSOR_SERVICE);
			mRotationSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR);
			mSensorManager.registerListener(this, mRotationSensor, SENSOR_DELAY);
		} catch (Exception e) {
			Toast.makeText(this, "Hardware compatibility issue", Toast.LENGTH_LONG).show();
		}
	}

	@Override
	public void onAccuracyChanged(Sensor sensor, int accuracy) {
		// TODO Auto-generated method stub
	}

	@Override
	public void onSensorChanged(SensorEvent event) {
		if (event.sensor == mRotationSensor) {
	    	if (event.values.length > 4) {
	    		float[] truncatedRotationVector = new float[4];
	    	    System.arraycopy(event.values, 0, truncatedRotationVector, 0, 4);
	    	    update(truncatedRotationVector);
	    	} else {
	    		 update(event.values);
	    	}
	    }
	}
	
	private void update(float[] vectors) {
        float[] rotationMatrix = new float[9];
        SensorManager.getRotationMatrixFromVector(rotationMatrix, vectors);
        int worldAxisX = SensorManager.AXIS_X;
        int worldAxisZ = SensorManager.AXIS_Z;
        float[] adjustedRotationMatrix = new float[9];
        SensorManager.remapCoordinateSystem(rotationMatrix, worldAxisX, worldAxisZ, adjustedRotationMatrix);
        float[] orientation = new float[3];
        SensorManager.getOrientation(adjustedRotationMatrix, orientation);
        float pitch = orientation[1] * FROM_RADS_TO_DEGS;
        float roll = orientation[2] * FROM_RADS_TO_DEGS;
//        Log.v("Pitch + Roll", Float.toString(pitch) + "  " + Float.toString(roll) );

        String newtilt;
        if ( -40<pitch && pitch<40 ){
            if (60<roll && roll<120){
                newtilt="left";
                if (!newtilt.equals(oldtilt)){
                    oldtilt = newtilt;
                    Log.v("tilt",newtilt);
                }
            }else if(-120< roll && roll<-60){
                newtilt="right";
                if (!newtilt.equals(oldtilt)){
                    oldtilt = newtilt;
                    Log.v("tilt",newtilt);
                }
            }else if(-45 < roll && roll< 45){
                newtilt="portrait";
                if (!newtilt.equals(oldtilt)){
                    oldtilt = newtilt;
                    Log.v("tilt",newtilt);
                }
            }
        }
    }

}

This code snippet is based on the code of William J. Francis a great developer at TechRepublic.

Full sample app can be found at: http://www.techrepublic.com/article/pro-tip-use-android-sensors-to-detect-orientation-changes

Cheers!