Two Finger Rotation For Osmdroid Mapview

I'm trying to make two finger rotation for my offline maps using osmdroid. I'm new to using maps for android. I have a geoTIFF, I'm planning to extract info using NDK and later sen

Solution 1:

Have you taken a look at the OpenStreetMapViewer sample app? There is the RotationGestureOverlay overlay in there that specifically shows how to do this. It isn't as smooth as I would like it, but it will do the job.

Solution 2:

For simplicity, use the following classes:

publicclassRotationGestureDetector {

publicinterfaceRotationListener {
    publicvoidonRotate(float deltaAngle);
}

protectedfloat mRotation;
private RotationListener mListener;

publicRotationGestureDetector(RotationListener listener) {
    mListener = listener;
}

privatefloatrotation(MotionEvent event) {
    double delta_x = (event.getX(0) - event.getX(1));
    double delta_y = (event.getY(0) - event.getY(1));
    double radians = Math.atan2(delta_y, delta_x);
    return (float) Math.toDegrees(radians);
}

publicvoidonTouch(MotionEvent e) {
    if (e.getPointerCount() != 2)
        return;

    if (e.getActionMasked() == MotionEvent.ACTION_POINTER_DOWN) {
        mRotation = rotation(e);
    }

    float rotation = rotation(e);
    float delta = rotation - mRotation;
    mRotation += delta;
    mListener.onRotate(delta);
}

}

And

publicclassRotationGestureOverlayextendsOverlayimplementsRotationGestureDetector.RotationListener
{

privatefinal RotationGestureDetector mRotationDetector;
private RotationGestureDetector.RotationListener rotationListener;


publicRotationGestureOverlay(Context context, RotationGestureDetector.RotationListener rotationListener)
{
    super(context);
    this.rotationListener = rotationListener;
    mRotationDetector = newRotationGestureDetector(this);
}

@OverridepublicbooleanonTouchEvent(MotionEvent event, MapView mapView)
{
    if (this.isEnabled()) {
        mRotationDetector.onTouch(event);
    }
    returnsuper.onTouchEvent(event, mapView);
}

@OverridepublicvoidonRotate(float deltaAngle)
{
    rotationListener.onRotate(deltaAngle);
}

@Overridepublicvoiddraw(Canvas canvas, MapView mapView, boolean b) {

}

}

Add the overlay:

mapView.getOverlays().add(new RotationGestureOverlay(context,this);