Moving an Image in circular motion based on touch events in android

Question

I am trying to move an ImageView (not rotate). The movement is supposed to be on the edge of a circle. This circle is also an image view.

based on the onTouch, ACTI

Answer 1

1. calculate the center Point of the Circle
2. get the current touch point
3. calculate the angle between center and new touch point
4. Calculate the point on the circle using angle and radius of circle (x = r * cos(angle), y = r * sin(angle)).
5. Reset the image position to the new point.

To get the angle use the below equation

deltaY = P2_y - P1_y
deltaX = P2_x - P1_x
angleInDegrees = arctan(deltaY / deltaX) * 180 / PI

//Code inside ACTION_MOVE case
mInitialX = event.getX();
mInitialY = event.getY();
float deltaX = circleCenter.x - mInitialX;
float deltaY = circleCenter.y - mInitialY;
double angleInRadian = Math.atan2(yDiff, xDiff);
PointF pointOnCircle = new PointF();
pointOnCircle.x = circleCenter.x + ((float)(circleRadius*(Math.cos(angleInRadian))));
pointOnCircle.y = circleCenter.y + ((float)(circleRadius*(Math.cos(angleInRadian))));