我如何处理像begintouches这样的事件......只需要触摸图像或点击按钮就可以完成某些操作

 -(BOOL) beginTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event
{
        CGPoint touchPoint = [touch locationInView:self];
        float dx = touchPoint.x - disc.center.x;
        float dy = touchPoint.y - disc.center.y;
        deltaAngle = atan2(dy,dx);
        startTransform = disc.transform;
}
 -(BOOL) beginTrackingWithTouch:(UITouch *)touc