使用一个手指旋转UIView的代码

Code Snippet for rotating a view with single finger.

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

    UITouch *touch = [touches anyObject];

    touch1=[touch locationInView:self.superview];

    touch2=[touch previousLocationInView:self.superview];

    

    

}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event

{

    

    UITouch *touch = [touches anyObject];

    CGPoint currentTouch1=[touch locationInView:self.superview];

    CGPoint currentTouch2=[touch previousLocationInView:self.superview];

    

    CGFloat previousAngle = atan2(touch2.y - touch1.y, touch2.x - touch1.x) * 180 / 3.14;

    CGFloat currentAngle = atan2(currentTouch2.y - currentTouch1.y,currentTouch2.x - currentTouch1.x) * 180 / 3.14;

    

    CGFloat angleToRotate = currentAngle - previousAngle;

    

    CGAffineTransform transform = CGAffineTransformRotate(self.transform, angleToRotate*3.14/180);

    

    self.transform = transform;

    touch1 = currentTouch1;

    touch2 = currentTouch2;

    

    

}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event

{

    

}