使用动画将按钮旋转不到180度

Question

I'm trying to rotate a button when it is pressed by 45 degrees. The problem I have is that if the button is rotating 180 degrees it works fine, but if I choose an angle less than this the button still rotates but it jumps about the screen rather than rotating at its current location. Is there any reason why this happens for angles less than 180 and how can I fix this?

This is the code I have.

Thanks

- (void)viewDidLoad
{
angle = 45;
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}

- (IBAction)Rotate:(id)sender {

[UIView beginAnimations:nil context:nil];
[UIView setAnimationDelegate:self];
[UIView setAnimationDuration:2];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];


CGAffineTransform rotateTrans =
CGAffineTransformMakeRotation(angle * M_PI/180);


angle = angle + 45;

self.btnRotate.transform = rotateTrans;

[UIView commitAnimations];

}

Answer 1

I've discovered the problem was down to autolayout being used in interface builder. Every time the object turned onto its side autolayout would reposition it on screen.