UIView Infinite 360 degree rotation animation?

Question

I'm trying to rotate a UIImageView 360 degrees, and have looked at several tutorials online. I could get none of them working, without the UIView either stopping, or jumping to a new position.

• How can I achieve this?

The latest thing I've tried is:

[UIView animateWithDuration:1.0
                      delay:0.0
                    options:0
                 animations:^{
                     imageToMove.transform = CGAffineTransformMakeRotation(M_PI);
                 } 
                 completion:^(BOOL finished){
                     NSLog(@"Done!");
                 }];

But if I use 2*pi, it doesn't move at all (since it's the same position). If I try to do just pi (180 degrees), it works, but if I call the method again, it rotates backwards.

EDIT:

[UIView animateWithDuration:1.0
                      delay:0.0
                    options:0
                 animations:^{
                     [UIView setAnimationRepeatCount:HUGE_VALF];
                     [UIView setAnimationBeginsFromCurrentState:YES];
                     imageToMove.transform = CGAffineTransformMakeRotation(M_PI);
                 } 
                 completion:^(BOOL finished){
                     NSLog(@"Done!");
                 }];

doesn't work either. It goes to 180 degrees, pauses for a split second, then resets back to 0 degrees before it starts again.

Answer 1

There are following different ways to perform 360 degree animation with UIView.

Using CABasicAnimation

var rotationAnimation = CABasicAnimation()
rotationAnimation = CABasicAnimation.init(keyPath: "transform.rotation.z")
rotationAnimation.toValue = NSNumber(value: (Double.pi))
rotationAnimation.duration = 1.0
rotationAnimation.isCumulative = true
rotationAnimation.repeatCount = 100.0
view.layer.add(rotationAnimation, forKey: "rotationAnimation")

Here is an extension functions for UIView that handles start & stop rotation operations:

extension UIView {

    // Start rotation
    func startRotation() {
        let rotation = CABasicAnimation(keyPath: "transform.rotation.z")
        rotation.fromValue = 0
        rotation.toValue = NSNumber(value: Double.pi)
        rotation.duration = 1.0
        rotation.isCumulative = true
        rotation.repeatCount = FLT_MAX
        self.layer.add(rotation, forKey: "rotationAnimation")
    }

    // Stop rotation
    func stopRotation() {
        self.layer.removeAnimation(forKey: "rotationAnimation")
    }
}

Now using, UIView.animation closure:

UIView.animate(withDuration: 0.5, animations: { 
      view.transform = CGAffineTransform(rotationAngle: (CGFloat(Double.pi)) 
}) { (isAnimationComplete) in
    // Animation completed 
}

Answer 2

let val = CGFloat(M_PI_2)

UIView.animate(withDuration: 1, delay: 0, options: [.repeat, .curveLinear], animations: {
        self.viewToRotate.transform = self.viewToRotate.transform.rotated(by: val)
})