Animate spinning image in Swift - ios

Question

I have a image that I would like to keep spinning if a button is pressed, until I call an action to stop the spinning. I tried these websites: https://www.andrewcbancroft.com/2014/10/15/rotate-animation-in-swift/ I had to made chances to the delegation, it crashes when I try to changed it
and https://bencoding.com/2015/07/27/spinning-uiimageview-using-swift/ just does not spin when I call the action. Thank you. Code is here below:
Andrewcbancroft.com:
extension UIView {
func rotate360Degrees(duration: CFTimeInterval = 1.0, completionDelegate: AnyObject? = nil) {
let rotateAnimation = CABasicAnimation(keyPath: "transform.rotation")
rotateAnimation.fromValue = 0.0
rotateAnimation.toValue = CGFloat(M_PI * 2.0)
rotateAnimation.duration = duration
if let delegate: AnyObject = completionDelegate {
rotateAnimation.delegate = delegate //<- error "Cannot assign value of type 'AnyObject' to type 'CAAnimationDelegate?'"
}
self.layer.add(rotateAnimation, forKey: nil)
}
}
Trying to cast delegate as! CAAnimationDelegate will crash the application with error code Could not cast value of type 'test.ViewController' (0x1074a0a60) to 'CAAnimationDelegate' (0x10cede480) when trying to rotate the image.
Bending.com:
extension UIView {
func startRotating(duration: Double = 1) {
let kAnimationKey = "rotation"
if self.layer.animation(forKey: kAnimationKey) == nil {
let animate = CABasicAnimation(keyPath: "transform.rotation")
animate.duration = duration
animate.repeatCount = Float.infinity
animate.fromValue = 0.0
animate.toValue = Float(M_PI * 2.0)
self.layer.add(animate, forKey: kAnimationKey)
}
}
func stopRotating() {
let kAnimationKey = "rotation"
if self.layer.animation(forKey: kAnimationKey) != nil {
self.layer.removeAnimation(forKey: kAnimationKey)
}
}
}
When trying to call my image view to start rotating in my viewDidLoad method, nothing happens.

Answer 1

Errors explained:
You're passing the delegate in as AnyObject
func rotate360Degrees(duration: CFTimeInterval = 1.0, completionDelegate: AnyObject? = nil)
AnyObject doesn't conform to CAAnimationDelegate, so you can't use it as the delegate.
If you're certain you're passing in a controller that can be a proper delegate, then cast it to the right kind of delegate:
if let delegate = completionDelegate as? CAAnimationDelegate {
rotateAnimation.delegate = delegate
}
If you're doing this and it's crashing:
rotateAnimation.delegate = completionDelegate as! CAAnimationDelegate
Then you're not passing in a controller that conforms to CAAnimationDelegate
It might be simpler to not pass the delegate in at all and assign it outside of the extension.