Rotation repetition animation - ios

Question

I'd like to animate a UIImageView left and right. My goal is quite simple:
I have an image, I'd like to rotate it slightly to the left with an angle of .pi/8 and then from that rotated position, rotate it back to -pi/8. I want to repeat these rotations three times and stop. The image has to be in a non-rotated state initially.
I was able to achieve it by doing this:
UIView.animate(withDuration: 0.3, delay: 0.4, options: [], animations: {
self.imageView.rotate(angle: .pi/9)
}, completion: { _ in
UIView.animate(withDuration: 0.3, delay: 0.0, options: [], animations: {
self.imageView.rotate(angle: -.pi/7)
}, completion: { _ in
UIView.animate(withDuration: 0.3, delay: 0.0, options: [], animations: {
self.imageView.rotate(angle: .pi/9)
}, completion: { _ in
UIView.animate(withDuration: 0.3, delay: 0.0, options: [], animations: {
self.imageView.rotate(angle: -.pi/7)
}, completion: { _ in
UIView.animate(withDuration: 0.3, delay: 0.0, options: [], animations: {
self.imageView.rotate(angle: .pi/9)
}, completion: { _ in
UIView.animate(withDuration: 0.3, delay: 0.0, options: [], animations: {
self.imageView.rotate(angle: -.pi/7)
}, completion: {_ in
UIView.animate(withDuration: 0.3, delay: 0.0, options: [], animations: {
self.giftImageView.rotate(angle: .pi/10.5)
})})})})})})})})
However, I believe there is a simpler way to do it but I can't figure it out and the research isn't leading to any simpler solution. After some trial and error, I got to .pi/10.5 to have the image view centered and to not look tilted.
I'd much appreciate your help for a simpler way, thanks!

Answer 1

here is rotation extension function
extension UIView {
func rotation(isClockWise:Bool) {
let rotation : CABasicAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
if isClockWise {
rotation.toValue = NSNumber(value: Double.pi / 8)
} else {
rotation.toValue = NSNumber(value: -Double.pi / 8)
}
rotation.duration = 1 // 1 second duration change it to 0.3 or whatever
rotation.isCumulative = true
rotation.repeatCount = 3
self.layer.add(rotation, forKey: "rotationAnimation")
}
}
then you need to do some work in controller
class ViewController:UIViewController {
var timer = Timer()
var isClockWise = false
var rotationCount = 0
let imageView = UIImageView()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .orange
timer = Timer.scheduledTimer(timeInterval: 0.3, target: self, selector: #selector(rotationHandle), userInfo: nil, repeats: true)
}
#objc
func rotationHandle() {
rotationCount += 1
if isClockWise {
imageView.rotation(isClockWise: true)
} else {
imageView.rotation(isClockWise: false)
}
isClockWise.toggle()
if rotationCount == 6 {
timer.invalidate()
imageView.layer.removeAllAnimations()
imageView.transform = .identity
}
}
}