Rotating animation shown at final position only iOS swift - swift

Question

I am trying to implement custom activity indicator which is simple rotating UIImageView. I have next code
import Foundation
import UIKit
class CatSpinnerAnimation: UIView {
let catImageView: UIImageView = {
let catImageView = UIImageView()
catImageView.image = UIImage(named: "CatDateIcon-1024")
catImageView.translatesAutoresizingMaskIntoConstraints = false
return catImageView
}()
func startRotating(superView: UIView) {
superView.addSubview(catImageView)
UIApplication.shared.beginIgnoringInteractionEvents()
catImageView.centerXAnchor.constraint(equalTo: superView.centerXAnchor).isActive = true
catImageView.centerYAnchor.constraint(equalTo: superView.centerYAnchor).isActive = true
catImageView.widthAnchor.constraint(equalToConstant: 50).isActive = true
catImageView.heightAnchor.constraint(equalToConstant: 50).isActive = true
let rotate = CGAffineTransform(rotationAngle: CGFloat.pi)
UIView.animate(withDuration: 5.0) {
self.catImageView.transform = rotate
}
}
func stopRotating(superView: UIView) {
UIApplication.shared.endIgnoringInteractionEvents()
catImageView.removeFromSuperview()
}
}
In my ViewControllers I instantiate an instance of this class and call its function
let catSpinnerAnimation = CatSpinnerAnimation()
catSpinnerAnimation.startRotating(superView: view)
But this doesn't show rotating animation at all, just my ImageView in final position (rotated for 189 degrees). I tried many types of animation but still don't have necessary result. I would appreciate any explanation of correct behavior of rotating animations

Answer 1

I think you might need to let the view be added to the view hierarchy first before you can animate it. Try wrapping your call to UIView.animate() in a call to DispatchQueue.main.asyncAfter(deadline: .now() + .01) {}
That would let your view be added to the view hierarchy and get rendered before you submit your animation.