Core Animation - modify animation property

Question

I have animation

 func startRotate360() {
    let rotation : CABasicAnimation = CABasicAnimation(keyPath: \"transform.rotation.z\")
    rotation.fromValue =          


        

Answer 1

Maybe this is not the best solution but it works, as you say you can not modify properties of the CABasicAnimation once is created, also we need to remove the rotation.repeatCount = Float.greatestFiniteMagnitude, if notCAAnimationDelegatemethodanimationDidStop` is never called, with this approach the animation can be stoped without any problems as you need

step 1: first declare a variable flag to mark as you need stop animation in your custom class

var needStop : Bool = false

step 2: add a method to stopAnimation after ends

func stopAnimation()
{
    self.needStop = true
}

step 3: add a method to get your custom animation

func getRotate360Animation() ->CAAnimation{
    let rotation : CABasicAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
    rotation.fromValue = 0
    rotation.toValue =  Double.pi * 2
    rotation.duration = 1
    rotation.isCumulative = true
    rotation.isRemovedOnCompletion = false
    return rotation
}

step 4: Modify your startRotate360 func to use your getRotate360Animation() method

func startRotate360() {
    let rotationAnimation = self.getRotate360Animation()
    rotationAnimation.delegate = self
    self.layer.add(rotationAnimation, forKey: "rotationAnimation")
}

step 5: Implement CAAnimationDelegate in your class

extension YOURCLASS : CAAnimationDelegate
{

    func animationDidStop(_ anim: CAAnimation, finished flag: Bool) {
        if(anim == self.layer?.animation(forKey: "rotationAnimation"))
        {
            self.layer?.removeAnimation(forKey: "rotationAnimation")
            if(!self.needStop){
                let animation = self.getRotate360Animation()
                animation.delegate = self
                self.layer?.add(animation, forKey: "rotationAnimation")
            }
        }
    }
}

This works and was tested

Hope this helps you