Animation stops after segueing to different view controller

Question

I have an animation in my app that basically just makes a UIButton grow and shrink to make it obvious to the user that they should tap.

The problem is that while it works fine when the view first appears, it doesn't work if I go to a different view controller (with a segue) and then return (nothing happens).

Here is my code:

override func viewWillAppear(animated: Bool) {
    expandAnimation()
}

func expandAnimation() {
    var animation = CABasicAnimation(keyPath: "transform.scale")
    animation.toValue = NSNumber(float: 0.9)
    animation.duration = 1
    animation.repeatCount = 100
    animation.autoreverses = true
    animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
    appDevButton.layer.addAnimation(animation, forKey: nil)
}

I'm sure it's a simple fix, but I couldn't find any info online.

Answer 1

Remove the animation from the button when you leave the view,

    override func viewDidDisappear(animated: Bool) {
        super.viewDidDisappear(animated)
        appDevButton.layer.removeAllAnimations()
    }