Flipping x animation with repetition after a certain duration - ios

Question

I was trying to do a "flip x animation" for a UIButton. I have seen some documentation on how to do this animation but i couldn't find how to do it with repetition. For example, i want to flip the image of the UIButton and change it after a time interval of 5 sec with repetition.
Any help? Thanks.

Answer 1

You can use CAAnimationGroup to group an array of animations. Total animation for whole animationGroup is 6.0, flip animation takes place for 1.0 second. so remaining 5.0 seconds act as delay here.
EDIT: CATransaction.setCompletionBlock can be used but it will only call completion after all animations are completed. So now the flip will occur only for one time and on completion you will receive completion call, and update image view and initiate flip animation again.
Like this
imageView.flip {
// update imageView and call it again.
}
extension UIView {
func flip(completion: #escaping ()->()) {
CATransaction.begin()
CATransaction.setCompletionBlock {
// completion code here
completion()
}
let animationGroup = CAAnimationGroup()
animationGroup.duration = 6.0
animationGroup.repeatCount = 1
let easeInOut = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
let animation = CABasicAnimation(keyPath: "transform")
animation.duration = 1.0
animation.autoreverses = true
animation.fromValue = CATransform3DIdentity
animation.toValue = NSValue(caTransform3D: CATransform3DMakeRotation(CGFloat(M_PI), 0, 1, 0))
animation.timingFunction = easeInOut
animationGroup.animations = [animation]
layer.anchorPoint = CGPoint(x: 0.5, y: 0.5)
layer.add(animationGroup, forKey: "flip")
CATransaction.commit()
}
}