swift4 CAKeyframeAnimation not work - animation

Question

I used layer animations on a view, but I couldn't work at swift4
My view override the layerClass property
public override class var layerClass: Swift.AnyClass {
return CoordLayer.self
}
And custom key creation CAKeyframeAnimation
let animation = CAKeyframeAnimation(keyPath: "moveX")
animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionDefault)
animation.values = values
animation.keyTimes = times.map{ NSNumber(value: $0) }
animation.duration = duration
animation.fillMode = kCAFillModeForwards
animation.delegate = self
self.layer.add(animation, forKey: "moveX")
The CoordLayer Class
class CoordLayer: CALayer {
override class func needsDisplay(forKey key: String) -> Bool {
if "moveX" == key {
return true // ..... swift4 No call ....
}
return super.needsDisplay(forKey: key)
}
}
override func display(){
// .......some custom operations......
// ....... swift4 No call .......
}
}
The view has no animation effect swift4

Answer 1

KeyFrameAnimation is working as expected in swift 4 also :
Please check the implementation, you need some correction in your implementation.
Let's see it.
Define Controller :
import UIKit
// Controller
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
addView()
}
private let myView : MyView = {
let view = MyView()
view.translatesAutoresizingMaskIntoConstraints = false // enable auto layout
view.backgroundColor = .red
return view
}() // execute closure
private func addView() {
view.addSubview(myView)
NSLayoutConstraint.activate([
myView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor), // leading
myView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor), // top
myView.widthAnchor.constraint(equalTo: view.safeAreaLayoutGuide.widthAnchor, multiplier: 0.2), // width = 20 % of view width
myView.heightAnchor.constraint(equalTo: myView.widthAnchor, multiplier: 1.0) // height = width
])
}
}
Define MyView :
// View
class MyView : UIView {
// draw view
override func draw(_ rect: CGRect) {
super.draw(rect)
}
// layerClass
public override class var layerClass: Swift.AnyClass {
return CoordLayer.self
}
}
Define CoordLayer :
// Layer
class CoordLayer : CALayer {
override func display() {
// some custom operations
backgroundColor = UIColor.red.cgColor // to visualize
customAnimation() // add animation
print("Display")
}
override class func needsDisplay(forKey key: String) -> Bool {
if key == "transform.translation.x" {
return true
}
return super.needsDisplay(forKey: key)
}
// add animation
private func customAnimation() {
let values = [100,150,200,250]
let times : [NSNumber] = [0.0, 0.25, 0.5, 1.0] // not necessary always
let animation = CAKeyframeAnimation(keyPath: "transform.translation.x") // moving view along x direction
animation.timingFunctions = [CAMediaTimingFunction(name: kCAMediaTimingFunctionDefault)] // array of timing function
animation.values = values // taking the animated property values for animation
animation.keyTimes = times // define the timing array
animation.duration = 5.0 // CFTimeInterval
animation.isRemovedOnCompletion = false // do not remove the animation effect, no state changes.
animation.fillMode = kCAFillModeForwards
animation.delegate = self
// add animation on coordLayer
self.add(animation, forKey: "animation")
}
}
Animation Delegate :
extension CoordLayer : CAAnimationDelegate {
func animationDidStart(_ anim: CAAnimation) {
print("Animation started")
}
func animationDidStop(_ anim: CAAnimation, finished flag: Bool) {
print("Animation stopped")
}
}
Correction in your implementation :
(1) Instead of "moveX", use "transform.translation.x"
(2) Give some animation duration, animation.duration = 5.0 // CFTimeInterval
(3) animation.isRemovedOnCompletion = false , so that after animation, view will not move it's beginning position.
You can add animation logic in MyView also because you are adding animation on layer. Animation Delegate can be conformed by MyView.(it's upto you).
You can check out the implementation here.
Thanks. :-)