之前埋了个坑，要介绍一下这个CAReplicatorLayer的，结果一直也没写，今天想起来还是简单写一下吧。
直接上代码：
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
let subView = UIView(frame: CGRect(x: 100, y: 100, width: 100, height: 100))
subView.backgroundColor = UIColor.lightGray
view.addSubview(subView)
let animatedLayer = CALayer()
animatedLayer.frame = CGRect(x: 0, y: 45, width: 10, height: 10)
animatedLayer.cornerRadius = 5
let animation = CABasicAnimation(keyPath: "transform.scale")
animation.fromValue = NSNumber(value: 1)
animation.toValue = NSNumber(value: 0.5)
animation.duration = 1.9
animation.autoreverses = false
animation.repeatCount = Float.greatestFiniteMagnitude
animatedLayer.backgroundColor = UIColor.red.cgColor
animatedLayer.add(animation, forKey: "scale")
let replicatorLayer = CAReplicatorLayer()
replicatorLayer.frame = subView.bounds
replicatorLayer.addSublayer(animatedLayer)
replicatorLayer.instanceCount = 20
replicatorLayer.instanceDelay = 0.1
replicatorLayer.instanceTransform = CATransform3DMakeRotation(CGFloat.pi*2/20, 0, 0, 1)
subView.layer.addSublayer(replicatorLayer)
}
简单说一下，就是只要创建一个** CAReplicatorLayer**，然后在这个layer上添加子layer，就可以根据需要复制出相应的layer（复制的是子layer），如果子layer有动画，它复制出的也会执行动画，这就很有灵性了，看一下每个属性都是做什么的：
instanceCount：需要复制的数量
instanceDelay：复制出来的layer执行动画跟上一个执行动画的延迟
instanceTransform：复制出的layer的排列规则
😄
indicator.gif
