涟漪动画ripple

摘要: 关于iOS基础动画的第一篇,使用swift实现一些layer动画.

ripple是涟漪的意思,接下来实现的动画你将一块石头投入静止的水面所看到的一样.

ripple动画是通过一个scale动画和alpha动画组合起来的, 最后别忘了设置重复次数哦.

func addRippleAnimation() {
let shapeLayer = CAShapeLayer()
shapeLayer.lineWidth = 0.2
shapeLayer.strokeColor = UIColor.blueColor().CGColor
let width: CGFloat = 2.0
let path = UIBezierPath(roundedRect: CGRectMake(0, 0, width, width), cornerRadius: width/2.0)
shapeLayer.path = path.CGPath
shapeLayer.fillColor = UIColor.clearColor().CGColor
shapeLayer.position = view.center
shapeLayer.bounds = path.bounds
//添加layer
view.layer.addSublayer(shapeLayer)

//scale animation
let scalAni = CABasicAnimation(keyPath: "transform.scale")
scalAni.fromValue = NSValue(CATransform3D: CATransform3DIdentity)
scalAni.toValue = NSValue(CATransform3D: CATransform3DMakeScale(60, 60, 1))

//alpha animation
let alphaAni = CABasicAnimation(keyPath: "opacity")
alphaAni.fromValue = 1
alphaAni.toValue  = 0

let groupAni = CAAnimationGroup()
groupAni.animations  = [scalAni, alphaAni]
groupAni.duration = 1.0
groupAni.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)
groupAni.removedOnCompletion = false
groupAni.repeatCount = HUGE //重复次数为无限大

shapeLayer.addAnimation(groupAni, forKey: nil)

}