gistfile1.swift

import UIKit
import XCPlayground
let view = UIView(frame: CGRect(x: 0, y: 0, width: 500, height: 500))
let shapeLayer = CAShapeLayer()
let size:CGFloat = 52
let rect = CGRect(x: view.bounds.midX - size/2, y: view.bounds.midY-size/2, width: size, height: size)
shapeLayer.path = UIBezierPath(ovalInRect: rect).CGPath
shapeLayer.fillColor = UIColor.clearColor().CGColor
shapeLayer.strokeColor = UIColor.darkGrayColor().CGColor
shapeLayer.lineWidth = 3
shapeLayer.strokeStart = 0
shapeLayer.strokeEnd = 1
view.layer.addSublayer(shapeLayer)
XCPShowView("view", view)

let beginTime = CACurrentMediaTime()
let anim1 = CABasicAnimation(keyPath: "strokeEnd")
anim1.fromValue = 0
anim1.toValue = 1.0
anim1.duration = 2.0
anim1.beginTime = CACurrentMediaTime()

let anim2 = CABasicAnimation(keyPath:"strokeStart")
anim2.fromValue = 0
anim2.toValue = 0.1
anim2.duration = 2.0
anim2.beginTime = CACurrentMediaTime() + 2.0

let group = CAAnimationGroup()
group.animations = [anim1, anim2]
group.duration = 4.0

//shapeLayer.addAnimation(anim1, forKey:nil)
//shapeLayer.addAnimation(anim2, forKey:nil)
shapeLayer.addAnimation(group, forKey: nil)