IOS CAKeyFrameAnimation 实现动态位移

 1 override func viewDidLoad() {
 2 super.viewDidLoad()
 3 // Do any additional setup after loading the view,
 typically from a nib.
 4
 5 let imageView = UIImageView(frame：CGRect(x：40,
 y：80, width：64, height：64))
 6 imageView.image = UIImage(named：“star”)
 7 self.view.addSubview(imageView)
 8
 9 let animation =
 CAKeyframeAnimation(keyPath：“position”)
 10
 11 let point1 = CGPoint(x：40, y：80)
 12 let point2 = CGPoint(x：280, y：80)
 13 let point3 = CGPoint(x：60, y：300)
 14 let point4 = CGPoint(x：280, y：300)
 15
 16 animation.values = [NSValue(cgPoint：point1),
 NSValue(cgPoint：point2),
 17 NSValue(cgPoint：point3), NSValue(cgPoint：point4)]
 18 animation.keyTimes = [NSNumber(value：0.0),
 NSNumber(value：0.4),
 19 NSNumber(value：0.6), NSNumber(value：1.0)]
 20
 21 animation.delegate = self
 22 animation.duration = 5.0
 23
 24 imageView.layer.add(animation, forKey：“Move”)
 25 }
 26 func animationDidStart(_ anim：CAAnimation) {
 27 print(“The animation starts”)
 28 }
 29
 30 func animationDidStop(_ anim：CAAnimation,
 finished flag：Bool) {
 31 print(“End of the animation”)
 32 }