在iOS 5中向下拖动UIView

// 获取要动画的UIView
let dragView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
view.addSubview(dragView)

// 创建一个CABasicAnimation，并将其与UIView的layer关联
let animation = CABasicAnimation(keyPath: "transform.translation.y")
animation.fromValue = NSNumber(value: 0)
animation.toValue = NSNumber(value: 100)
animation.duration = 0.5
animation.autoreverses = true
animation.repeatCount = 10

// 将CABasicAnimation添加到UIView的layer中
dragView.layer.add(animation, forKey: "drag animation")

let animation = CAKeyframeAnimation(keyPath: "transform.translation")
animation.values = [NSValue(cgPoint: CGPoint(x: 0, y: 0)), NSValue(cgPoint: CGPoint(x: 50, y: 100)), NSValue(cgPoint: CGPoint(x: 100, y: 100))]
animation.keyTimes = [0, 0.5, 1]
animation.duration = 1
animation.fillMode = kCAFillModeForwards
animation.isRemovedOnCompletion = false

dragView.layer.add(animation, forKey: "drag animation")