Xcode9学习笔记60 - UIView视图卷曲动画的制作

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        let rect = CGRect(x: 58, y: 40, width: 200, height: 200)
        let imageView = UIImageView(frame: rect)
        let image = UIImage(named: "Pic")
        imageView.image = image//给图像视图指定要显示的图片
        imageView.tag = 1//设置图像视图的标识值，以方便后期对图像视图的调用
        
        self.view.addSubview(imageView)
        
        let button = UIButton(type: UIButtonType.system)//初始化一个按钮对象，点击按钮时播放动画
        button.frame = CGRect(x: 58, y: 400, width: 200, height: 44)
        button.backgroundColor = UIColor.lightGray
        button.setTitle("Tap", for: UIControlState())
        button.addTarget(self, action: #selector(ViewController.playAnimation), for: UIControlEvents.touchUpInside)
        
        self.view.addSubview(button)
    }
    
    @objc func playAnimation() {
        UIView.beginAnimations(nil, context: nil)//发出开始动画的请求
        UIView.setAnimationCurve(.easeOut)//设置动画的播放速度为淡入淡出
        UIView.setAnimationDuration(5)//设置动画时长5秒
        UIView.setAnimationBeginsFromCurrentState(true)//设置动画从当前状态开始播放
        let view = self.view.viewWithTag(1)//通过标识值找到之前创建的图像视图，作为动画的载体
        UIView.setAnimationTransition(.curlUp, for: view!, cache: true)//设置动画类型为翻转动画
        UIView.commitAnimations()//调用视图的提交动画方法，标志着动画块的结束
    }