Swift 自定义转场动画 （没有封装）

Swift 自定义转场 （自认为很重要）做一个类似于微信右上角加号点击弹出的功能

控制器以模态的形式弹出的时候 后面的视图会消失要想不消失需要设置一个属性 ： 控制器的modalPresentationStyle 设置为.Custom

 // MARK:- 事件监听的函数extension HomeViewController {@objc private func titleBtnClick(titleBtn : TitleButton) {    // 1.改变按钮的状态    titleBtn.selected = !titleBtn.selected    // 2.创建弹出的控制器    let popoverVc = PopoverViewController()    // 3.设置控制器的modal样式    popoverVc.modalPresentationStyle = .Custom    // 4.设置转场的代理    popoverVc.transitioningDelegate = self    // 弹出控制器    presentViewController(popoverVc, animated: true, completion: nil)}}// 自定义转场代理代码extension HomeViewController : UIViewControllerTransitioningDelegate {func presentationControllerForPresentedViewController(presented: UIViewController, presentingViewController presenting: UIViewController, sourceViewController source: UIViewController) -> UIPresentationController? {    return WDPresentationController(presentedViewController: presented, presentingViewController: presenting)}}// 目的:自定义弹出的动画func animationControllerForPresentedController(presented: UIViewController, presentingController presenting: UIViewController, sourceController source: UIViewController) -> UIViewControllerAnimatedTransitioning? {    isPresented = true    return self}// 目的:自定义消失的动画func animationControllerForDismissedController(dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {    isPresented = false    return self}}// MARK:- 弹出和消失动画代理的方法extension HomeViewController : UIViewControllerAnimatedTransitioning {/// 动画执行的时间func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {    return 0.5}/// 获取`转场的上下文`:可以通过转场上下文获取弹出的View和消失的View// UITransitionContextFromViewKey : 获取消失的View// UITransitionContextToViewKey : 获取弹出的Viewfunc animateTransition(transitionContext: UIViewControllerContextTransitioning) {    isPresented ? animationForPresentedView(transitionContext) : animationForDismissedView(transitionContext)}/// 自定义弹出动画private func animationForPresentedView(transitionContext: UIViewControllerContextTransitioning) {    // 1.获取弹出的View    let presentedView = transitionContext.viewForKey(UITransitionContextToViewKey)!    // 2.将弹出的View添加到containerView中    transitionContext.containerView()?.addSubview(presentedView)    // 3.执行动画    presentedView.transform = CGAffineTransformMakeScale(1.0, 0.0)    presentedView.layer.anchorPoint = CGPointMake(0.5, 0)    UIView.animateWithDuration(transitionDuration(transitionContext), animations: { () -> Void in        presentedView.transform = CGAffineTransformIdentity        }) { (_) -> Void in            // 必须告诉转场上下文你已经完成动画            transitionContext.completeTransition(true)    }}/// 自定义消失动画private func animationForDismissedView(transitionContext: UIViewControllerContextTransitioning) {    // 1.获取消失的View    let dismissView = transitionContext.viewForKey(UITransitionContextFromViewKey)    // 2.执行动画    UIView.animateWithDuration(transitionDuration(transitionContext), animations: { () -> Void in        dismissView?.transform = CGAffineTransformMakeScale(1.0, 0.00001)        }) { (_) -> Void in            dismissView?.removeFromSuperview()            // 必须告诉转场上下文你已经完成动画            transitionContext.completeTransition(true)    }}}