从VC取得View很容易,但有些情况下我们需要从View反向获取VC.
不过在一些特殊的场合,Cocoa库帮我们想的很周到,比如在自定义View过渡动画的时候:
func animateTransition(transitionContext: UIViewControllerContextTransitioning) { }
系统在回调我们的animateTransition方法时,会传入一个context参数,从它我们可以轻松取得参与动画的toView,fromView以及它们对应的VC:
let toView = transitionContext.viewForKey(UITransitionContextToViewKey)! let toViewController = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)! let fromView = transitionContext.viewForKey(UITransitionContextFromViewKey)! let fromViewController
