iOS 8-在关闭具有自定义演示的视图控制器后屏幕空白

使用关闭各种视图控制器时，关闭视图控制器后UIModalPresentationCustom，屏幕将变黑，就好像所有视图控制器都已从视图层次结构中删除一样。

正确设置了过渡委托，要求并正确传递animationControllerForPresentedController，并且一旦动画结束，过渡就完成了。

使用iOS 7 SDK编译时，此确切的代码可以完美地工作，但使用iOS 8b5编译时，该代码会损坏

这是因为您很可能同时添加两个演示文稿

[transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey]

和提出

[transitionContext viewControllerForKey:UITransitionContextToViewControllerKey]

在您的动画控制器的（void）animateTransition：（id）transitionContext方法中查看容器的控制器。由于您使用的是自定义模式演示，因此呈现视图控制器仍显示在呈现的视图控制器下方。现在，由于它仍然可见，因此您无需将其添加到容器视图中。而是仅将提供的视图控制器添加到containerView。应该在animateTransition：方法内部看起来像这样

UIView *containerView = [transitionContext containerView];
UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];

// Boolean value to determine presentation or dismissal animation
if (self.presenting){        
    [transitionContext.containerView addSubview:toViewController.view];
    // Your presenting animation code
} else {
    // Your dismissal animation code
}

这种高票赞成的答案会误导人们。长话短。

首先，不要使用UIModalPresentationCustom，这听起来并不像。（详细）

其次，有一种新方法可以在animateTransition中从视图中检索/到视图，不再使用诸如'fromVC.view'之类的东西。（为什么）

UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toVC = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView *fromView = [transitionContext viewForKey:UITransitionContextFromViewKey];
UIView *toView = [transitionContext viewForKey:UITransitionContextToViewKey];

//swift
let fromVC = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey)
let toVC = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)
let fromView = transitionContext.viewForKey(UITransitionContextFromViewKey)
let toView = transitionContext.viewForKey(UITransitionContextToViewKey)

现在黑屏应该消失了。

似乎我遇到了相同的问题，我正在使用Xcode 6 beta5。

我在Google上进行搜索，发现其他人也遇到了同样的问题，他们说这是iOS 8中的一个严重错误，因此希望Apple可以尽快解决此问题。

https://github.com/TeehanLax/UIViewController-Transitions-Example/issues/5

我将下面的代码添加到过渡完成块中，并为我修复了它。

[UIView animateWithDuration:[self transitionDuration:transitionContext] animations: ^{
    // Animation code

 } completion: ^(BOOL finished) {
     // More of your code

     // Add the following line before completing the transition
    [[[UIApplication sharedApplication] keyWindow] sendSubviewToBack:toViewController.view];

    // Complete the transition
    [transitionContext completeTransition:YES];
}];

可能视图层次结构与新的Xcode无关，或者与iOS8有所不同。这段代码对我有用。在animateTransition：transitionContext方法中关闭控制器时添加它。

[[UIApplication sharedApplication].keyWindow addSubview:toViewController.view];
toViewController.view.userInteractionEnabled = YES;

快速提示：确保您的“ From” UIViewController是您所期望的。

    NSLog(@" FROM vc %@" , [[transitionContext  viewControllerForKey:UITransitionContextFromViewControllerKey] description]);

过去，我的代码中也有类似的错误。您可以轻松地提取正确的“ From” VC上下文。

  UIViewController *fromVC = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];  
  fromView =  [[[fromVC childViewControllers] firstObject]  view];

我有同样的问题，对我来说造成问题的是我没有设置toViewController的最后一帧。请参见http://www.appcoda.com/custom-view-controller-transitions-tutorial/中的以下示例

func animateTransition(transitionContext: UIViewControllerContextTransitioning) {

    let fromViewController = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey)!
    let toViewController = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)!
    let finalFrameForVC = transitionContext.finalFrameForViewController(toViewController)
    let containerView = transitionContext.containerView()
    let bounds = UIScreen.mainScreen().bounds
    toViewController.view.frame = CGRectOffset(finalFrameForVC, 0, bounds.size.height)
    containerView.addSubview(toViewController.view)

    UIView.animateWithDuration(transitionDuration(transitionContext), delay: 0.0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.0, options: .CurveLinear, animations: {
        fromViewController.view.alpha = 0.5
        toViewController.view.frame = finalFrameForVC
    }, completion: {
        finished in
        transitionContext.completeTransition(true)
        fromViewController.view.alpha = 1.0
    })
}