iOS 8 - Screen blank after dismissing view controller with custom presentation

This is the kind of question that the high-votes & accepted answer mislead people. Long words short.

Firstly, don't use UIModalPresentationCustom, it's not what it sounds like. (detail)

Secondly, there is a new method to retrieve from/to Views in animateTransition, don't use something like 'fromVC.view' anymore. (why)

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)

Now the black screen should go away.

I added the code below to the transition completion block and it fixed it for me.

[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];
}];

It seems I encountered the same issue, I'm using Xcode 6 beta5.

I searched with Google and found someone else has this same issue, and they said this is serious a bug in iOS 8, so hope Apple can fix this soon.

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

This is because you are most likely adding both the presenting

[transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey]

and the presented

[transitionContext viewControllerForKey:UITransitionContextToViewControllerKey]

view controllers to your containerView in the (void)animateTransition:(id )transitionContext method of your animation controller. Since you are using a custom modal presentation, the presenting view controller is still shown beneath the presented view controller. Now since it's still visible you don't need to add it to the container view. Instead only add the presented view controller to the containerView. Should look something like this inside of your animateTransition: method

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
}