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

Question

When dismissing various view controllers using UIModalPresentationCustom, the screen turns black after the view controller is dismissed, as if all the view controllers had been removed from the view hierarchy.

The transitioning delegate is set properly, the animationControllerForPresentedController is asked for and passed correctly, and the transition is completed once the animation is over.

This exact code works perfectly when compiled with the iOS 7 SDK, but is broken when compiled with iOS 8b5

I'm using Xcode 6 GM and getting similar behavior except the screen is white (my window has a white background color). Code works fine in iOS 7. I inspected the view with Reveal and the window is just empty. — Mark, Sep 18 '14 at 12:02
Xcode 6 GM here too and seeing the same behavior. Using the built-in view exploder, I find only a UIWindow and UITextEffectsWindow after the transition. Everything else is gone. — Kevin Sliech, Sep 19 '14 at 13:27

score 192 · Accepted Answer · answered Sep 26 '14 at 00:42

192

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
}

answered Sep 26 '14 at 00:42

denvdancsk

3,033
2
26
41

13

This is the correct answer and should be accepted. There was a bug in iOS 7, which they fixed in iOS 8. The solution above works perfectly on iOS 7 and 8. Thanks DJSK for pointing this out, spent some time figuring out how do I get a blank screen. – Stas Zhukovskiy Sep 29 '14 at 22:22
1

I concur with @StasZhukovskiy. This solves the issue. One remaining problem I find is that the presented/dismissed ViewController leaks in iOS7.0, although not 7.1 or 8... – Mike Pollard Oct 01 '14 at 10:27
3

Apparently this is not the correct answer - according to the `UIViewControllerContextTransitioning` header we should use `-viewForKey` method to get the views. Unfortunately with the presentation style of `UIModalPresentationCustom` causes `-viewForkey` to return nil in some cases which is apparently the desired behavior.... Check out `bcherry`'s answer over [here](http://stackoverflow.com/questions/24338700/from-view-controller-disappears-using-uiviewcontrollercontexttransitioning). – DanZimm Feb 17 '15 at 02:32
I don't know but by some reason I don't see view of controller that presented my view controller after dimiss – Matrosov Oleksandr Mar 03 '15 at 19:47
1

@DanZimm using [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey].view or [transitionContext viewForKey:UITransitionContextFromView] doesn't matter. They are the exact same thing. The issue when using a custom modal transition, is that (in iOS8) if you add the fromView to the animation controller, it's not returned to the original hierarchy when the animation completes. You can either manually return it afterwards or you can choose to not add it at all. – denvdancsk Mar 10 '15 at 15:08
@DJSK I was quoting Apple's docs. The header specifically says not to use the `viewControllerForKey:UITransitionContextFromViewControllerKey` to get the view. – DanZimm Mar 10 '15 at 16:09
Isn't that only if your building for iOS8 only and won't work if you want to target iOS7 and iOS8 together? – denvdancsk Mar 10 '15 at 17:45
1

@DJSK Does your post answer my other question [there](http://stackoverflow.com/q/29436076/1670830)? Thanks – Colas Apr 07 '15 at 11:42
Yes, this solutions applies and in my opinion is the easiest. However, DanZimm's solution works as well but you would need to add an if statement in your animation controller object class to determine what version of iOS the app is running on. Then add the views to the animation controller object using the View Controller Transition Keys for iOS7 and the View Transition Keys for iOS8. – denvdancsk Apr 07 '15 at 19:20
This is the exact fix for the problem I was having. The problem I was facing was calling dismiss view controller with or without custom animation after presenting from a custom animation would cause the screen to just go back. Removing adding both the presented and presenting fixed the issue. It even caused multiple views to constantly stack with out dismissing. This fix was great. Thank you! – lostAtSeaJoshua Jun 06 '16 at 18:35

score 21 · Answer 2 · edited Jun 03 '19 at 07:51

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.

This is definitely the correct way to achieve this if you're developing for specific versions of iOS like 8 or greater. The answer I provided is just an easy way to achieve the same thing without having to check or be specific, while also accommodating iOS7. — denvdancsk, Feb 17 '16 at 06:32
This answer is correct. Solve problems on ios12. Thought this is a system bug. — Tepmnthar, Apr 27 '21 at 08:58

score 5 · Answer 3 · answered Aug 31 '14 at 08:47

5

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

answered Aug 31 '14 at 08:47

billbai

143
1
6

3

This is not a bug in Xcode or iOS 8. The correct solution is provided by DJSK. – Stas Zhukovskiy Sep 29 '14 at 22:24

score 2 · Answer 4 · edited Sep 16 '14 at 15:47

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];
}];

score 2 · Answer 5 · answered Sep 28 '14 at 01:00

2

Perhaps the view hierarchy is buggy with new Xcode or maybe it's a little different is iOS8. This code worked for me. Add it while dismissing the controller in animateTransition: transitionContext method.

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

answered Sep 28 '14 at 01:00

Gautam Jain

2,913
30
25

1

It may not a bug in iOS but in our own code. Did you set modalPresentationStyle to UIModalPresentationCustom, but not implemented the presentationControllerForPresentedViewController method? See here: http://stackoverflow.com/a/25655575/466965 – Lcsky Dec 05 '15 at 02:24

score 0 · Answer 6 · answered Mar 26 '15 at 04:02

Quick Tip: Make sure your "From" UIViewController is what you're expecting.

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

Had a similar bug in my code in the past. You can easily pull out the right "From" VC context.

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

score 0 · Answer 7 · answered Nov 05 '16 at 17:02

I had the same problem, and what caused the problem for me is that I wasn't setting the toViewController's final frame. See the following example from http://www.appcoda.com/custom-view-controller-transitions-tutorial/

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
    })
}

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

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