Question

This only accours if you are presenting in a view controller that is managed by a navigation controller.

The reproduction steps are:

1 – Present a view controller using UIModalPresentationCurrentContext

self.definesPresentationContext = YES;
ViewController* viewController = [[ViewController alloc] init];
viewController.modalPresentationStyle = UIModalPresentationCurrentContext;
[presentOnViewController presentViewController:viewController animated:YES completion:nil];

2 – Present a view controller over the top using the default full screen presentation style

ViewController* viewController = [[ViewController alloc] init];
[self presentViewController:viewController animated:YES completion:nil];

3 – Dismiss the top presented view controller (the full screen one)

[self dismissViewControllerAnimated:YES completion:nil];

Now the problem is the 2nd view controller (presented using UIModalPresentationCurrentContext) disappears. Also it is impossible to present another view controller using UIModalPresentationCurrentContext, because the system thinks its still there.

Answer 1

I believe the issue is a bug in the framework. As mentioned it only occurs when the presenting in a view controller managed by a navigation controller. There is a nasty work around which uses the containment API. It creates a dummy view controller which views are presented from. The steps are:

1 – When presenting a view in context who’s parent is a navigation controller, use a dummy view controller:

- (void)presentInContext
{
    UIViewController* presentOnViewController = self;

    if ([self.parentViewController isKindOfClass:[UINavigationController class]])
    {
        // Work around - Create an invisible view controller
        presentOnViewController = [[DummyViewController alloc] init];
        presentOnViewController.view.frame = self.view.frame;

        // Containment API
        [self addChildViewController:presentOnViewController];
        [self.view addSubview:presentOnViewController.view];
        [presentOnViewController didMoveToParentViewController:self];

        presentOnViewController.definesPresentationContext = YES;
    }

    ViewController* viewController = [[ViewController alloc] init];
    viewController.modalPresentationStyle = UIModalPresentationCurrentContext;
    [presentOnViewController presentViewController:viewController animated:YES completion:nil];
}

2 – When dismissing the view controller tidy up

- (void)dismissSelf
{
    __weak UIViewController* presentingViewController = self.presentingViewController;

    [self dismissViewControllerAnimated:YES completion:^{

        // Remove the dummy view controller
        if ([presentingViewController isKindOfClass:[DummyViewController class]])
        {
            [presentingViewController willMoveToParentViewController:nil];
            [presentingViewController.view removeFromSuperview];
            [presentingViewController removeFromParentViewController];
        }
    }];
}

Thats it… The fix is dirty, but does the trick with no visual flicker.