Reference to presentingViewController from custom transition

Question

I have setup a custom transition which is setup similar to this tutorial here.

What I am trying to do now is update a BOOL on the (below) UIViewController. This is the controller that presents the controller on top.

How do I get access/a pointer to the below controller? I have tried self.presentingViewController but this is pointing to a UINavigationController.

Custom Transition Info
The bottom controller is the UIViewControllerTransitioningDelegate. The controllers are linked by a segue. The following is in the prepareForSegue:

self.animationController = [[MESGuessGameTurnZoomAnimation alloc] init];
UIViewController *destVC = segue.destinationViewController;    
destVC.transitioningDelegate = self;

When the destination view controller is presented the user can click Back which simply runs the following (at present) to return to the original view controller:

[self dismissViewControllerAnimated:YES completion:nil];

Answer 1

It sounds like you're trying to pass data back from the presentedVC to the presentingVC. If that's the case, the approach is the same whether you're using the new iOS 7 custom animated transitions or not.

You have 2 options, again the same if you use a standard transition or a custom transition.

1. Use a delegate pattern when you click Back. That way the presentingVC calls dismiss and can access the presentedVC and any of it's properties.

   How do I set up a simple delegate to communicate between two view controllers?

2. Use an unwind segue. This accomplishes the same thing but using storyboards. https://developer.apple.com/library/ios/technotes/tn2298/_index.html

You can access both view controllers in prepareForSegue: and in the animationController's animateTransition: method using the transitioningContext but I think you're just talking about transferring back data and that can be done using one of the above approaches.