Custom UINavigationController transitions cannot be made interactive

Originator:Roben.Kleene
Number:rdar://17814789 Date Originated:07/25.2014
Status:Open Resolved:
Product:iOS 8 Beta 4 Product Version:Version 8.0 (12A4331d)
Classification:Serious Bug Reproducible:Always
 
Summary:
UINavigationController's call the "interactionControllerForAnimationController" delegate method *after* starting a transition and therefore makes it impossible to use interactive transitions with navigation controllers.

Steps to Reproduce:
1. Open the attached sample app on iOS 8 (this is the sample app from [objc.io's tutorial](http://www.objc.io/issue-5/view-controller-transitions.html) on [View Controller transitions](https://github.com/objcio/issue5-view-controller-transitions) with one edit to add an assert to highlight the bug.
2. Tap the "Push" button
3. With the "Hello, World" screen visible, do a left to right swipe gesture
4. After performing #3 the app will crash on the "The transition should be interactive" assert.

(The above works on iOS 7.)

Expected Results:
`UINavigationController` interactive animations should be possible.

Actual Results:
`UINavigationController` interactive animations are not possible.

Comments


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