Canceling interactive UINavigationController pop gesture does not call UINavigationControllerDelegate methods

Question

If you drag the edge of a UIViewController to begin an interactive pop transition within a UINavigationController, the UIViewController un

Answer 1

I translated @Dima's answer to Swift for my project:

func navigationController(navigationController: UINavigationController, willShowViewController viewController: UIViewController, animated: Bool) {

    transitionCoordinator()?.notifyWhenInteractionEndsUsingBlock { context in
        guard context.isCancelled(), let fromViewController = context.viewControllerForKey(UITransitionContextFromViewControllerKey) else { return }

        self.navigationController(self, willShowViewController: fromViewController, animated: animated)

        let animationCompletion: NSTimeInterval = context.transitionDuration() * Double(context.percentComplete())

        let delayTime = dispatch_time(DISPATCH_TIME_NOW, Int64(1 * Double(NSEC_PER_SEC)))
        dispatch_after(delayTime, dispatch_get_main_queue()) {
            self.navigationController(self, didShowViewController: fromViewController, animated: animated)
        }            
    }

    /* Your normal behavior goes here */

}

Note that I don't check for the existence of an implementation of navigationController(_:didShowViewController:animated:), although I believe this is checked at compile-time in Swift, and that you'll get a compiler error if you attempt to call this when it's unimplemented.