UINavigationController Interactive Pop Gesture Not Working?

Look at this response and comments. All you have to do is set your navigation controller's interactive pop gesture recognizer's delegate to nil:

self.navigationController.interactivePopGestureRecognizer.delegate = nil;

Setting it to a casted self to id<UIGestureRecognizerDelegate> also works because all methods in the protocol are optional, but I think setting the delegate to nil is more appropriate in this case.

I have found that when using custom back buttons, the interactive pop gesture stops working (my take is that Apple cannot foresee how your custom back button will behave, so they disable the gesture).

To fix this, as other mentioned before, you can set the interactivePopGestureRecognizer.delegate property to nil.

In Swift, this can easily be done across your entire application by adding an extension for UINavigationController like this:

extension UINavigationController {

    override public func viewDidLoad() {
        super.viewDidLoad()
        interactivePopGestureRecognizer?.delegate = nil
    }

}

Updated answer

Seems like setting the delegate to nil causes the app UI to freeze in some scenarios (eg. when the user swipes left or right on the top view controller of the navigation stack).

Because gestureRecognizerShouldBegin delegate method cannot be handled in an extension, subclassing UINavigationController seems like the best solution:

class NavigationController: UINavigationController, UIGestureRecognizerDelegate {

    /// Custom back buttons disable the interactive pop animation
    /// To enable it back we set the recognizer to `self`
    override func viewDidLoad() {
        super.viewDidLoad()
        interactivePopGestureRecognizer?.delegate = self
    }

    func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        return viewControllers.count > 1
    }

}

Eh, looks like I just had to set the gesture delegate and implement the following:

-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {

    return YES;

}