UINavigationController Interactive Pop Gesture Not

问题:

So I have a navigation controller in my built for iOS 7 app. The titleView is visible, as well as the back button and navigation bar its self. For some reason, the interactive pop gesture (swipe from the left edge) isn't working. Nothing happens. When I log the gesture, it is not nil. Is there anything special I have to do to enable this functionality? What could cause it not to work?

回答1:

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
    }

}

回答2:

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

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

    return YES;

}

回答3:

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.

回答4:

You can put this line in the viewDidLoad method.

self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>)self;

回答5:

The more worked out answer was both Aaron and lojals

First Customise the Navigation controller and then put this code in the class

In ViewDidload put this line:

self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>)self;

And in class write this function

-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer { return YES;}

回答6:

In Swift 4, I have a UITableView inside my view controller, I solved this issue with:

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

回答7:

Maybe someone may find this helpful.

If you want to hide the navigation bar but use normal swipe gestures to go back and other navigation controller features, you should use: (navigationBar)

self.navigationController?.navigationBar.isHidden = true

If you want to disable navigation bar (hide navigation bar, disable swipe for back) but want to push viewcontroller you should use: (isNavigationBarHidden)

self.navigationController?.isNavigationBarHidden = true

Update 7-DEC-2018:

In case that your first controller use hidden navigation bar, but next childs use navigation bar, when you come back to base view controller you will see a black bar in transition in place of navigation bar. This will be fixed very easy if you use in first viewcontroller(father):

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    self.navigationController?.setNavigationBarHidden(true, animated: animated)
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    self.navigationController?.setNavigationBarHidden(false, animated: animated)
}