CODEWITHSUNDEEP
iosswiftuinavigationbarios13popviewcontroller
tibi95
tibi95

Reputation: 51

iOS 13 and UINavigationBarDelegate::shouldPop()

I've upgraded the Xcode to 11, and I found some issues on iOS13 Simulators/real devices of our iOS app with shouldPop() method from UINavigationBarDelegate protocol:

This protocol has 4 methods, 3 of them are working fine, only this shouldPop() doesn't work anymore. If I run the app on previous iOS version devices/Simulators, everything is fine, shouldPop() is called but if I run the app on iOS13, shouldPop() is not called. Because on previous iOS version everything is ok, 3 out of 4 methods of the protocol are called and I din't find in documentation that shouldPop() is not-supported/deprecated, it seems to be a bug, but I am not sure.

Do you guys have any idea about this?

Thank you, Tibi.

private class DummyNavigationController: UINavigationController, UINavigationControllerDelegate, UINavigationBarDelegate {
    var rootViewController: UIViewController? {
        didSet {
            self.delegate = self
        }
    }

    func navigationBar(_ navigationBar: UINavigationBar, didPush item: UINavigationItem) {
        // working
    }

    func navigationBar(_ navigationBar: UINavigationBar, shouldPush item: UINavigationItem) -> Bool {
        // working
        return true
    }

    func navigationBar(_ navigationBar: UINavigationBar, didPop item: UINavigationItem) {
        // working
    }

    func navigationBar(_ navigationBar: UINavigationBar, shouldPop item: UINavigationItem) -> Bool {
        // not working
        return true
    }
}

private class DummyViewController: UIViewController {
    convenience init(_ showBackText: Bool) {
        self.init()
        if !showBackText {
            self.navigationItem.title = ""
        }
    }
}

class OpenModalWithNavigation {

    static func present(viewController: UIViewController,
                        parentViewController: UIViewController,
                        showBackText: Bool = false,
                        presentationStyle: UIModalPresentationStyle = .overCurrentContext,
                        transitionStyle: UIModalTransitionStyle = .crossDissolve) {

        let navController = DummyNavigationController()
        navController.rootViewController = parentViewController
        navController.pushViewController(DummyViewController(showBackText), animated: false)
        navController.pushViewController(viewController, animated: false)
        navController.modalPresentationStyle = presentationStyle
        navController.modalTransitionStyle = transitionStyle
        parentViewController.present(navController, animated: true, completion: nil)
    }
}

Edit: After some investigation in our big code, yes, we call popViewController() from a custom "back" button. It's somehow similar with the code below: if I put in DummyNavigationController via OpenModalWithNavigation.present() a qqq instance, the shouldPop() is not fired.

class qqq: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        self.view.backgroundColor = UIColor.green

        let button = UIButton(type: .custom)
        let backImage = UIImage(named: "back")
        button.setImage(backImage, for: .normal)
        button.frame = CGRect(x: 0, y: 0, width: 30, height: 30)
        button.addTarget(self, action: #selector(self.goBack), for: .touchUpInside)

        let backButton = UIBarButtonItem(customView: button)
        self.navigationItem.leftBarButtonItem = backButton
    }

    @objc func goBack() {
        self.navigationController?.popViewController(animated: true)
    }
}

Also, the simplified form of qqq (see below), it will not work... It seems to be related to popViewController()

class qqq: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(2), execute: {
            self.navigationController?.popViewController(animated: true)
        })
    }   
}

If I press the default back button, everything is ok, shouldPop() is called; not when we call popViewController() - this is happening only on an iOS13 running device/simulator; for pre-iOS13: everything is fine.

Upvotes: 1

Views: 2392

Answers (5)

user3589502
user3589502

Reputation: 101

I have experienced the same issue when using an extension on UINavigationController in the simulator.

I have therefore decided to use a concrete class as the delegate. Since I am not making very many of them, maximally three or four per storyboard. Setting the Custom class field in the storyboard doesn't seem too bad.

Upvotes: 0

Marco M
Marco M

Reputation: 1235

In iOS 13.4 it only works if implemented in the same file of the controller that uses it, could be in a separate extension but must be the same file... that is. The other three methods still continue to work as before, as they should.

At least this is how I solved the problem, I had the implementation in a generic extension inside a framework that stopped working.

Upvotes: 1

El Horrible
El Horrible

Reputation: 176

This isn't answer to your question but if it helps anyone...

shouldPop wasn't called for me in a simulator but it worked on a device. I had shouldPop method declared in an extension of UINavigationController. I removed it from extension and put it in UINavigationController subclass and now it works in simulator too.

Upvotes: 0

Paolo Musolino
Paolo Musolino

Reputation: 634

It seems that it's not working properly only on the iOS simulator. If you try to run on the device, everything is fine.

Upvotes: 1

Amrit
Amrit

Reputation: 301

Remove private access modifier from Navigation controller class declaration.

class DummyNavigationController: UINavigationController, UINavigationControllerDelegate, UINavigationBarDelegate {
    var rootViewController: UIViewController? {
        didSet {
            self.delegate = self
        }
    }

    func navigationBar(_ navigationBar: UINavigationBar, didPush item: UINavigationItem) {
        // working
    }

    func navigationBar(_ navigationBar: UINavigationBar, shouldPush item: UINavigationItem) -> Bool {
        // working
        return true
    }

    func navigationBar(_ navigationBar: UINavigationBar, didPop item: UINavigationItem) {
        // working
    }

    func navigationBar(_ navigationBar: UINavigationBar, shouldPop item: UINavigationItem) -> Bool {
        // working
        return true
    }
}

Private access restricts the use of an entity/class to the enclosing declaration, and to extensions of that declaration that are in the same file.

If you still face issue let me know.

Upvotes: 0

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