How to enable back/left swipe gesture in UINavigat

问题:

I got the opposite issue from here. By default in iOS7, back swipe gesture of UINavigationController's stack could pop the presented ViewController. Now I just uniformed all the self.navigationItem.leftBarButtonItem style for all the ViewControllers.

Here is the code:

self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithImage:LOADIMAGE(@"back_button") style:UIBarButtonItemStylePlain target:self action:@selector(popCurrentViewController)];

after that, the navigationController.interactivePopGestureRecognizer is disabled. How could I make the pop gesture enabled without removing the custom leftBarButtonItem?

Thanks!

回答1:

First set delegate in viewDidLoad:

self.navigationController.interactivePopGestureRecognizer.delegate = self;

And then disable gesture when pushing:

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated {
    [super pushViewController:viewController animated:animated];
    self.interactivePopGestureRecognizer.enabled = NO;
}

And enable in viewDidDisappear:

self.navigationController.interactivePopGestureRecognizer.enabled = YES;

回答2:

It works for me when I set the delegate

self.navigationController.interactivePopGestureRecognizer.delegate = self;

and then implement

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

回答3:

it works for me Swift 3:

    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldBeRequiredToFailBy otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        return true
    }

and in ViewDidLoad:

    self.navigationController?.interactivePopGestureRecognizer?.delegate = self
    self.navigationController?.interactivePopGestureRecognizer?.isEnabled = true

回答4:

You need to handle two scenarios:

1. When you're pushing a new view onto the stack
2. When you're showing the root view controller

If you just need a base class you can use, here's a Swift 3 version:

import UIKit

final class SwipeNavigationController: UINavigationController {

    // MARK: - Lifecycle

    override init(rootViewController: UIViewController) {
        super.init(rootViewController: rootViewController)
    }

    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)

        delegate = self
    }

    required init?(coder aDecoder: NSCoder) { 
        super.init(coder: aDecoder) 

        delegate = self 
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        // This needs to be in here, not in init
        interactivePopGestureRecognizer?.delegate = self
    }

    deinit {
        delegate = nil
        interactivePopGestureRecognizer?.delegate = nil
    }

    // MARK: - Overrides

    override func pushViewController(_ viewController: UIViewController, animated: Bool) {
        duringPushAnimation = true

        super.pushViewController(viewController, animated: animated)
    }

    // MARK: - Private Properties

    fileprivate var duringPushAnimation = false

}

// MARK: - UINavigationControllerDelegate

extension SwipeNavigationController: UINavigationControllerDelegate {

    func navigationController(_ navigationController: UINavigationController, didShow viewController: UIViewController, animated: Bool) {
        guard let swipeNavigationController = navigationController as? SwipeNavigationController else { return }

        swipeNavigationController.duringPushAnimation = false
    }

}

// MARK: - UIGestureRecognizerDelegate

extension SwipeNavigationController: UIGestureRecognizerDelegate {

    func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        guard gestureRecognizer == interactivePopGestureRecognizer else {
            return true // default value
        }

        // Disable pop gesture in two situations:
        // 1) when the pop animation is in progress
        // 2) when user swipes quickly a couple of times and animations don't have time to be performed
        return viewControllers.count > 1 && duringPushAnimation == false
    }
}

If you end up needing to act as a UINavigationControllerDelegate in another class, you can write a delegate forwarder similar to this answer.

Adapted from source in Objective-C: https://github.com/fastred/AHKNavigationController

回答5:

This is the best way to enable/ disable swipe to pop view controller in iOS 10, Swift 3 :

For First Screen [ Where you want to Disable Swipe gesture ] :

class SignUpViewController : UIViewController,UIGestureRecognizerDelegate {

//MARK: - View initializers
override func viewDidLoad() {
    super.viewDidLoad()
}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    swipeToPop()
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

func swipeToPop() {

    self.navigationController?.interactivePopGestureRecognizer?.isEnabled = true;
    self.navigationController?.interactivePopGestureRecognizer?.delegate = self;
}

func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {

    if gestureRecognizer == self.navigationController?.interactivePopGestureRecognizer {
        return false
    }
    return true
} }

For middle screen [ Where you want to Enable Swipe gesture ] :

class FriendListViewController : UIViewController {

//MARK: - View initializers
override func viewDidLoad() {

    super.viewDidLoad()
    swipeToPop()
}

func swipeToPop() {

    self.navigationController?.interactivePopGestureRecognizer?.isEnabled = true;
    self.navigationController?.interactivePopGestureRecognizer?.delegate = nil;
} }

回答6:

Swift 3:

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    self.navigationController?.interactivePopGestureRecognizer?.delegate = self
}

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
    return true
}

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer) -> Bool {
    return (otherGestureRecognizer is UIScreenEdgePanGestureRecognizer)
}

回答7:

Setting a custom back button disable the swipe back feature.

The best thing to do to keep it is to subclass UINavigationViewController and set itself as the interactivePopGestureRecognizer delegate; then you can return YES from gestureRecognizerShouldBegin to allow the swipe back.

For example, this is done in AHKNavigationController

And a Swift version here: https://stackoverflow.com/a/43433530/308315

回答8:

This answer, but with storyboard support.

class SwipeNavigationController: UINavigationController {

    // MARK: - Lifecycle

    override init(rootViewController: UIViewController) {
        super.init(rootViewController: rootViewController)
    }

    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?) {
        super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)

        self.setup()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        self.setup()
    }

    private func setup() {
        delegate = self
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        // This needs to be in here, not in init
        interactivePopGestureRecognizer?.delegate = self
    }

    deinit {
        delegate = nil
        interactivePopGestureRecognizer?.delegate = nil
    }

    // MARK: - Overrides

    override func pushViewController(_ viewController: UIViewController, animated: Bool) {
        duringPushAnimation = true

        super.pushViewController(viewController, animated: animated)
    }

    // MARK: - Private Properties

    fileprivate var duringPushAnimation = false
}

回答9:

For those who are still having trouble with this, try separating the two lines as below.

override func viewDidLoad() {
    self.navigationController!.interactivePopGestureRecognizer!.delegate = self
    ...

override func viewWillAppear(_ animated: Bool) {
    self.navigationController!.interactivePopGestureRecognizer!.isEnabled = true
    ...

Obviously, in my app,

interactivePopGestureRecognizer!.isEnabled

got reset to false before the view was shown for some reason.