Changing back button in iOS 7 disables swipe to na

Question

I have an iOS 7 app where I am setting a custom back button like this:

    UIImage *backButtonImage = [UIImage imageNamed:@"back-button"];
    UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];

    [backButton setImage:backButtonImage forState:UIControlStateNormal];
    backButton.frame = CGRectMake(0, 0, 20, 20);

    [backButton addTarget:self
                   action:@selector(popViewController)
         forControlEvents:UIControlEventTouchUpInside];

    UIBarButtonItem *backBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:backButton];
    viewController.navigationItem.leftBarButtonItem = backBarButtonItem;

But this disables the iOS 7 "swipe left to right" gesture to navigate to the previous controller. Does anyone know how I can set a custom button and still keep this gesture enabled?

EDIT: I tried to set the viewController.navigationItem.backBarButtonItem instead, but this doesn't seem to show my custom image.

Answer 1

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

This is from http://stuartkhall.com/posts/ios-7-development-tips-tricks-hacks, but it causes several bugs:

1. Push another viewController into the navigationController when swiping in from the left edge of the screen;
2. Or, swipe in from the left edge of the screen when the topViewController is popping up from the navigationController;

e.g. When the rootViewController of navigationController is showing, swipe in from the left edge of the screen, and tap something(QUICKLY) to push anotherViewController into the navigationController, then

• The rootViewController does not respond any touch event;
• The anotherViewController will not be shown;
• Swipe from the edge of the screen again, the anotherViewController will be shown;
• Tap the custom back button to pop the anotherViewController, crash!

So you must implement UIGestureRecognizerDelegate method in self.navigationController.interactivePopGestureRecognizer.delegate like this:

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
    if (gestureRecognizer == navigationController.interactivePopGestureRecognizer) {
        return !navigationController.<#TODO: isPushAnimating#> && [navigationController.viewControllers count] > 1;
    }
    return YES;
}

Answer 2

I had a similar problem where I was assigning the current view controller as the delegate for the interactive pop gesture, but would break the gesture on any views pushed, or views underneath the view in the nav stack. The way I solved this was to set the delegate in -viewDidAppear, then set it to nil in -viewWillDisappear. That allowed my other views to work correctly.

Answer 3

IMPORTANT: This is a hack. I would recommend taking a look at this answer.

Calling the following line after assigning the leftBarButtonItem worked for me:

self.navigationController.interactivePopGestureRecognizer.delegate = self;

Edit: This does not work if called in init methods. It should be called in viewDidLoad or similar methods.

Answer 4

Here is swift3 version of Nick H247's answer

class NavigationController: UINavigationController {
  override func viewDidLoad() {
    super.viewDidLoad()
    if responds(to: #selector(getter: interactivePopGestureRecognizer)) {
      interactivePopGestureRecognizer?.delegate = self
      delegate = self
    }
  }

  override func pushViewController(_ viewController: UIViewController, animated: Bool) {
    if responds(to: #selector(getter: interactivePopGestureRecognizer)) {
      interactivePopGestureRecognizer?.isEnabled = false
    }
    super.pushViewController(viewController, animated: animated)
  }
}

extension NavigationController: UINavigationControllerDelegate {
  func navigationController(_ navigationController: UINavigationController, didShow viewController: UIViewController, animated: Bool) {
    interactivePopGestureRecognizer?.isEnabled = (responds(to: #selector(getter: interactivePopGestureRecognizer)) && viewControllers.count > 1)
  }
}

extension NavigationController: UIGestureRecognizerDelegate {}

Answer 5

RootView

override func viewDidAppear(_ animated: Bool) {
    self.navigationController?.interactivePopGestureRecognizer?.isEnabled = false
}

ChildView

override func viewDidLoad() {
    self.navigationController?.interactivePopGestureRecognizer?.isEnabled = true
    self.navigationController?.interactivePopGestureRecognizer?.delegate = self
} 

extension ChildViewController: UIGestureRecognizerDelegate {}

Answer 6

Use this logic to keep enable or disable the swipe gesture..

- (void)navigationController:(UINavigationController *)navigationController
       didShowViewController:(UIViewController *)viewController
                    animated:(BOOL)animate
{
    if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)])
    {
        if (self.navigationController.viewControllers.count > 1)
        {
            self.navigationController.interactivePopGestureRecognizer.enabled = YES;
        }
        else
        {
            self.navigationController.interactivePopGestureRecognizer.enabled = NO;
        }
    }
}