CODEWITHSUNDEEP
iosswiftuinavigationcontroller
Kashif
Kashif

Reputation: 4632

How to get navigation back button title?

self.navigationItem.backBarButtonItem!.title causes fatal error: unexpectedly found nil while unwrapping an Optional value while clearly there is a back button with title string in it in my view controller

How do I get the back button's title string?

Upvotes: 0

Views: 476

Answers (1)

beyowulf
beyowulf

Reputation: 15331

When you reference self.navigationItem.backBarButtonItem you should be aware that this is the bar button item that will be used in the navigation bar when self is not the topViewController but rather immediately below the topViewController. That is self.navigationItem.backBarButtonItem is not the button currently visible when self is the topViewController but when another view controller is pushed on top of it.

You should also be aware:

When this property is nil, the navigation item uses the value in its title property to create an appropriate back button.

Meaning that self.navigationItem.backBarButtonItem can be nil and still have a title. See here

If you want to know what text is being used with the back button You could could say something like:

extension UINavigationController {
    var backButtonText: String? {
        guard let self.viewControllers.count > 1 else { return nil }
        let viewController = self.viewControllers[self.viewControllers.count - 2]
        return viewController.navigationItem.backBarButtonItem?.title ?? viewController.title
    }
}

Which could be called like:

print(self.navigationController?.backButtonText ?? "No back button title")

Upvotes: 1

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