如果点击后退按钮，导航栏标题颜色不会改变

Question

Changing the color of the title in the navigation bar does not work if back button is tapped.

There is a UINavigationController.

Its rootViewController is VC1. The color of the title in the navigation bar is set to red.

VC1 pushes VC2. The color of the title in the navigation bar is set to green.

When VC2 is popped, the color of the title in the navigation bar is set to red.

If the back button is used to pop VC2, the title of the navigation bar does not change to red and remains green.

If the swipe back gesture is used to pop VC2, the title of the navigation bar changes to red as expected.

The navigation controller is its own delegate. Using the navigationController(_:willShow:animated) method, the color of the tile in the navigation bar is set.

extension NavigationController: UINavigationControllerDelegate {
    func navigationController(
        _ navigationController: UINavigationController,
        willShow viewController: UIViewController,
        animated: Bool
        ) {
        let attributes: [NSAttributedString.Key: Any] = [
            .foregroundColor: viewController is VC1 ? UIColor.red : UIColor.green
        ]
        navigationBar.titleTextAttributes = navigationBar.titleTextAttributes?.merging(attributes) { $1 }
    }
}

Expected- After the VC2 is popped, the color of the title in the navigation bar should change to red.

Actual- After the VC2 is popped, the color of the title in the navigation bar remains green.

Can anyone point out how to solve this issue, so that the color of the title in the navigation bar becomes red after VC2 is popped out?

Answer 1

Do this in ViewDidLoad()

let image = UIImage(named: "back")
        self.navigationController?.navigationBar.backIndicatorImage = image
        self.navigationController?.navigationBar.backIndicatorTransitionMaskImage = image
        self.navigationItem.title = "Servicos"
        self.navigationController?.navigationBar.titleTextAttributes = [NSAttributedString.Key.foregroundColor: UIColor.white]

Answer 2

If both of the viewController has large title enabled. Otherwise use titleTextAttributes . It is required that the two of your ViewControllers' UINavigationController's delegate is NavigationController

extension NavigationController: UINavigationControllerDelegate {
    func navigationController(_ navigationController: UINavigationController, willShow viewController: UIViewController, animated: Bool) {
        if let _ = viewController as? ToViewController {
            let textAttributes = [NSAttributedString.Key.foregroundColor:UIColor.red]
            navigationController.navigationBar.largeTitleTextAttributes = textAttributes
        } else {
            let textAttributes = [NSAttributedString.Key.foregroundColor:UIColor.green]
            navigationController.navigationBar.largeTitleTextAttributes = textAttributes
        }
    }
}

This worked for me. Both of my viewControllers has large title.

Answer 3

Have you tried changing navigationBar tint color?