iOS UINavigationBar button remains faded after seg

Question

In my app I have multiple view controllers, and most have a right-hand-side UIBarButtonItem with direct "show" segue actions attached.

Having segued to another view and then pressed the '< Back' button, the original button item remains faded out, although still otherwise usable.

This only appears to happen under iOS 11.2.

I can't see any setting that could be doing this, and in at least one of the cases where this happens there's no specific segue unwinding nor viewDidAppear handling. I'd post some code, but AFAICS it's all just default UINavigationBar behaviour.

Answer 1

I solved it like this:

override func viewWillDisappear(_ animated: Bool) {
    navigationController?.navigationBar.tintAdjustmentMode = .normal
    navigationController?.navigationBar.tintAdjustmentMode = .automatic
}

so it will restore the color before the other view appear

Answer 2

What I do is work around this bug, in the view controller's viewWillAppear, as follows:

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    self.navigationController?.navigationBar.tintAdjustmentMode = .normal
    self.navigationController?.navigationBar.tintAdjustmentMode = .automatic
}

That seems to wake up the button without visual artifacts.

Answer 3

Another work around is to implement the fix on the parent navigationController - so that each of its child viewController's gets the fix as follows

NOTE: This requires the receiving class to be setup as the UINavigationController delegate

Swift

func navigationController(_ navigationController: UINavigationController, willShow viewController: UIViewController, animated: Bool) {
    if #available(iOS 11.2, *) {
        navigationBar.tintAdjustmentMode = .normal
        navigationBar.tintAdjustmentMode = .automatic
    }
}

Objective-C

-(void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {    
    if (@available(iOS 11.2, *)) {
        self.navigationBar.tintAdjustmentMode = UIViewTintAdjustmentModeNormal;
        self.navigationBar.tintAdjustmentMode = UIViewTintAdjustmentModeAutomatic;
    }
}

Answer 4

This is a bug in iOS 11.2 and happens because the UIBarButtonItem stays highlighted after navigation and does not return to its normal state after the other view controller pops.

To avoid this behavior, either

1. use a UIBarButtonItem with a UIButton as a custom view

2. disable and re-enable the bar button item in viewWillDisappear(_:) (although this causes the button to appear immediately, use matt's solution to avoid this):

   barButtonItem.isEnabled = false
   barButtonItem.isEnabled = true