iOS UINavigationBar button remains faded after segue back

问题

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.

回答1:

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

use a UIBarButtonItem with a UIButton as a custom view
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
```

回答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.

回答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;
    }
}

回答4:

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

来源：https://stackoverflow.com/questions/47754472/ios-uinavigationbar-button-remains-faded-after-segue-back

标签

ios

swift

uinavigationbar

ios11.2