Updating navigation bar after a change using UIAppearance

问题

I'm currently customising the navigation bar background image of my iOS app using the UIAppearance proxy. There is a button for switching between two different modes which triggers a notification. This notification will change the background to a different image using again the proxy. My problem is that this change becomes visible only when I go to a different controller and I come back to it. I'm not able to force the update of the navigation bar within the controller.

I've tried this in my MainTabBarController:

- (void) onAppChangedMode: (NSNotification*)notif {

APP_MODE mode = (APP_MODE) [[notif object] integerValue];

// change navigation bar appearance
[[UILabel appearance] setHighlightedTextColor:[UIColor redColor]];
[[UINavigationBar appearance] setBackgroundImage:[UIImage imageNamed:(mode == 0 ? @"navbar.png" : @"navbar2.png")] forBarMetrics:UIBarMetricsDefault];
// trying to update
for (UIViewController* vc in self.viewControllers) {
     [vc.navigationController.navigationBar setNeedsDisplay];
}

}

but nothing...it's not working. Any idea how to achieve it?

Thanks!

回答1:

Try this code to change the background image for the current nav bar only:

[self.navigationController.navigationBar setBackgroundImage:image forBarMetrics:UIBarMetricsDefault];

Use the above code after changing the UIAppearance. This will force a change in the nav bar of the current controller. The nav bars for the other controllers will be handled by the change in UIAppearance.

回答2:

Just remove views from windows and add they again:

for (UIWindow *window in [UIApplication sharedApplication].windows) {
    for (UIView *view in window.subviews) {
        [view removeFromSuperview];
        [window addSubview:view];
    }
}

回答3:

I just have the same problem, this code will help you:

- (IBAction)btnTouched:(id)sender {
    [[UADSwitch appearance]setOnTintColor:[UIColor redColor]];

    // Present a temp UIViewController 
    UIViewController *vc = [[UIViewController alloc]init];
    [self presentViewController:vc animated:NO completion:nil];//"self" is an instance of UIViewController
    [vc dismissViewControllerAnimated:NO completion:nil];
}

来源：https://stackoverflow.com/questions/15024037/updating-navigation-bar-after-a-change-using-uiappearance

标签

ios

background

uinavigationbar

updates

uiappearance