如何在iOS 11中将导航栏设置为透明

Question

How to set navigation bar to transparent and get smooth transition from normal to transparent in iOS 11?

before iOS 11, I find the _UIBarBackground view and set it's alpha in viewWillAppear: , and it worked fine when pop, push and swipe back.

But in iOS 11, _UIBarBackground 's alpha will be set to 1 after viewDidAppear automatically.

So I'm wonder, is there any other perfect solutions?

Answer 1

• Set 'Under top bars for view controller' in storyboard, so your view will be under navigation bar

• Add subview to your view with frame {0,0,screenWidth,64}, or use auto layout constraints for it.

• Set background color of that view:

Set background of navbar to transparent:

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    [self.navigationController.navigationBar setBackgroundImage:[UIImage new]
                             forBarMetrics:UIBarMetricsDefault];
    self.navigationController.navigationBar.shadowImage = [UIImage new];
    self.navigationController.navigationBar.translucent = YES;
    self.navigationController.view.backgroundColor = [UIColor clearColor];
    self.navigationController.navigationBar.backgroundColor = [UIColor clearColor];
}

Now you can change yelow view to transparent with animation

Example project: https://github.com/josshad/AnimatedNavBar