UINavigationBar:appearance works but not UINavigationBar:appearanceWhenContained in

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失恋的感觉
失恋的感觉 2021-02-06 13:00

I have a requirement to set the navigation bar to a custom color and this following code will do that:

[[UINavigationBar appearance]
            setBackgroundIma         


        
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  •  南方客
    南方客 (楼主)
    2021-02-06 13:28

    The argument to appearanceWhenContainedIn: represents a view (and/or view controller) containment hierarchy, not a list of possible containers. (Admittedly, the docs aren't clear on this. See the video from WWDC 2011.) Thus,

    [UINavigationBar appearanceWhenContainedIn:[NSArray arrayWithObjects:[MyViewControllerBase class], [MyViewController1 class], [MyViewController2 class], nil]]
    

    gives you an appearance proxy for a UINavigationBar contained within a MyViewControllerBase, which in turn is within a MyViewController1 inside a MyViewController2. I'm guessing that's not the containment hierarchy you have.

    Instead, look at the view controller which contains your navigation bar. It's probably a generic UINavigationController... but you can't just do

    [UINavigationBar apperanceWhenContainedIn:[NSArray arrayWithObject:[UINavigationController class]]]
    

    because then you'll get the mail/message controllers too. And sadly, while you can get at the appearance proxy for a UINavigationBar within a mail/message view controller, there isn't a way to tell it to undo appearance changes made at a more generic level.

    It looks like the usual solution to such scenarios is to make yourself a UINavigationController subclass, and use it for the parts of your UI you want skinned. The subclass can be empty -- it only exists to identify parts of your UI for appearanceWhenContainedIn:. (Meanwhile, things like MFMailComposeViewController continue to use the default appearance because they still use the generic UINavigationController.)

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