I have set a custom tint color for a UINavigationBar (within a UINavigationController) which, in turn, sets an appropriate matching color for the UIBarButtonItems which are inserted into the UINavigationBar. However, when I select a UIBarButtonItem the button turns into (presumably) the highlighted state and presents a different color, which looks quite a bit out and does not nicely match the tint color. Is there a way to change this highlighted state color to a custom color?
Ideally, I would like to just create a category on UIBarButtonItem which changes the highlighted color for all instances of UIBarButtonItem, as this would avoid the need to explicitly subclass UIBarButtonItems and then change every reference in my app to use the subclass (which will be tricky, as I am using some third-party libraries which just use UIBarButtonItem and I don't want to go messing with their implementation).
Any help would be greatly appreciated.
From what I remember from facing a similar issue, UINavigationBar will just take the tintColor and make it darker for the UIBarButtonItem (unless the style is set to BarStyleBlack, in which case it makes it a dull gray).
To do what you ask, I would create a custom UIButton with background images for the different control states that match your color scheme, then use this UIButton as the view for a custom UIBarButtonItem.
UIButton *customButton = [UIButton buttonWithType:...];
//normal_button.png and selected_button.png need to be created by you
[customButton setBackgroundImage: [UIImage imageNamed:@"normal_button.png"] forState:UIControlStateNormal];
[customButton setBackgroundImage: [UIImage imageNamed:@"selected_button.png"] forState:UIControlStateSelected];
UIBarButtonItem *barButtonItem = [[UIBarButtonItem alloc] initWithCustomView: customButton];
If you want to try and encapsulate this, you could always create a factory or a custom init method on UIBarButtonItem (via a category) and use the above code (with slight modifications).
I am aware that I am not fully addressing your second point on just overriding the control state with a category. I don't know what method to override in UIBarButtonItem to do such a thing, but you may be able to accomplish what you want via method swizzling (http://cocoadev.com/index.pl?MethodSwizzling) once you find out which method you want to exchange.
I should note that I've only ever used swizzling for testing/debugging.
If you're using Interface Builder, drag and drop an UIButton to the navigation's bar right side, and it gets in as a right navigation bar button item. Then, configure different tints for different states of the button, and you're done. Works in Xcode 10 and Swift 4.
来源：https://stackoverflow.com/questions/4012664/uibarbuttonitem-highlighted-color