无需重新启动应用程序即可更改 UINavigationBar 背景图像 [英] Changing the UINavigationBar background image without restarting app

问题描述

现在，我有

[[UINavigationBar appearance] setBackgroundImage:[UIImage imageNamed: @"UINavigationBarBackground.png"] 
           forBarMetrics:UIBarMetricsDefault];

我希望它在单击时更改背景.现在，它仅在您重新启动应用程序后才会更改.有没有办法让它改变导航栏的背景图像而不必重新启动应用程序?

I want it to change the background on-click. Right now, it only changes after you restart the app. Is there a way to have it change the background image of the navigation bar without having to restart the app?

我试过了

[[UINavigationBar appearance] setNeedsDisplay];

但它崩溃了:由于未捕获的异常'NSInvalidArgumentException'，终止应用程序，原因:'-[NSMethodSignature getArgumentTypeAtIndex:]: index (2) out of bounds [0, 1]'

but it crashes with: Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSMethodSignature getArgumentTypeAtIndex:]: index (2) out of bounds [0, 1]'

如果我尝试

[self.navigationController.navigationBar setNeedsDisplay];

或

[self.view setNeedsDisplay];

什么都没发生.

推荐答案

UINavigationBar 只是 Apple 在 iOS 中提供的另一个(但有点特殊)子类 UIView，因此您应该能够使用诸如 "setNeedsDisplay" 调整图像后立即.

UINavigationBar is just another (but slightly special) subclassed UIView that Apple provides in iOS, so you should be able to force an update using something like "setNeedsDisplay" right after you adjust the image.

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