iOS 5 [UINavigationBar 外观] setBackgroundImage 不起作用 [英] iOS 5 [UINavigationBar appearance] setBackgroundImage does not do work

问题描述

我在 Xcode 4.2 Build 4D199 中创建了一个新的测试 iOS5 项目，并尝试如上所述设置 UINavigationBar 的外观，但没有任何反应.

I created a new test iOS5 project in Xcode 4.2 Build 4D199 and tried to set the appearance of the UINavigationBar as described above, but nothing happens.

我在viewDidLoad中试过的代码:

[[UINavigationBar appearance] setBackgroundImage:[UIImage imageNamed:@"navbar-iphone.png"] forBarMetrics:UIBarMetricsDefault];

我可以让它工作的唯一方法是在 UINavigationBar 的实例上设置外观.喜欢:

The only way I can get it to work is to set the appearance on the instance of the UINavigationBar. Like:

[self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"navbar-iphone.png"] forBarMetrics:UIBarMetricsDefault];

发生了什么事?有其他人遇到过这个问题吗?

What is going on? Has anyone else had this issue?

推荐答案

viewDidLoad 是搞乱导航控制器导航栏的 appearance 代理的错误位置.在创建导航控制器之前执行此类操作.在您的应用委托的 applicationDidFinishLaunching 中是一个好地方.

viewDidLoad is the wrong place to be messing with the appearance proxy of a navigation controller's navigation bar. Do this sort of thing before the navigation controller is even created. In your app delegate's applicationDidFinishLaunching is a good place.

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