问题描述
我正在使用情节提要开发一个 iOS5 应用程序，并且我在视图控制器类中有一个方法，我想从 App Delegate 访问该方法.问题是，这个视图控制器是通过故事板中的标签栏控制器实例化的，所以 App Delegate 无法直接调用我想要的方法......
I'm working on an iOS5 app using storyboard, and I have a method in a view controller class that i'd like to access from the App Delegate. The trouble is, this view controller gets instantiated via a tab bar controller in storyboard, so the App Delegate has no direct way of calling the method I want...
要让视图控制器与 App Delegate 取得联系，只需使用:
For a view controller to get in touch with the App Delegate, all one has to do is use:
MyAppDelegate *appDelegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];
是否有类似的简单方法可以指向已经实例化的视图控制器或类?
Is there a similarly easy way of pointing to an already-instantiated view controller or class?
推荐答案
您必须从应用委托遍历视图层次结构.假设 AppDelegate 包含对 UITabBarController 的引用，您可以使用 viewControllers 属性或 selectedViewController 属性来获取你的视图控制器.
You'll have to traverse the view hierarchy from the app delegate. Assuming the AppDelegate holds a reference to the UITabBarController, you could use the viewControllers property or selectedViewController property to get to your view controller.
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