objective-c 获取对 UIApplication 委托的引用
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/1184146/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Getting a reference to the UIApplication delegate
提问by derGral
I'm writing my first iPhone application and I'm having trouble switching views. I have 2 views and a reference to each in the AppDelegate(an instance of UIApplicationDelegate). I create instances of both in the applicationDidFinishLaunchingand immediately show the first view. This works fine.
我正在编写我的第一个 iPhone 应用程序，但在切换视图时遇到了问题。我有 2 个视图和对每个视图的引用AppDelegate（一个实例UIApplicationDelegate）。我在 中创建了两者的实例applicationDidFinishLaunching并立即显示第一个视图。这工作正常。
The problem is the reference to the other view is in the AppDelegateand I can't figure out how to get a reference to it so I can switch to the other view. Is there a way to get a reference to the main UIApplicationor UIApplicationDelegateobjects?
问题是对另一个视图的引用在AppDelegate 中，我不知道如何获得对它的引用，以便我可以切换到另一个视图。有没有办法获得对主要UIApplication或UIApplicationDelegate对象的引用？
回答by Louis Gerbarg
Yes, UIApplication is a singleton, and uses the normal singleton pattern for Objective-C:
是的，UIApplication 是一个单例，并且使用 Objective-C 的普通单例模式：
[UIApplication sharedApplication];
You can get your delegate class directly from it:
您可以直接从中获取您的委托类：
MyAppDelegate *delegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];
回答by Codebeef
Use:
用：
[[UIApplication sharedApplication] delegate];
