参考UIApplication委托 [英] Getting a reference to the UIApplication delegate

问题描述

我正在写我的第一个iPhone应用程序，我无法切换视图。我有2个视图，并且引用了 AppDelegate （一个 UIApplicationDelegate 的实例）。我在 applicationDidFinishLaunching 中创建两个实例，并立即显示第一个视图。这工作正常

问题是另一个视图的引用是在 AppDelegate 中，我无法弄清楚如何引用它我可以切换到另一个视图。有没有办法引用主要的 UIApplication 或 UIApplicationDelegate 对象？

解决方案

是的，UIApplication是一个单例，并使用Objective-C的正常单例模式：

  [UIApplication sharedApplication]; 
  

您可以直接从您的代表类获取：

  MyAppDelegate * delegate =（MyAppDelegate *）[[UIApplication sharedApplication] delegate]; 
  

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 applicationDidFinishLaunching and immediately show the first view. This works fine.

The problem is the reference to the other view is in the AppDelegate and 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 UIApplication or UIApplicationDelegate objects?

解决方案

Yes, UIApplication is a singleton, and uses the normal singleton pattern for Objective-C:

[UIApplication sharedApplication];

You can get your delegate class directly from it:

MyAppDelegate *delegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];

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