获取对 UIApplication 委托的引用

问题描述

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.我在 AppDelegate(UIApplicationDelegate 的一个实例)中有 2 个视图和对每个视图的引用.我在 applicationDidFinishLaunching 中创建了这两个实例并立即显示第一个视图.这工作正常.

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.

问题是对另一个视图的引用在 AppDelegate 中，我不知道如何获取对它的引用，因此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?

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?

推荐答案

是的，UIApplication 是一个单例，并且使用了 Objective-C 的普通单例模式:

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

[UIApplication sharedApplication];

您可以直接从中获取您的委托类:

You can get your delegate class directly from it:

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

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