从 UIViewController 调用 UIViewController 方法深深嵌套在模态中 [英] Call UIViewController method from UIViewController deeply nested in a modal

问题描述

在我的应用程序中，我有一个主"ViewController.在其 viewDidAppear 正文中启动应用程序时，我检索 UserDefaults 布尔值 的值:如果用户未登录，我会以模态呈现另一个 viewcontroller 这样:

In my app I have a "main" ViewController. On app launch in the body of its viewDidAppear, I retrieve the value of a UserDefaults boolean: if the user is not logged in, I present modally another viewcontroller this way:

self.performSegue(withIdentifier:"loginView", sender:self)

这以模态方式启动 AuthViewController，一个包含Container View"的视图控制器，AuthViewController 的一个区域，包含一个 UIPageViewController (AuthPageViewController).

This launches modally AuthViewController, a viewcontroller that contains a "Container View", a region of AuthViewController that includes a UIPageViewController (AuthPageViewController).

最后一个有两个页面":LoginViewController 和 RegisterViewController.

This last one has two "pages": LoginViewController and RegisterViewController.

LoginViewController 用于登录用户:一旦用户登录，我想在主 ViewController 上调用一个函数(无论它做什么).

LoginViewController is used to login users: once the user is logged in I want to call a function (no matter what it does) on the main ViewController.

所以，总而言之，我在 LoginViewController 中，我想调用 ViewController 的方法.

So, to summarize, I’m in LoginViewController and I want to call a method of ViewController.

在尝试解决方案时，我发现了以下内容:

While trying a solution I discovered the following:

• 我无法获得对 presentingViewController 的引用，因为 LoginViewController 尚未直接从 ViewController 中打开.此外，AuthViewController 不是用 present(_:animated:completion:) 启动的，而是用 self.performSegue 启动的，正如我之前所说；
• 从 LoginViewController 实例化一个 ViewController 并调用一个方法是可行的，但这不是一个好主意；
• NSNotification 就像一个魅力；
• 显然代表没有工作，或者我在这个应用程序的比赛中遗漏了他们的实施；

• I can’t get a reference to presentingViewController because LoginViewController has not been opened directly from ViewController. Moreover, AuthViewController was not launched with present(_:animated:completion:) but with self.performSegue as I said before;
• instantiating a ViewController from LoginViewController and calling a method works but it’s not a good idea;
• NSNotification works like a charm;
• apparently delegates aren’t working or I’m missing something about their implementation in the contest of this app;

你能帮我理解如何从我的 LoginViewController 调用 ViewController 方法吗?代码示例很受欢迎，但我很感激任何建议.

Can you help me understand how to call a ViewController method from my LoginViewController? Code examples are very well received, but I appreciate any advice.

推荐答案

我用代码来解释一下这种情况下如何使用delegate，

Let me explain it with code of how to use delegate in this case,

首先你需要像这样在 LoginViewController 中创建一个委托

First you need create a delegate in LoginViewController like this

protocol LoginViewControllerDelegate: class {
    func goToContent(animated:Bool)
}

然后像这样为委托创建一个变量

then create a variable for delegate like this

weak var delegate: LoginViewControllerDelegate?

现在在您的 ViewController 中，您必须在准备 prepareforsegue 方法中像这样分配 delegate，因为您正在使用这样的 segue

Now in you ViewController you have to assign the delegate like this in your prepare prepareforsegue method, as you are using segue like this

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "yourSegueIdentifier" {
        let nextScene =  segue.destination as! LoginViewController
        nextScene.delegate = self
    }
}

并像这样实现该方法

func goToContent(animated: Bool) {
    print("test")
}

通过这种方式，您可以从 LoginViewController

in this way you are able to call goToContent from LoginViewController

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