如何在Swift中获取容器内的视图？ [英] How do I get the views inside a container in Swift?

问题描述

我有一个容器视图，我弹出了我的故事板。有一个很棒的小箭头代表嵌入到另一个场景的segue。该场景的顶级对象由自定义 UIViewController 控制。我想调用一个在我的自定义类中实现的方法。如果我有权访问容器，我如何获取对内部的引用？

I have a Container View that I popped into my storyboard. There's a wonderful little arrow that represents the embed segue to another scene. That scene's top level object is controlled by a custom UIViewController. I want to call a method that's implemented in my custom class. If I have access to the container, how do I get a reference to what's inside?

推荐答案

您可以使用 prepareForSegue ， UIViewController 中的一个方法，可以访问任何被隐藏的 UIViewController 从您当前的视图控制器，这包括嵌入 segues。

You can use prepareForSegue, a method in UIViewController, to gain access to any UIViewController being segued to from your current view controller, this includes embed segues.

关于 prepareForSegue 的文档：

此方法的默认实现不执行任何操作。当需要将相关数据传递给新视图控制器时，视图控制器会覆盖此方法。 segue对象描述了转换，并包含对segue中涉及的两个视图控制器的引用。

The default implementation of this method does nothing. Your view controller overrides this method when it needs to pass relevant data to the new view controller. The segue object describes the transition and includes references to both view controllers involved in the segue.

在你的问题中你提到需要调用一个自定义视图控制器上的方法。以下是如何执行此操作的示例：

In your question you mentioned needing to call a method on your custom view controller. Here's an example of how you could do that:

1。为嵌入segue提供标识符。您可以在界面生成器中执行此操作，方法是选择您的segue，转到属性编辑器并查看 Storyboard Embed Segue 。

1. Give your embed segue a identifier. You can do this in the Interface Builder by selecting your segue, going to the Attributes Editor and looking under Storyboard Embed Segue.

2。创建类如下的类：

引用保持为 embeddedViewController 所以<可以稍后调用code> myMethod 。它被声明为一个隐式解包的可选项，因为给它一个非零的初始值是没有意义的。

A reference is kept to embeddedViewController so myMethod can be called later. It's declared to be an implicitly unwrapped optional because it doesn't make sense to give it a non-nil initial value.

//  This is your custom view controller contained in `MainViewController`.
class CustomViewController: UIViewController {
    func myMethod() {}
}

class MainViewController: UIViewController {
    private var embeddedViewController: CustomViewController!

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let vc = segue.destination as? CustomViewController,
                    segue.identifier == "EmbedSegue" {
            self.embeddedViewController = vc
        }
    }

    //  Now in other methods you can reference `embeddedViewController`.
    //  For example:
    override func viewDidAppear(animated: Bool) {
        self.embeddedViewController.myMethod()
    }
}

3. 设置 UIViewControllers的类在IB中使用 Identity Inspector 。例如：

3. Set the classes of your UIViewControllers in IB using the Identity Inspector. For example:

现在一切都应该有效。希望有所帮助！

And now everything should work. Hope that helps!

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