Swift – 使用 popViewController 并将数据传递给您要返回的 ViewController [英] Swift – Using popViewController and passing data to the ViewController you're returning to

问题描述

我的第一个视图控制器名为 ViewController 上有一个名为 showSettings 的可选 bool 变量，我正在从 SecondViewController回到ViewController.

I have an optional bool variable called showSettings on my first view controller which is called ViewController, and I'm popping from SecondViewController back to ViewController.

在弹出之前，我想将 bool 设置为 true.由于 ViewController 在内存中，因此实例化另一个视图控制器似乎是错误的.

Before I pop, I want to set the bool to true. Seems wrong to instantiate another view controller since ViewController is in memory.

最好的方法是什么?如果这对您的答案很重要，我没有使用故事板.

What's the best way to do this? I'm not using storyboards, if that's important for your answer.

感谢您的帮助

推荐答案

所以我想通了，主要来自这篇文章 - http://makeapppie.com/2014/09/15/swift-swift-programmatic-navigation-view-controllers-in-swift/

So I figured it out, based mostly from this post – http://makeapppie.com/2014/09/15/swift-swift-programmatic-navigation-view-controllers-in-swift/

在 SecondViewController 中，在类声明上方，添加以下代码:

In SecondViewController, above the class declaration, add this code:

protocol SecondVCDelegate {
    func didFinishSecondVC(controller: SecondViewController)
}

然后在SecondViewContoller里面添加一个类变量:

Then inside of SecondViewContoller add a class variable:

var 委托:MeditationVCDelegate！= 无

然后在按钮所针对的函数内部，添加以下内容:

Then inside of your function that your button targets, add this:

self.navigationController?.popViewControllerAnimated(true)
delegate.didFinishSecondVC(self)

我们在这里所做的是在 SecondViewController 中弹出，并且不传递任何数据，但是由于我们已经定义了一个协议，我们将在 ViewController 中使用它来处理数据.

What we're doing here is doing the pop in SecondViewController, and not passing any data, but since we've defined a protocol, we're going to use that in ViewController to handle the data.

接下来，在 ViewController 中，将您在 SecondViewController 中定义的协议添加到 ViewController 继承自的类列表中:

So next, in ViewController, add the protocol you defined in SecondViewController to the list of classes ViewController inherits from:

class ViewController: UIViewController, SecondVCDelegate { ... your code... }

您需要添加我们在新协议中定义的函数，以使编译器满意.在 ViewController 的类中，添加:

You'll need to add the function we defined in the new protocol in order to make the compiler happy. Inside of ViewController's class, add this:

func didFinishSecondVC(controller: SecondViewController) {
    self.myBoolVar = true
    controller.navigationController?.popViewControllerAnimated(true)
}

在我们调用 didFinishSecondVC 的 SecondViewController 中，我们在 ViewController 类中调用此方法，我们是控制器突然出现.这类似于我们在 SecondViewController 中编写此代码，但我们已将其编写在 ViewController 中，并且我们使用委托来管理两者之间的消息传递.

In SecondViewController where we're calling didFinishSecondVC, we're calling this method inside of the ViewController class, the controller we're popping to. It's similar to if we wrote this code inside of SecondViewController but we've written it inside of ViewController and we're using a delegate to manage the messaging between the two.

最后，在ViewController中，在我们要push到SecondViewController的函数中，添加以下代码:

Finally, in ViewController, in the function we're targeting to push to SecondViewController, add this code:

let secondVC = secondViewController()
secondVC.delegate = self
self.navigationController?.pushViewController(secondVC, animated: true)

就是这样！你应该准备好在两个视图控制器之间传递代码而不使用故事板！

That's it! You should be all set to pass code between two view controllers without using storyboards!

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