如何以编程方式创建Unwind segue

问题描述

我不使用情节提要创建应用程序，并且在我的应用程序的这一部分中，我只需要以编程方式创建从ThirdViewController到FirstViewController的展开序列.我知道如何使用sotorybard进行此操作，但找不到如何以编程方式进行操作的任何解决方案.有任何建议吗?

I make an application using no storyboard and in this part of my app I need to create a unwind segue from ThirdViewController to FirstViewController programmatically only. I know how to do it using sotorybard but can't find any solution how to do it programmatically. Any sugestions?

推荐答案

如果没有情节提要，您将无法创建实际的 segue ，但是您可以通过在navigationController.这是连接到按钮以从ThirdViewController返回到FirstViewController的示例:

You can't create an actual segue without a Storyboard, but you can do the equivalent action by calling popToViewController on navigationController. Here is an example that is connected to a button to return to FirstViewController from ThirdViewController:

@IBAction func goBackToFirstVC(sender: UIButton) {
    guard let controllers = navigationController?.viewControllers else { return }
    let count = controllers.count
    if count > 2 {
        // Third from the last is the viewController we want
        if let firstVC = controllers[count - 3] as? FirstViewController {
            // pass back some data
            firstVC.someProperty = someData
            firstVC.someOtherProperty = moreData

            navigationController?.popToViewController(firstVC, animated: true)
        }
    }
}

在viewWillAppear的替代中，您可以对传回的数据进行处理.

In an override of viewWillAppear, you can act upon that data that was passed back.

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