如何退回到导航堆栈上的第一个视图控制器 [英] How to unwind to the first view controller on a navigation stack

问题描述

我在将视图展开到登录屏幕时遇到问题。故事板的结构如下：
故事板结构

I have a problem with unwinding my view to login screen. The storyboard structure is as follow: Storyboard Structure

应用程序的用户流程如下：$ VC $上的
用户登录，在每个选项卡栏项上通过modal segue->进入主选项卡屏，导航控制器上的bar按钮可访问配置文件页面，每个选项卡栏项均具有独立的导航控制器，以保持导航控制器结构的线性。 ->单击个人资料页面按钮后，将以模式方式显示个人资料页面->单击个人资料页面上的注销按钮时，它会触发展开搜索并关闭视图控制器

The user flow for the app is as follow: user login on LoginVC-> goes to main tab bar screen by modal segue-> on each tab bar item, I added right bar button on the navigation controller to access profile page, each tab bar item has independent navigation controller to keep the nav controller structure linear. -> once i click profile page button, profile page is presented modally -> when logout button on profile page is clicked, it triggers unwind segue and dismiss view controller

func logoutUser(){

        //Networking.logoutUser()
        print("It goes to login")
        self.performSegue(withIdentifier: "unwindToLogin", sender: self)
}

展开登录是在LoginVC上实现的最左侧的VC.I在配置文件屏幕上连接了unwind segue，并将其称为 unwindToLogin。
我只使用了performSegueWithIdentifier。但是，该方法不会被调用，并且视图不会发生任何事情。

The unwind segue was implemented on LoginVC on the leftmost VC.I connected unwind segue on the profile screen and call it "unwindToLogin" I simply used performSegueWithIdentifier. However, the method does not get called and nothing happen to the view.

编辑1：
我想知道自从我在选项卡栏vc上以模式方式调用个人资料页面后，找不到unwindtologin。
如果我只是使用InstantiateViewContoller调用登录，是否会清除我的视图控制器堆栈？

Edit 1: Im wondering since i call profile page modally on tab bar vc, it couldnt find the unwindtologin. If i simply use the instantiateviewcontoller to call login, will it clear my view controller stack ?

编辑2：
对不起，我忘了当我检查用户是否登录时，我使用下面的代码：

Edit 2: Sorry, i forgot that when i check if a user is logged in, i use the code below:

    if (FIRAuth.auth()?.currentUser != nil) {
        self.storyboard = UIStoryboard(name: "Main", bundle: Bundle.main)
        self.window?.rootViewController = self.storyboard?.instantiateViewController(withIdentifier: "TabBarViewController")
    }

所以实际上他们找不到展开方法，因为根视图不是主登录视图控制器。

So actually they can't find the unwind method because the root view is not main login view controller.

有人可以帮忙吗？

推荐答案

您需要在要调用的每个ViewController上创建展开序列。他们都可以在登录屏幕中使用相同的 @IBAction 目标，都可以称为 unwindToLogin 。

You need to create the unwind segue on every ViewController that you want to call it on. They can all use the same @IBAction destination in the login screen and they can all be called "unwindToLogin".

我看到在 MainTabBarController 上定义的展开顺序。在您的 UserProfileController 中，您需要 control -从 view Controller 图标拖动到 Exit 图标，然后在弹出窗口中选择您的 @IBAction 。然后在 Document Outline 的 UserProfileController 中找到展开选项，并使其标识符为 unwindToLogin 。

I see the unwind segue defined on the MainTabBarController. In your UserProfileController, you need to control-drag from the view Controller icon to the Exit icon and then select your @IBAction in the pop up. Then find that unwind segue in the UserProfileController in the Document Outline and make its identifier "unwindToLogin".

回应您的 Edit 2：

由于您最初的viewController是通过编程方式放置的，因此无法展开到 LoginViewController 。在这种情况下，
将着陆 @IBAction 放入您的 MainTabBarController 中，并将其设置为 self.window？.rootViewController 进入登录屏幕。

Since your initial viewController was put into place programmatically, it isn't possible to unwind to the LoginViewController. In this case, put the landing @IBAction in your MainTabBarController and have it set the self.window?.rootViewController to the login screen.

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