从模态呈现的视图控制器导航到根视图控制器

Question

我有以下场景。

根视图控制器 - A

推送视图控制器 - B

呈现的视图控制器 - C

A -> 推 B.

B -> 呈现 C。

我怎样才能从 C 回到 A。

Answer 1

您可以在 C 中编写以下内容

let presenting = self.presentingViewController ?? self.navigationController?.presentingViewController
let navCtrl1 = presenting as? UINavigationController // in case you presented C using b.navigationController.present...
let navCtrl2 = presenting?.navigationController // in case you presented c using b.present...
if let navCtrl = navCtrl1 ?? navCtrl2  {
    self.dismiss(animated: true, completion: {
        navCtrl.popToRootViewController(animated: true)
    })
}

---

更新

我想知道是否有绕过关闭并直接弹出到根视图控制器的方法。我想避免显示视图控制器 B

let presenting = self.presentingViewController ?? self.navigationController?.presentingViewController
let navCtrl1 = presenting as? UINavigationController // in case you presented C using b.navigationController.present...
let navCtrl2 = presenting?.navigationController // in case you presented c using b.present...
if let navCtrl = navCtrl1 ?? navCtrl2  {
    navCtrl.popToRootViewController(animated: false)
    self.dismiss(animated: true, completion: nil)
}

Answer 2

怎么做？

要实现这一点，您必须将呈现控制器 UINavigationController 作为变量传递给您是 present-ing 的视图控制器。让我告诉你怎么做，结果如何。

从vcA 推送到vcB 相当简单。需要注意的一点是，当您从 vcA 推送到 vcB 时，vcA 将在导航堆栈中。考虑到这一点，让我移动一个。

首先对vcC 进行更改，添加一个变量来保存呈现vcC 的视图控制器的UINavigationCongroller，即vcB。执行以下操作（阅读评论）

class ViewControllerC: UIViewController {

    // Variable that holds reference to presenting ViewController's Navigtion controller
    var presentingNavigationController: UINavigationController!

    //Some action that triggers the "Go-back-to-A"
    @objc func pressed() {
        // When the completion block is executed in dismiss,
        // This function will loop through all ViewControllers in the presenting Navigation stack to see if vcA exists
        // Since vcA was earlier pushed to the navigation stack it should exist
        // So we can use the same navigation controller to pop to vcA    
        // Set the animated property to false to make the transition instant
        dismiss(animated: false) {
            self.presentingNavigationController.viewControllers.forEach({
                if let vc = $0 as? ViewController {
                    self.presentingNavigationController.popToViewController(vc, animated: true)
                }
            })
        }
    }

在vcB 中，您可以将以下内容添加到present(_:_:_:) 函数中

// function call
@objc func pressed() {
    let vc = ViewControllerC()
    // Setting the navigation controller for reference in the presented controller
    vc.presentingNavigationController = self.navigationController  
    present(vc, animated: true, completion: nil)
}

结果