问题描述
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。
解决方法
你可以在C里面写以下内容
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
我想知道是否有任何方法可以绕过关闭并直接弹出到根视图控制器。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)
}
,
怎么样?
要实现这一点,您必须将呈现控制器 UINavigationController
作为变量传递给您正在 present
操作的视图控制器。让我向您展示方法和结果。
从 vcA
推送到 vcB
相当简单。需要注意的一件事是,当您从 vcA
推送到 vcB
时,vcA
将位于导航堆栈中。考虑到这一点,让我移动一个。
首先通过添加一个变量来保存呈现 vcC
的视图控制器的 UINavigationCongroller
,即 vcC
,从而对 vcB
进行更改。请按以下步骤操作(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
// 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)
}