SwiftUI:再次点击选定的选项卡时弹出到 Root View

Question

起点是 TabView 中的 NavigationView。当再次点击所选选项卡时，我正在努力寻找一个 SwiftUI 解决方案以弹出到导航堆栈中的 Root View 。在 SwiftUI 之前的时代，这很简单:

func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
    let navController = viewController as! UINavigationController
    navController.popViewController(animated: true)
}

你知道如何在 SwiftUI 中实现同样的功能吗？

目前，我使用以下依赖于 UIKit 的解决方法:

if let windowScene = scene as? UIWindowScene {
            let window = UIWindow(windowScene: windowScene)

            let navigationController = UINavigationController(rootViewController: UIHostingController(rootView:
                MyCustomView() // -> this is a normal SwiftUI file
                    .environment(\.managedObjectContext, context)
            ))
            navigationController.tabBarItem = UITabBarItem(title: "My View 1", image: nil, selectedImage: nil)

            // add more controllers that are part of tab bar controller

            let tabBarController = UITabBarController()
            tabBarController.viewControllers = [navigationController /*,  additional controllers */]

            window.rootViewController = tabBarController // UIHostingController(rootView: contentView)
            self.window = window
            window.makeKeyAndVisible()
        }

Answer 1

这是可能的方法。对于 TabView它提供与点击另一个选项卡并返回相同的行为，因此具有持久的外观和感觉。

经过测试并与 Xcode 11.2/iOS 13.2 一起使用



完整的模块代码:

import SwiftUI

struct TestPopToRootInTab: View {
    @State private var selection = 0
    @State private var resetNavigationID = UUID()

    var body: some View {

        let selectable = Binding(        // << proxy binding to catch tab tap
            get: { self.selection },
            set: { self.selection = $0

                // set new ID to recreate NavigationView, so put it
                // in root state, same as is on change tab and back
                self.resetNavigationID = UUID()
        })

        return TabView(selection: selectable) {
            self.tab1()
                .tabItem {
                    Image(systemName: "1.circle")
                }.tag(0)
            self.tab2()
                .tabItem {
                    Image(systemName: "2.circle")
                }.tag(1)
        }
    }

    private func tab1() -> some View {
        NavigationView {
            NavigationLink(destination: TabChildView()) {
                Text("Tab1 - Initial")
            }
        }.id(self.resetNavigationID) // << making id modifiable
    }

    private func tab2() -> some View {
        Text("Tab2")
    }
}

struct TabChildView: View {
    var number = 1
    var body: some View {
        NavigationLink("Child \(number)",
            destination: TabChildView(number: number + 1))
    }
}

struct TestPopToRootInTab_Previews: PreviewProvider {
    static var previews: some View {
        TestPopToRootInTab()
    }
}