SwiftUI:如何使用 NavigationViews 切换到新的导航堆栈

Question

我目前正在使用 SwiftUI Beta 5。我有一个工作流程，涉及浏览一系列 View 。最后一个 View 涉及将数据加载到应用程序中并结束该特定工作流的操作。

下载数据后，用户应该能够启动新的工作流程。我想“忘记”旧的 NavigationView，因为一旦工作流完成，返回导航堆栈就没有用了。相反，我想然后导航到“启动” View ，该 View 有效地成为新导航 View 的根。

如何使用 SwiftUI NavigagationViews 使用导航堆栈中的一个 View 导航到具有不同 NavigationView 的另一个 View (从而成为新导航堆栈的根)？

Answer 1

首先，对不起，我想发表一个简单的评论，但没有足够的声望点:(

我刚刚更新了我的方式回到你的根 stackoverflow.com/a/57513566/7786555

您实际上通过您的评论给了我回到根源的新方法的想法。有一个新的根 View 。如果您强制刷新管理根 View 的结构 View ，那么它会自动执行您想要的操作。下面只是回到根(没有动画)。您可以修改示例以更改根 View (而不是使用相同的 View )以满足您的需要。

struct DetailViewB: View {
    @Environment(\.presentationMode) var presentationMode: Binding<PresentationMode>

    @State var fullDissmiss:Bool = false
    var body: some View {
        SGNavigationChildsView(fullDissmiss: self.fullDissmiss){
            VStack {
                Text("This is Detail View B.")

                Button(action: { self.presentationMode.wrappedValue.dismiss() } )
                { Text("Pop to Detail View A.") }

                Button(action: {
                    self.fullDissmiss = true
                } )
                { Text("Pop two levels to Master View with SGGoToRoot.") }
            }
        }
    }
}

struct DetailViewA: View {
    @Environment(\.presentationMode) var presentationMode: Binding<PresentationMode>

    @State var fullDissmiss:Bool = false
    var body: some View {
        SGNavigationChildsView(fullDissmiss: self.fullDissmiss){
            VStack {
                Text("This is Detail View A.")

                NavigationLink(destination: DetailViewB() )
                { Text("Push to Detail View B.") }

                Button(action: { self.presentationMode.wrappedValue.dismiss() } )
                { Text("Pop one level to Master.") }

                Button(action: { self.fullDissmiss = true } )
                { Text("Pop one level to Master with SGGoToRoot.") }
            }
        }
    }
}

struct MasterView: View {
    var body: some View {
        VStack {
            Text("This is Master View.")
            NavigationLink(destination: DetailViewA() )
            { Text("Push to Detail View A.") }
        }
    }
}

struct ContentView: View {

    var body: some View {
        SGRootNavigationView{
            MasterView()
        }
    }
}
#if DEBUG
struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}
#endif

struct SGRootNavigationView<Content>: View where Content: View {
    let cancellable = NotificationCenter.default.publisher(for: Notification.Name("SGGoToRoot"), object: nil)

    let content: () -> Content

    init(@ViewBuilder content: @escaping () -> Content) {
        self.content = content
    }

    @State var goToRoot:Bool = false

    var body: some View {
        return
            Group{
            if goToRoot == false{
                NavigationView {
                content()
                }
            }else{
                NavigationView {
                content()
                }
            }
            }.onReceive(cancellable, perform: {_ in
                DispatchQueue.main.async {
                    self.goToRoot.toggle()
                }
            })
    }
}

struct SGNavigationChildsView<Content>: View where Content: View {
    let notification = Notification(name: Notification.Name("SGGoToRoot"))

    var fullDissmiss:Bool{
        get{ return false }
        set{ if newValue {self.goToRoot()} }
    }

    let content: () -> Content

    init(fullDissmiss:Bool, @ViewBuilder content: @escaping () -> Content) {
        self.content = content
        self.fullDissmiss = fullDissmiss
    }

    var body: some View {
        return Group{
            content()
        }
    }

    func goToRoot(){
        NotificationCenter.default.post(self.notification)
    }
}