swiftui - SwiftUI Nested NavigationView 导航栏消失

Question

我有一个三个视图，它们是列表。结构 MainMenuView: 视图 { @EnvironmentObject var dataModel: DM

var body: some View {

    return NavigationView{
        List {
            Matchup()
            GameSettings()
            EnteringGame()
        }
    }
}

内部匹配（）

struct Matchup: View {
@EnvironmentObject var dataModel: DM    

var body: some View {
    Section(header: Text("MATCH-UP")
        .fontWeight(.heavy)
        .foregroundColor(Color("TPLightGrey"))
    ) {
        NavigationLink(destination: TrendSingleSelect(
            title: .constant("TEAM"),
            col: .constant(self.dataModel.queryColumnTeam1),
            items: .constant(self.dataModel.team1Values) ,
            selection: self.$dataModel.team1ListValue
        )) {
            HStack {
                Text("TEAM")
                Spacer()
                if dataModel.team1ListValue.count == 0 {
                    Text("IS ANY").foregroundColor(Color("TPLightGrey"))
                } else {
                    Text( self.dataModel.team1ListValue.joined(separator: ", ")).foregroundColor(Color("TPOrange"))
                }
            }
        }


    }
    .listRowBackground(Color("TPDarkGrey"))
    .font(.system(size: 14))
    .navigationBarTitle("", displayMode: .inline)
    .navigationBarHidden(true)
}

}

请注意，我隐藏了 NavBar。当用户选择一行时，我想推入导航。：这是最终视图：

var body: some View {

    return VStack  {

        List {
            ForEach(self.items, id: \.self) { item in
                SingleSelectionRow(title: item, isSelected: self.selection.contains(item)) {

                    if self.selection.contains(item) {
                        self.selection = []
                    }
                    else {
                        self.selection = [item]

                    }
                    self.queryCallback()
                }
                .listRowBackground(Color("TPDarkGrey"))
            }//ForEach
        }//list
            .font(.system(size: 14))
    }

    .navigationBarHidden(false)
    .navigationBarTitle(title)
    .navigationBarItems(trailing:
        Button(action: {
               // Actions
                self.reset()
           }, label: {
            Text("Clear")
            }
        )
    )

}

发生的事情是：当我点击卖出时，我推动了那个部分。但是，当它推入时，我看到了导航栏，然后它就被折叠了。但是，当我点击视图中的任何内容以触发视图重新加载时，它会显示出来。

是什么导致导航栏崩溃？

Answer 1

在 MatchupView 中尝试此代码：

struct Matchup: View {
@EnvironmentObject var dataModel: DM    

var body: some View {
NavigationView {            // attention hear************
    Section(header: Text("MATCH-UP")
        .fontWeight(.heavy)
        .foregroundColor(Color("TPLightGrey"))
    ) {
        NavigationLink(destination: TrendSingleSelect(
            title: .constant("TEAM"),
            col: .constant(self.dataModel.queryColumnTeam1),
            items: .constant(self.dataModel.team1Values) ,
            selection: self.$dataModel.team1ListValue
        )) {
            HStack {
                Text("TEAM")
                Spacer()
                if dataModel.team1ListValue.count == 0 {
                    Text("IS ANY").foregroundColor(Color("TPLightGrey"))
                } else {
                    Text( self.dataModel.team1ListValue.joined(separator: ", ")).foregroundColor(Color("TPOrange"))
                }
            }
        }


    }
    .listRowBackground(Color("TPDarkGrey"))
    .font(.system(size: 14))
}                // attention hear************
    .navigationBarTitle("", displayMode: .inline)
    .navigationBarHidden(true)
}

Answer 2

我无法编译您的项目，所以我假设以下解决方案：

您可以将 navigationBarHidden 绑定到变量，以便您可以在某些条件下更改值。像这样：.navigationBarHidden($onOff)

struct ContentView: View {
    @State var onOff = false
    
    var body: some View {
        
        NavigationView {
            Button("Button") {
                self.onOff.toggle()
            }
            .navigationBarTitle(Text("Events"), displayMode: .inline)
            .navigationBarHidden($onOff.wrappedValue)
        }
        // that means only show one view at a time no matter what device I'm working
        .navigationViewStyle(StackNavigationViewStyle())
    }
}

Answer 3

Arrrgh...这是不必要的：MatchupView 中的 .navigationBarHidden(true)