SwiftUI Nested navigationBar消失

Question

我有三个视图，它们是列表。结构视图:MainMenuView{ @EnvironmentObject对象var dataModel: DM

var body: some View {

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

Inside Matchup()

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theNavBar。当用户按tabs键时，我想推入一个导航。：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")
            }
        )
    )

}

发生的情况是:当我点击sell时，我会按下该部分。然而，当它推入时，我看到了navBar，然后它就崩溃了。但是，当我点击视图中的任何内容来触发视图重新加载时，它就会显示出来。

导航栏崩溃的原因是什么？

Answer 1

在MatchupView中尝试以下代码：

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，因此我假设以下解决方案：

您可以将navigationBarHidden绑定到变量，以便在特定条件下更改该值。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

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