Question

我的应用程序中有一个TabView，用于显示四个屏幕。两者相似，但数据源不同。如果单击第一个选项卡（EventsScreen），然后单击第三个选项卡（MyBagScreen），一切正常。如果我单击第一个选项卡（EventsScreen），然后单击第二个选项卡（EventsScreen），它将仅加载空白屏幕（我假设它仅加载背景）。它们是两个不同的对象，为什么这不起作用？

AppView.swift

struct AppView: View {
    var body: some View {
        TabView {
            EventsScreen().environmentObject(EventsViewModel(repo: IncentivesRespository()))
                .tabItem {
                    Text("Barter")
                    Image("icon_barter")
            }
            EventsScreen().environmentObject(EventsViewModel(repo: OpportunityRepository()))
                .tabItem {
                    Text("Earn")
                    Image("icon_earn")
            }
            MyBagScreen().environmentObject(MyBagViewModel())
                .tabItem{
                    Text("My Bag")
                    Image("icon_bag")
            }
            AccountScreen().environmentObject(AccountViewModel())
                .tabItem {
                    Text("Account")
                    Image("icon_account")

            }
        }
        .onAppear(perform: {
            UITabBar.appearance().backgroundColor = .black
        })
            .navigationBarHidden(true)
    }
}

EventsScreen

struct EventsScreen: View {

    @EnvironmentObject
    var viewModel: EventsViewModel

    let calendarManager = RKManager(calendar: Calendar.current, minimumDate: Date(), maximumDate: Date().addingTimeInterval(60*60*24*90), mode: 1)

    @State
    var currentPage: Int = 0
    @State
    private var searchTerm : String = ""

    init() {
        UITableView.appearance().separatorStyle = .none
    }

    var body: some View {
        GeometryReader { geometry in
            List {
                ZStack(alignment: .top) {
                    EventViewController(controllers: self.viewModel.featureEventControllers, currentPage: self.$currentPage)
                    VStack {
                        SearchBar(text: self.$searchTerm)
                            .padding(EdgeInsets.init(top: 16, leading: 16, bottom: 0, trailing: 16))
                        HStack {
                            Spacer()
                            Chip(text: "Dates", action:  {
                                self.viewModel.showDateSelection.toggle()
                            })
                                .sheet(isPresented: self.$viewModel.showDateSelection, onDismiss: {
                                    self.viewModel.onDatesSelected(startDate: self.calendarManager.startDate, endDate: self.calendarManager.endDate)
                                }, content: {
                                    RKViewController(isPresented: self.$viewModel.showDateSelection, rkManager: self.calendarManager)
                                })
                            Chip(text:"Type", action: {
                                self.viewModel.showTypeSelection.toggle()
                            })
                            Chip(text: "Points", action: {
                                self.viewModel.showPointsSelection.toggle()
                            })
                            Spacer()
                        }
                    }
                }.listRowInsets(EdgeInsets())
                    .frame(height: 600)
                ForEach(self.viewModel.eventSections.indices) { id in
                    EventSectionView(eventSection: self.viewModel.eventSections[id])
                }
                .listRowBackground(Color.black)
            }
            .navigationBarTitle(Text("Events"), displayMode: .inline)
            .navigationBarHidden(true)
            if self.viewModel.showPointsSelection {
                EventsPointsRangeBottomSheet(isOpen: self.$viewModel.showPointsSelection, selectedRange: self.$viewModel.selectedRange, range: 0.0...self.viewModel.maxPoints, action: {
                    self.viewModel.onPointsSelected()
                })

            }
            if self.viewModel.showTypeSelection {
                TypeBottomSheet(categories: self.viewModel.allCategories, isOpen: self.$viewModel.showTypeSelection, selectedCategoryUuids: self.$viewModel.selectedCategoryUuids, action: {
                    self.viewModel.onTypesSelected()
                })
            }

        }
    }
}

Answer 1

您的代码快照不可测试，因此只是一个想法-您必须对其进行测试。

因此，假设您第二个视图的环境对象是正确的，请尝试使用.id修饰符使它们对于视图来说是唯一的，如下所示

TabView {
    EventsScreen().environmentObject(EventsViewModel(repo: IncentivesRespository()))
        .id(1)                    // << here !!
        .tabItem {
            Text("Barter")
            Image("icon_barter")
    }
    EventsScreen().environmentObject(EventsViewModel(repo: OpportunityRepository()))
        .id(2)                    // << here !!
        .tabItem {
            Text("Earn")
            Image("icon_earn")
    }
    ...

注意：：我在.navigationBarHidden(true)中看到用法AppView-如果这意味着您要将TabView包含在NavigationView中，则不要这样做-您将无法使用它。 TabView设计为仅 root视图。如果需要导航，请将其放在标签内。

如果两个视图相同，为什么TabView显示空白屏幕？

1 个答案: