SwiftUI 中的 TabView 如何取消选择所有选项卡项

Question

是否有可能取消选择选项卡视图中的所有选项卡项。 或者也许我应该以某种方式更改所选项目的颜色以使其看起来没有突出显示

应该发生的情况是 model.selection >= 5

 TabView(selection: $model.selection) {

更新

更多代码：

struct HamburgerTabView: View {

    @EnvironmentObject var model: HamburgerMenuModel

    var body: some View {
        TabView(selection: $model.selection) {
                NavigationView {
                    VStack {
                        Text("Lol").foregroundColor(.black)
                        NavigationLink(destination: Text("NAV").hamburgerButton() ) {
                            Text("Test").foregroundColor(.black)
                        }
                    }
                    .navigationBarTitle("Welcome", displayMode: .inline)
                    .hamburgerButton()


                }
                .tabItem {
                    VStack {
                        Image(systemName: "1.circle")
                        Text("Item 1")
                    }
                }.tag(0)

                NavigationView {
                    Text("Hello World 2").foregroundColor(.red)
                        .navigationBarTitle("Test 2", displayMode: .inline)
                        .hamburgerButton()

                }
                    .tabItem {
                        VStack {
                            Image(systemName: "2.circle")
                            Text("Item 2")
                        }
                    }.tag(1)

                NavigationView {
                    Text("Hello World 3")
                        .navigationBarTitle("Test 3", displayMode: .inline)
                        .hamburgerButton()

                }
                .tabItem {
                        VStack {
                            Image(systemName: "3.circle")
                            Text("Item 3")
                        }
                }.tag(2)

                NavigationView {
                    Text("Hello World 4")
                        .navigationBarTitle("Test 4", displayMode: .inline)
                        .hamburgerButton()

                }
                    .tabItem {
                        VStack {
                            Image(systemName: "4.circle")
                            Text("Item 4")
                        }
                    }.tag(3)

                NavigationView {
                    Text("Hello World 5")
                        .navigationBarTitle("Test 4", displayMode: .inline)
                        .hamburgerButton()

                }
                    .tabItem {
                       VStack {
                            Image(systemName: "5.circle")
                            Text("Item 5")
                        }
                    }.tag(4)
            }
            .onAppear() {
                //UITabBar.appearance().backgroundColor = .red
                //UITabBar.appearance().tintColor = (self.model.selection < 5) ? .green : .red
            }
        .accentColor( (self.model.selection < 5) ? Color.black : Color.black.opacity(0.5))
    }
}

Answer 1

所以我找到了通过扩展来修改它的最简单的解决方案：

extension UITabBarController {
    override open func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        let appearance = UITabBarAppearance()
        appearance.backgroundColor = .white
        appearance.shadowImage = UIImage()
        appearance.shadowColor = .white

        appearance.stackedLayoutAppearance.normal.iconColor = .black
        appearance.stackedLayoutAppearance.normal.titleTextAttributes = [NSAttributedString.Key.foregroundColor: UIColor.black]

        appearance.stackedLayoutAppearance.selected.iconColor = .red
        appearance.stackedLayoutAppearance.selected.titleTextAttributes = [NSAttributedString.Key.foregroundColor: UIColor.red]

        tabBar.standardAppearance = appearance
    }
}

应该有更好的选择，但我只能在视图的构造函数中找到修改一些东西，但它是有限的：

    init() {
        UITabBar.appearance().backgroundColor = UIColor.blue
    }

我希望这有帮助！

编辑

这是我从自定义NavigationView制作的基本自定义TabView ：

struct TabViewItem<E: Comparable, Content>: View where Content: View {

    var id: E
    @Binding var selected: E
    let content: () -> Content

    @inlinable public init(id: E, selected: Binding<E>, @ViewBuilder content: @escaping () -> Content) {
        self.id = id
        self._selected = selected
        self.content = content
    }


    var body: some View {
        HStack {
            Spacer()
            self.content()
            Spacer()
        }
        .padding()
        .background(self.selected == self.id ? Color(UIColor.systemGray5) : Color.clear)
        .contentShape(Rectangle())
        .onTapGesture {
            self.selected = self.id
        }
    }
}

enum Tab : Int, Comparable {
    public static func < (a: Tab, b: Tab) -> Bool {
        return a.rawValue < b.rawValue
    }
    case Home, World, Settings
}



struct ContentView: View {
    @State var selection: Tab = .Home

    func containedView() -> AnyView {
          switch self.selection {
          case .Home: return AnyView(Text("Home"))
          case .World: return AnyView(Text("World"))
          case .Settings: return AnyView(Text("Settings"))
          }
      }

    var body: some View {
        GeometryReader { proxy in
            VStack {
                Spacer()
                self.containedView()
                Spacer()
                HStack(alignment: .bottom, spacing: 0) {
                    TabViewItem(id: Tab.Home, selected: self.$selection, content: {
                        VStack {
                            Image(systemName: "house")
                            Text("Home")
                        }
                    })
                    TabViewItem(id: Tab.World, selected: self.$selection, content: {
                        VStack {
                            Image(systemName: "globe")
                            Text("World")
                        }
                    })
                    TabViewItem(id: Tab.Settings, selected: self.$selection, content: {
                        VStack {
                            Image(systemName: "gear")
                            Text("Settings")
                        }
                    })
                }.frame(width: proxy.size.width, height: 50)
            }
        }
    }
}