为什么我的标签栏项目不起作用。 Xcode

Question

因此，当我单击其他两个选项卡栏项目时，它们会起作用，但是，当我单击第三个选项卡时，它会崩溃。我的导航已连接到所有内容

Answer 1

//编辑：如果您想为标签栏项目提供解决方案，我们需要您的TabBar代码，尤其是指示错误所在的地方。似乎您强行打开了一个空的可选内容。

[可能只是和我一样，但在当时的SwiftUI中，使用Tab栏通常很麻烦。我使用的是自定义标签栏，因此只是一个自定义视图，然后将其添加到其他视图的底部，我也可以使用ViewController对其进行控制。

示例：

CustomNavigation.swift：

struct CustomNavigation : View {

@ObservedObject var viewRouter: ViewRouter
let lightGreyColor = Color(red: 102.0/255.0, green: 101.0/255.0, blue: 110.0/255.0, opacity: 0.6)

var body: some View {
    HStack {
        Group {
            Button (action: {
                self.viewRouter.currentView = "home"
            }) {

                HStack(spacing: 15) {
                    Image(systemName: "house")

                    if self.viewRouter.currentView == "home" {
                        Text("Home")
                    }
                }
                .padding(.vertical, 10)
                .padding(.horizontal)
            }
            .foregroundColor(.white)
            .background(Color.blue.opacity(self.viewRouter.currentView == "home" ? 1 : 0))
            .clipShape(RoundedRectangle(cornerRadius: 12))

            Spacer(minLength: 0)

            Button (action: {
                self.viewRouter.currentView = "search"
            }) {

                HStack(spacing: 15) {
                    Image(systemName: "magnifyingglass")

                    if self.viewRouter.currentView == "search" {
                        Text("Search")
                    }
                }
                .padding(.vertical, 10)
                .padding(.horizontal)
            }
            .foregroundColor(.white)
            .background(Color.blue.opacity(self.viewRouter.currentView == "search" ? 1 : 0))
            .clipShape(RoundedRectangle(cornerRadius: 12))

            Spacer(minLength: 0)

            Button (action: {
                self.viewRouter.currentView = "reserved"
            }) {

                HStack(spacing: 15) {
                    Image(systemName: "cart")

                    if self.viewRouter.currentView == "reserved" {
                        Text("Reservierungen")
                    }
                }
                .padding(.vertical, 10)
                .padding(.horizontal)
            }
            .foregroundColor(.white)
            .background(Color.blue.opacity(self.viewRouter.currentView == "reserved" ? 1 : 0))
            .clipShape(RoundedRectangle(cornerRadius: 12))

            Spacer(minLength: 0)

            Button (action: {
                self.viewRouter.currentView = "settings"
            }) {

                HStack(spacing: 15) {
                    Image(systemName: "person")

                    if self.viewRouter.currentView == "settings" {
                        Text("Account")
                    }
                }
                .padding(.vertical, 10)
                .padding(.horizontal)
            }
            .foregroundColor(.white)
            .background(Color.blue.opacity(self.viewRouter.currentView == "settings" ? 1 : 0))
            .clipShape(RoundedRectangle(cornerRadius: 12))
        }

    }
    .padding(.vertical)
    .padding(.horizontal, 25)
    .padding(.bottom, UIApplication.shared.windows.first?.safeAreaInsets.bottom)
    .background(lightGreyColor)
//        .cornerRadius(5)
    .animation(.default)
}
}

ViewRouter.swift：（EnvironmentObject！）

import Foundation
import SwiftUI
import Combine

class ViewRouter: ObservableObject {
    @Published var currentView = "home"
}

实施示例：

struct HomeView: View {
@EnvironmentObject var viewRouter: ViewRouter

var body: some View {
    return Group {
        if self.viewRouter.currentView == "home" {
            HomeFormView()
        } else if self.viewRouter.currentView == "settings" {
            SettingsView()
        }
        else if self.viewRouter.currentView == "search" {
            LoungeList()
        }
        else if self.viewRouter.currentView == "reserved" {
            ReservedView()
        }
        else if self.viewRouter.currentView == "order" {
            OrderView()
        }
        else {
            // .....
        }
    }
}
}

也许这也可以解决您的问题，我一点都没有问题。因为TabBarView对我来说太麻烦了。您必须在SceneDelegate中将ViewRouter设置为environmentObject：

window.rootViewController = UIHostingController(rootView: contentView.environmentObject(ViewRouter()))

希望这会有所帮助！