SwiftUI导航链接跳转DetailView报错的解决方案咨询

我想让ContentView中的调查列表点击导航链接时打开DetailView，但一直报错：Missing argument for parameter 'newsurvey' in call Insert 'newsurvey: <#Survey#>'

主页ContentView代码 #

struct ContentView: View {
    @State var surveys: [Survey] = []
    @State var isPresented = false
    @State var selectedTab: Int = 0
    @State private var path = [String]()
    let dateFormatter: DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateFormat = "MM/dd/yyyy"
        return formatter
    }()
    
    var body: some View {
        ZStack {
            VStack{
                NavigationView {
                    VStack {
                        Text("")
                            .frame(height: 0)
                            .navigationBarTitleDisplayMode(.inline)
                        //reduces navbartitle height
                            .toolbar {
                                ToolbarItem(placement: .principal) {
                                    Image("RR_Logo_Primary_Full_Color")
                                        .resizable()
                                        .frame(width: 275.0, height: 55.0)
                                        
                                }
                            }
                          
                    
                    List(surveys) { survey in
                        NavigationLink(destination: DetailView(newsurvey: survey)) //must be within navigationview
                        {
                            HStack{
                                ZStack {
                                    Rectangle()
                                        .frame(width: 400, height: 100.0)
                                        .foregroundColor(.white)
                                        
                                        .cornerRadius(4)
                                        
                                    HStack (alignment: .top) {
                                        VStack (alignment: .leading) {
                                            Text(survey.customerName)
                                                .offset(x: -60, y: -2)
                                                .font(.custom("Roboto-Light", size: 24))
                                            
                                            Text(survey.lineName)
                                                .offset(x: -60, y: -5)
                                                .font(.custom("Roboto-Light", size: 18))
                                            
                                            Text("# of conveyors")
                                                .offset(x: -60)
                                        }
                                        VStack {
                                            Text(dateFormatter.string(from: survey.date))
                                                .font(.custom("Roboto-Light", size: 18))
                                                .offset(x: 60)
                                        }
                                        }
                                        
                                    }
                                }
                            }
                    }
                        .listRowInsets(EdgeInsets())
                    }
                }
                .environment(\.defaultMinListHeaderHeight, 1)
                CustomTabBar(surveys: $surveys, isPresented: $isPresented)
                    .frame(height: 60, alignment: .bottom)
                    
            }
        }
    }
}
struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

尝试的DetailView代码（出现"not in scope"错误） #

struct DetailView: View {
    @State var newsurvey: Survey
    @State var surveys: [Survey] = []
    @State private var conveyorName = ""
    @State private var masterTag = ""
    @State private var showAddConveyorSheet = false
    @State private var conveyors: [Conveyor] = []
    
    var body: some View {
        
        NavigationView {
            VStack {
                List {
                    ForEach(conveyors, id: \.name) { conveyor in
                        NavigationLink(destination: ConveyorTrack(conveyor: conveyor)) {
                            Text(conveyor.name)
                        }
                    }
                }
                Button(action: {
                    self.showAddConveyorSheet = true
                }) {
                    Text("Add Conveyor")
                }
            }
            .navigationBarTitle("Conveyors", displayMode: .inline)
            .sheet(isPresented: $showAddConveyorSheet) {
                VStack {
                    HStack {
                        TextField("Conveyor Name", text: $conveyorName)
                        TextField("Master Tag", text: $masterTag)
                            .onTapGesture {
                                // open camera and scan text here
                            }
                    }
                    Button(action: {
                        self.conveyors.append(Conveyor(id: self.conveyorName, name: self.conveyorName, masterTag: self.masterTag))
                        
                        self.conveyorName = ""
                        self.masterTag = ""
                        self.showAddConveyorSheet = false
                    }) {
                        Text("Save")
                    }
                }
            }
        }
    }
}


struct DetailView_Previews: PreviewProvider {
    static var previews: some View {
       DetailView(newsurvey: survey)
    }
}

错误拆解 #

1. 参数传递不匹配：ContentView中调用DetailView(newsurvey: survey)报错，核心原因是DetailView对传入参数的声明不规范，且预览代码中未定义可用的Survey实例。
2. 状态滥用：DetailView中用@State修饰传入的newsurvey是错误的——父视图传入的数据不需要作为可变状态，用常量即可。
3. 预览变量未定义：DetailView_Previews中的survey变量未初始化，导致"not in scope"错误。

修正代码 #

1. 重构DetailView的参数声明

struct DetailView: View {
    // 用常量接收父视图传入的survey，无需@State
    let newsurvey: Survey
    // 仅保留需要本地修改的状态
    @State private var conveyorName = ""
    @State private var masterTag = ""
    @State private var showAddConveyorSheet = false
    @State private var conveyors: [Conveyor] = []
    
    var body: some View {
        NavigationView {
            VStack {
                List {
                    ForEach(conveyors, id: \.name) { conveyor in
                        NavigationLink(destination: ConveyorTrack(conveyor: conveyor)) {
                            Text(conveyor.name)
                        }
                    }
                }
                Button(action: {
                    showAddConveyorSheet = true
                }) {
                    Text("Add Conveyor")
                }
            }
            .navigationBarTitle("Conveyors", displayMode: .inline)
            .sheet(isPresented: $showAddConveyorSheet) {
                VStack {
                    HStack {
                        TextField("Conveyor Name", text: $conveyorName)
                        TextField("Master Tag", text: $masterTag)
                            .onTapGesture {
                                // 扫码逻辑实现
                            }
                    }
                    Button(action: {
                        let newConveyor = Conveyor(id: conveyorName, name: conveyorName, masterTag: masterTag)
                        conveyors.append(newConveyor)
                        
                        conveyorName = ""
                        masterTag = ""
                        showAddConveyorSheet = false
                    }) {
                        Text("Save")
                    }
                }
            }
        }
    }
}

2. 修复预览代码

创建测试用的Survey实例传入预览：

struct DetailView_Previews: PreviewProvider {
    static var previews: some View {
        // 构造测试用Survey实例，补充结构体所需的所有属性
        let testSurvey = Survey(
            customerName: "测试客户",
            lineName: "测试生产线",
            date: Date(),
            conveyors: []
        )
        DetailView(newsurvey: testSurvey)
    }
}

3. 确保数据结构体遵循Identifiable协议

ContentView中的List要求数据源遵循Identifiable，补充协议实现：

struct Survey: Identifiable {
    let id = UUID()
    var customerName: String
    var lineName: String
    var date: Date
    var conveyors: [Conveyor]
    // 补充Survey的其他必要属性
}

struct Conveyor: Identifiable {
    let id: String
    var name: String
    var masterTag: String
    // 补充Conveyor的其他必要属性
}

内容的提问来源于stack exchange，提问作者Isaac Vasquez