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swift - 按钮操作块内的 Foreach 循环抛出“Type() 不能符合视图”

问题描述

我有一组视图，我需要从中获取值才能将它们保存到我的上下文中。当单击按钮时尝试遍历这些时，我得到“类型'（）'不能符合'视图'；只有结构/枚举/类类型可以符合协议”异常。我对 swift 很陌生，我想知道是否有更简单的方法可以做到这一点。提前谢谢你！

这是完整的视图：

struct DetailedView: View {
    
    @Environment(\.managedObjectContext) var moc
    
    var targetMuscle : String = "Chest"
    let today = Date()
    @State public var exerciseCards : [ExerciseCard] = []
    @State public var exercise : String = "Bench Press"
    @State public var exercises : Int = 0
    @State public var showPassedWorkouts : Bool = false
    
    static let taskDateFormat : DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateStyle = .long
        return formatter
    }()
    
    var body: some View {
        ZStack{
            VStack{
                HStack{
                    VStack{
                        Text(targetMuscle).font(.system(size:40)).fontWeight(.medium)
                        Text("\(today, formatter: Self.taskDateFormat)")
                            .font(.system(size:20))
                    }.frame(width: 250, height: 30, alignment: .topLeading)
                        .navigationBarTitle("")
                        .navigationBarHidden(true)
                        .padding(.bottom, -7)
                    Button(action: {
                        self.showPassedWorkouts.toggle()
                    }) {
                        Text("Passed Workouts")
                            .multilineTextAlignment(.center)
                        
                        
                    }.offset(x: -75, y: 25)
                        .sheet(isPresented: $showPassedWorkouts){
                            PassedWorkoutList()
                    }
                    
                    
                    Button(action: {
                        let workout = Workout(context: self.moc)
                        workout.muscle = self.targetMuscle
                        workout.date = formattedDateString(day: self.today)
                        
                        ForEach(0..<exerciseCards.count, id: \.self){number in
                            let exercise = Exercise(context: self.moc)
                            ForEach(0..<self.exerciseCards[number].tableRows.count, id: \.self){innerNum in
                                let exerciseSet = ExerciseSet(context: self.moc)
                                exerciseSet.reps = self.exerciseCards[number].tableRows[innerNum].reps
                                exerciseSet.weight = self.exerciseCards[number].tableRows[innerNum].weight
                                exerciseSet.set = self.exerciseCards[number].tableRows[innerNum].set
                                exercise.addToExerciseSet(exerciseSet)
                            }
                            workout.addToExercise(exercise)
                        }
                        
                        try? self.moc.save()
                        
                    }) {
                        Text("Finish")
                    }.offset(x: -20, y: 20)
                }.padding(.bottom, 35)
                    .padding(.leading)
                
                
                
                ScrollView{
                    ForEach(0..<exerciseCards.count, id: \.self){ number in
                        self.exerciseCards[number]
                    }
                    
                    
                    Button(action: {
                        self.exerciseCards.append(ExerciseCard())
                    }) {
                        Text("Add Exercise")
                            .frame(minWidth: 325)
                            .padding()
                            .foregroundColor(.white)
                            .background(Color.blue.opacity(0.7))
                            .cornerRadius(20)
                        
                    }.padding(.top)
                        .frame(width: 400)
                }
                
                
            }
        }.background(Color.white)
            
    }
    
}

func formattedDateString(format: String? = "MMM d, h:mm", day: Date) -> String {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = format
    return dateFormatter.string(from: day)
}

上面的视图还引用了两个视图，第一个是练习卡视图

struct ExerciseCard: View {
    @State public var exercise : String = "Bench Press"
    @State public var tableRows : [ExerciseTableRow] = []
    
    var body: some View {
        VStack{
            TextField("Enter Exercise", text: $exercise).textFieldStyle(RoundedBorderTextFieldStyle())
            .frame(width: 300)
            .multilineTextAlignment(.center)
            HStack{
                Group{
                    Text("Set")
                    Text("Weight")
                    Text("Reps")
                }.padding(.horizontal, 30)
                .offset(x: -20, y: 0)
                
            }
            VStack{
                
                ForEach(0..<tableRows.count, id: \.self){ number in
                    self.tableRows[number]
                    
                    
                }
            }.padding(.bottom, 5)
            
            HStack{
                Button(action: {
                    if self.tableRows.count > 1{
                        self.tableRows.remove(at: self.tableRows.count-1)
                    }
                        
                }) {
                    Text("Remove Set")
                        .frame(minWidth: 150)
                        .padding(.vertical, 5)
                        .foregroundColor(.white)
                        .background(Color.red)
                        .cornerRadius(20)
                    
                }
                
                Button(action: {
                    self.tableRows.append(ExerciseTableRow(set: 2, readOnly: false, setWeight: 2, setReps: 2))
                }) {
                    Text("Add Set")
                        .frame(minWidth: 150)
                        .padding(.vertical, 5)
                        .foregroundColor(.white)
                        .background(Color.green)
                        .cornerRadius(20)
                    
                }
                
            }
        }
        .padding()
        .padding(.vertical)
        .background(Color.offWhite)
        .cornerRadius(20)
        .shadow(color: Color.black.opacity(0.2), radius: 10, x:10, y:10)
        .shadow(color: Color.white.opacity(0.7), radius: 10, x:-5, y:-5)
    }
}

第二个是 ExerciseTableRow 视图

struct ExerciseTableRow: View {
    @State public var weight : String = "0"
    @State public var reps : String = "0"
    var set : Int16
    var readOnly : Bool
    var setWeight : Int16
    var setReps : Int16
    var body: some View {
        
        HStack{
            Text(String(set))
                .padding(.trailing, 40)
                .padding(.leading, 10)
            if readOnly == false{
                Group{
                    TextField("0", text: $weight)
                    TextField("0", text: $reps)
                }.textFieldStyle(RoundedBorderTextFieldStyle())
                    .frame(width: 50)
                    .multilineTextAlignment(.center)
                    .keyboardType(.numberPad)
                    .padding(.horizontal, 30)
            }
            else{
                Group{
                    Text(String(setWeight))
                    Text(String(setReps))
                }
                .frame(width: 50)
                    .overlay(
                        RoundedRectangle(cornerRadius: 5)
                            .stroke(Color.black, lineWidth: 1)
                    )
                    .padding(.bottom, 5)
                    .padding(.horizontal, 30)
            }
            
        }
        
        
    }
}

标签： swiftswiftui

解决方案

是ForEach一个 SwiftUI 动态视图容器，用于循环构建视图。对于操作，您必须使用正则 swiftfor .. in表达式，例如

Button(action: {
    let workout = Workout(context: self.moc)
    workout.muscle = self.targetMuscle
    workout.date = formattedDateString(day: self.today)

    for number in 0..<exerciseCards.count {
        let exercise = Exercise(context: self.moc)
        for innerNum in 0..<self.exerciseCards[number].tableRows.count {
            let exerciseSet = ExerciseSet(context: self.moc)
            exerciseSet.reps = self.exerciseCards[number].tableRows[innerNum].reps
            exerciseSet.weight = self.exerciseCards[number].tableRows[innerNum].weight
            exerciseSet.set = self.exerciseCards[number].tableRows[innerNum].set
            exercise.addToExerciseSet(exerciseSet)
        }
        workout.addToExercise(exercise)
    }

    try? self.moc.save()

}) {
    Text("Finish")
}.offset(x: -20, y: 20)

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