SwiftUI MVVM如何迭代并获取数组的索引

Question

我的项目正在创建一个订购应用程序，在这个关于菜单详细信息的屏幕中，有用户可以选择/附加的菜单变体，我需要迭代 [MenuDetailVariantGroup] 数组并且我需要获取索引数组，我该怎么做？在 for 循环中，我还需要将变量附加到 @Published var variantChosen，但是如果我执行 self.viewModel.variantChosen.append(1)，它总是会返回错误。以下是我的代码：

MenuDetailData.swift

struct MenuDetailData: Codable, Identifiable {
    let id = UUID()
    let idMenu: String
    let menuName: String
    let variantGroup: [MenuDetailVariantGroup]
}

MenuDetailVariantGroup.swift

struct MenuDetailVariantGroup: Codable, Identifiable, Hashable {
    let id = UUID()
    let variantGroupName: String
    let variant: [MenuDetailVariant]
    let limit: Int
}

MenuDetailVariant.swift

struct MenuDetailVariant: Codable, Identifiable, Hashable {
    let id = UUID()
    let variantName: String
}

MenuDetailViewModel.swift

class MenuDetailViewModel: ObservableObject, MenuDetailService {
    var apiSession: APIService
    @Published var detaildata: MenuDetailData?
    @Published var variantGroup = [MenuDetailVariantGroup]()
    @Published var variantChosen: Array<Int> = []
    
    var cancellables = Set<AnyCancellable>()
    
    init(apiSession: APIService = APISession()) {
        self.apiSession = apiSession
    }
    
    func getMenuDetail() {
        let cancellable = self.getMenuDetail()
            .sink(receiveCompletion: { result in
                switch result {
                case .failure(let error):
                    print("Handle error: \(error)")
                case .finished:
                    break
                }
                
            }) { (detail) in
                self.detaildata = detail.data
                self.variantGroup = detail.data.variantGroup
        }
        cancellables.insert(cancellable)
    }
    
}

菜单详细视图

struct MenuDetailView: View {
    @ObservedObject var viewModel = MenuDetailViewModel()
    
    var body: some View {
        ForEach(self.viewModel.variantGroup, id: \.self) { vg in
                /*** I Need to get the index of each iteration here, how? ***/
                VStack {
                    HStack {
                        Text(vg.variantGroupName)
                        Text(String(self.viewModel.arrVariantChoosen[0]))
                    }
                    VStack {
                        ForEach(vg.variant, id: \.self) { v in
                            Text(v.variantName)
                        }
                    }
                }
                // I also need to append Int to @Published var variantChosen
                self.viewModel.variantChosen.append(1)
                // This always return error:
                // Type '()' cannot conform to 'View'; only struct/enum/class types can conform to protocols
            }
        }
    }
}

这是我迄今为止尝试过但失败并返回空的代码

// This returns blank
ForEach(0..<self.viewModel.variantGroup.count) { i in
    Text("\(self.viewModel.variantGroup[i].variantGroupName)")
}

// This too returns blank
ForEach(self.viewModel.variantGroup.indices) { i in
    Text("\(self.viewModel.variantGroup[i].variantGroupName)")
}

提前谢谢大家

Answer 1

你可以使用枚举来同时拥有索引和元素，比如

    var body: some View {
        ForEach(Array(self.viewModel.variantGroup.enumerated()), id: \.1) { index, vg in
                /*** I Need to get the index of each iteration here, how? ***/
                VStack {