为什么我的内部 API 结构无法在 SwiftUI 中成功执行？

问：

我是一个菜鸟，我对自己的问题感到困惑。我的理解可能有限，我查找了一些类似的问题，我发现了不同的问题，比如我缺少 init（我不知道 init 是如何工作的）。

所以！我尝试通过JSON使用外部API。你可以在这里找到它（https://www.abgeordnetenwatch.de/api/v2/politicians）。我的代码工作正常，直到我想在我工作的“政治家”结构旁边添加一个内部结构“party”（在我的代码“partei”中）。经过研究，我认为我需要像我的代码一样构建代码结构。我为 id 和 label 使用了不同的名称，以使其通过编码键工作。

我目前遇到这些错误

“58：28 无法推断通用参数'T' ->在调用函数 'decode（_：from：）' （Foundation.JSONDecoder） 时

58：43 无法将类型“模块”的值转换为预期的参数类型“T.Type”

108：88 调用中缺少参数“partei”的参数 ->'init（politician：partei：）'在这里宣布

我的计划是将内部结构 Partei 中的另一个文本添加到我的 PoliticanDetailView 中

        List(viewModel.parteien, id: \.parteiID) { partei in
            Text("Partei: \(partei.namePartei)")

我的整个混乱代码，如果它可能不符合礼仪，我很抱歉

import SwiftUI

struct Partei: Decodable {
    let parteiID: Int
    let namePartei: String

    private enum CodingKeys: String, CodingKey {
        case parteiID = "id"
        case namePartei = "label"
    }
}

struct Politician: Decodable {
    let id: Int
    let firstName: String
    let lastName: String
    let birthYear: Int?
    let beruf: String?
    let geschlecht: String?
    let partei: Partei
    
    enum CodingKeys: String, CodingKey {
        case id
        case firstName = "first_name"
        case lastName = "last_name"
        case birthYear = "year_of_birth"
        case beruf = "occupation"
        case geschlecht = "sex"
        case partei
    }
    
}


struct Politicians: Decodable {
    let data: [Politician]
}

actor PoliticianDataService {
    func fetchPoliticians() async throws -> [Politician] {
        guard let url = URL(string: "https://www.abgeordnetenwatch.de/api/v2/politicians") else { return [] }
        
        let (data, _) = try await URLSession.shared.data(from: url)
        
        let decoder = JSONDecoder()
        let politicians = try decoder.decode(Politicians.self, from: data)
        return politicians.data
    }
}

actor ParteiDataService {
    func fetchParteien() async throws -> [Partei] {
        guard let url = URL(string: "https://www.abgeordnetenwatch.de/api/v2/parties") else { return [] }

        let (data, _) = try await URLSession.shared.data(from: url)
        
        let decoder = JSONDecoder()
        let parteien = try decoder.decode(Parteien.self, from: data)
        return parteien.data
    }
}

@MainActor
class PoliticianListViewModel: ObservableObject {
    @Published var politicians = [Politician]()
    
    private var dataService = PoliticianDataService()
    
    init() {
        // Additional setup could be done here if needed
    }
    
    func fetchPoliticians() {
        Task {
            do {
                let fetchedPoliticians = try await dataService.fetchPoliticians()
                politicians = fetchedPoliticians
            } catch {
                print(error)
            }
        }
    }
}

class PoliticianDetailViewModel: ObservableObject {
    @Published var parteien = [Partei]()

    private var dataService = ParteiDataService()

    func fetchParteien() {
        Task {
            do {
                let fetchedParteien = try await dataService.fetchParteien()
                parteien = fetchedParteien
            } catch {
                print(error)
            }
        }
    }
}

struct ContentView: View {
    @StateObject var viewModel = PoliticianListViewModel()
    
    var body: some View {
        NavigationView {
            List(viewModel.politicians, id: \.id) { politician in
                NavigationLink(destination: PoliticianDetailView(politician: politician)) {
                    Text("\(politician.firstName) \(politician.lastName)")
                }
            }
            .navigationTitle("Politiker in Deutschland")
        }
        .onAppear {
            viewModel.fetchPoliticians()
        }
    }
}

struct PoliticianDetailView: View {
    let politician: Politician
    let partei: Partei
    

    @StateObject private var viewModel = PoliticianDetailViewModel()  // Create a ViewModel

    var body: some View {
        VStack {
            Text("Name: \(politician.firstName) \(politician.lastName)")
            Text("Geburtsjahr \(politician.birthYear ?? 0)")
            Text("Alter: \(calculateAge(birthYear: politician.birthYear ?? 0)) Jahre")
            Text("Beschäftigt als \(politician.beruf ?? "Unbekannt")")
            Text("Geschlecht: \(politician.geschlecht ?? "Unbekannt")")

            List(viewModel.parteien, id: \.parteiID) { partei in
                Text("Partei: \(partei.namePartei)")
            }
            .onAppear {
                viewModel.fetchParteien()
            }
        }
        .navigationTitle("\(politician.firstName) \(politician.lastName)")
    }

    func calculateAge(birthYear: Int) -> Int {
        let currentYear = Calendar.current.component(.year, from: Date())
        return currentYear - birthYear
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}