iOS:如何从REST SwiftUi访问和使用接口响应数据

import SwiftUI
import Combine

struct User: Codable {
    let id: Int
    let name: String
    let email: String
}

class NetworkManager {
    func fetchData(completion: @escaping (Result<User, Error>) -> Void) {
        guard let url = URL(string: "https://api.example.com/user") else {
            completion(.failure(NetworkError.invalidURL))
            return
        }
        
        URLSession.shared.dataTaskPublisher(for: url)
            .tryMap { data, response in
                guard let httpResponse = response as? HTTPURLResponse,
                      httpResponse.statusCode == 200 else {
                    throw NetworkError.invalidResponse
                }
                return data
            }
            .decode(type: User.self, decoder: JSONDecoder())
            .receive(on: DispatchQueue.main)
            .sink { completion in
                // 处理请求完成后的操作，例如错误处理
            } receiveValue: { user in
                completion(.success(user))
            }
            .store(in: &cancellables)
    }
    
    enum NetworkError: Error {
        case invalidURL
        case invalidResponse
    }
    
    private var cancellables = Set<AnyCancellable>()
}

struct ContentView: View {
    @State private var user: User?
    private let networkManager = NetworkManager()
    
    var body: some View {
        VStack {
            if let user = user {
                Text("Name: \(user.name)")
                Text("Email: \(user.email)")
            } else {
                Text("Loading...")
            }
        }
        .onAppear {
            networkManager.fetchData { result in
                switch result {
                case .success(let user):
                    self.user = user
                case .failure(let error):
                    // 处理错误
                    print(error)
                }
            }
        }
    }
}