swift - 如何在 Swift 4 中遵循序列协议(protocol)

Question

目前正在尝试快速将 json 字典解析到屏幕上，但是我遇到了这个序列协议(protocol)错误，还有一个类型不匹配错误，它获取一个字符串/数据并期望一个 Int。错误是“类型‘ProductResponse’不符合协议(protocol)‘Sequence’”和

"typeMismatch(Swift.Int, Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "code", intValue: nil)], debugDescription: "Expected to decode Int but found a string/data instead.", underlyingError: nil))"

 struct ProductResponse: Codable {
    let code: String
    let product: Product
    let statusVerbose: String
    let status: Int

    enum CodingKeys: String, CodingKey {
        case code, product
        case statusVerbose = "status_verbose"
        case status
    }
}

struct Product: Codable {
    let code: String
    let productName: String

    enum CodingKeys: String, CodingKey {
        case code
        case productName = "product_name"
    }

}


class ViewController: UIViewController {
    //var products = [Product]()
    let API_URL = "https://carsdata/api/v0/product/5000112630794.json"
    override func viewDidLoad() {
        super.viewDidLoad()
        Alamofire.request(API_URL).responseJSON {
            response in
            let json = response.data
            do
            {
                let decoder = JSONDecoder()
                let productData = try decoder.decode(ProductResponse.self, from: json!)
                for product in productData{  print(product.productName!) } }
            catch
                let err{  print(err) }
        }
    }
}

Answer 1

问题是您没有在 JSON 出现时对其进行解析。你这里有两个对象。 ProductResponse 和 Product 并且您正在尝试将其作为一个解析。 productName 是 Product 的一部分，但您试图从 ProductResponse 获取它。为清楚起见，我建议您创建 2 个实体并尝试这样做:

struct ProductResponse: Codable {
    let code: String
    let product: Product
    let statusVerbose: String
    let status: Int

    enum CodingKeys: String, CodingKey {
        case code, product
        case statusVerbose = "status_verbose"
        case status
    }
}

struct Product: Codable {
    let code: String
    let productName: String

    enum CodingKeys: String, CodingKey {
        case code
        case productName = "product_name"
    }
}

并尝试解码 ProductResponse.self。