Swift Codable 期望解码 Dictionary<String, Any> 但找到了一个字符串/数据

Question

我一直在使用Codable 协议

这是我的JSON 文件：

    {  
   "Adress":[  

   ],
   "Object":[  
      {  
         "next-date":"2017-10-30T11:00:00Z",
         "text-sample":"Some text",
         "image-path":[  
            "photo1.png",
            "photo2.png"
         ],
         "email":"john.doe@test.com",
         "id":"27"
      },
      {  
         "next-date":"2017-10-30T09:00:00Z",
         "text-sample":"Test Test",
         "image-path":[  
            "image1.png"
         ],
         "email":"name.lastename@doe.com",
         "id":"28"
      }
   ]
}

我只需要关注 Object 数组，“image-path”数组可以包含 0、1 或 2 个字符串。

这是我的实现：

struct Result: Codable {
    let Object: [MyObject]
}

struct MyObject: Codable {

    let date: String
    let text: String
    let image: [String]
    let email: String
    let id: String

    enum CodingKeys: String, CodingKey {
        case date = "next-date"
        case text = "text-sample"
        case image = "image-path"
        case email = "email"
        case id = "id"
    }

    init() {
        self.date = ""
        self.text = ""
        self.image = []
        self.email = ""
        self.id = ""
    }
}

在以这种方式请求和获取 JSON 数据后，我从我的服务类中调用它：

if let data = response.data {
                let decoder = JSONDecoder()
                let result = try! decoder.decode(Result, from: data)
                dump(result.Object)
            }

除了 image 属性的 [String] 之外，一切正常

但它无法编译，或者我收到“Expected to decode...”错误。

我应该如何处理 nil/no data 场景？

Answer 1

我对你的MyObject struct做了一个小改动，即，

1.将所有properties标记为optionals

2.删除init()（我觉得这里没有init()的要求。）

3.在decoder.decode(...)方法中使用Result.self而不是Result

struct MyObject: Codable
{
    let date: String?
    let text: String?
    let image: [String]?
    let email: String?
    let id: String?

    enum CodingKeys: String, CodingKey
    {
        case date = "next-date"
        case text = "text-sample"
        case image = "image-path"
        case email = "email"
        case id = "id"
    }
}

为了测试上面的内容，我使用了下面的代码，它工作正常。

    let jsonString = """
        {"Adress": [],
        "Object": [{"next-date": "2017-10-30T11:00:00Z",
        "text-sample": "Some text",
        "image-path": ["photo1.png", "photo2.png"],
        "email": "john.doe@test.com",
        "id": "27"},
      {"next-date": "2017-10-30T09:00:00Z",
       "text-sample": "Test Test",
       "image-path": ["image1.png"],
       "email": "name.lastename@doe.com",
       "id": "28"}
       ]
        }
    """
    if let data = jsonString.data(using: .utf8)
    {
        let decoder = JSONDecoder()
        let result = try? decoder.decode(Result.self, from: data) //Use Result.self here
        print(result)
    }

这是我得到的结果值：