Swift Codable 预期解码 Dictionary<String, Any> 但发现 string/data

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"
      }
   ]
}

我只需要关注对象数组，"image-path"数组可以包含0、1或2个字符串。

所以这是我的实现：

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 = ""
    }
}

我以这种方式请求并获取 JSON 数据后，从我的服务 class 调用它：

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

除 image 属性

的 [String] 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 数据场景？

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.删除了init()（我觉得这里没有init()的要求。）

3.在decoder.decode(...)方法

中使用Result.self代替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：

Swift Codable 预期解码 Dictionary<String, Any> 但发现 string/data

Swift Codable expected to decode Dictionary<String, Any>but found a string/data instead

json

swift

swift4

codable