SWIFT 5：如何解码嵌套的json数组？

Question

我正在努力使用Swift的Decodable正确解码某些数据。我对此的经验有限，但是在获取一组数据中的嵌套字符串数组时遇到了问题。我尝试从中解码的示例API响应为：

{
  "data": [
    {
      "name": "Arnold",
      "catchphrases": [
        "Ill be back",
        "Hasta la vista baby",
        "Get to the chopper"
      ]
    },
    {
      "name": "Doc Brown",
      "catchphrases": [
        "Great Scott",
        "Where we are going we dont need roads"
      ]
    }
  ]
}

我已经建立了这样的结构：

struct Character: Decodable {
    let name: String
    let catchphrases: [String]
}

struct CharacterCast: Decodable {
    let characters: [Character]
    private enum CodingKeys: String, CodingKey {
        case data = "data"
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        characters = try container.decode([Character].self, forKey: .data)
    }
}

由于某种原因，字符串数组给我带来了问题。我不断收到错误消息：The data couldn’t be read because it is missing.

我不确定是什么问题，但我敢打赌它很简单。我知道我不需要较小结构的编码键，因为属性将直接映射（由于完全匹配）。

Answer 1

不确定您的代码，但至少要避免将结构命名为Data，Character。另外，请注意查看它是对象还是数组。

let json = """
{
  "data": [
    {
      "name": "Arnold",
      "catchphrases": [
        "Ill be back",
        "Hasta la vista baby",
        "Get to the chopper"
      ]
    },
    {
      "name": "Doc Brown",
      "catchphrases": [
        "Great Scott",
        "Where we are going we dont need roads"
      ]
    }
  ]
}
"""

struct MyStruct: Codable {
    let data: [Datum]
}

struct Datum: Codable {
    let name: String
    let catchphrases: [String]
}

let data = json.data(using: .utf8)!

do {
    let d = try JSONDecoder().decode(MyStruct.self, from: data)
    print(d)
} catch {
    print(error)
}