在动态类型/对象上使用Codable

时间:2017-10-13 09:13:31

标签: swift swift4 codable

您好我有以下结构嵌套在从api调用返回的更大的结构中,但我无法对此部分进行编码/解码。我遇到的问题是customKey和customValue都是动态的。

{
    "current" : "a value"
    "hash" : "some value"
    "values": {
        "customkey": "customValue",
        "customKey": "customValue"
    }
}

我试过像var values: [String:String]这样的东西但是这显然不起作用,因为它实际上并不是[String:String]的数组。

2 个答案:

答案 0 :(得分:8)

由于您链接到我对另一个问题的回答,我将扩展该问题以回答您的问题。

事实是,如果你知道在哪里看,所有的键在运行时都是已知的:

struct GenericCodingKeys: CodingKey {
    var intValue: Int?
    var stringValue: String

    init?(intValue: Int) { self.intValue = intValue; self.stringValue = "\(intValue)" }
    init?(stringValue: String) { self.stringValue = stringValue }

    static func makeKey(name: String) -> GenericCodingKeys {
        return GenericCodingKeys(stringValue: name)!
    }
}


struct MyModel: Decodable {
    var current: String
    var hash: String
    var values: [String: String]

    private enum CodingKeys: String, CodingKey {
        case current
        case hash
        case values
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        current = try container.decode(String.self, forKey: .current)
        hash = try container.decode(String.self, forKey: .hash)

        values = [String: String]()
        let subContainer = try container.nestedContainer(keyedBy: GenericCodingKeys.self, forKey: .values)
        for key in subContainer.allKeys {
            values[key.stringValue] = try subContainer.decode(String.self, forKey: key)
        }
    }
}

用法:

let jsonData = """
{
    "current": "a value",
    "hash": "a value",
    "values": {
        "key1": "customValue",
        "key2": "customValue"
    }
}
""".data(using: .utf8)!

let model = try JSONDecoder().decode(MyModel.self, from: jsonData)

答案 1 :(得分:0)

简化回答,它正在使用字典[String:String](你可以使用其他结构的字符串的instatead):

let jsonData = """
{
    "current": "a value",
    "hash": "a value",
    "values": {
        "key1": "customValue",
        "key2": "customValue"
    }
}
""".data(using: .utf8)!

struct MyModel: Decodable {
    var current: String
    var hash: String
    var values: [String: String]
}

let model = try JSONDecoder().decode(MyModel.self, from: jsonData)

for (key,value) in model.values {
    print("key: \(key) value: \(value)")
}