如何在同一容器中解码 DynamicKeys 和 CodingKeys？

Question

考虑以下JSON：我正在尝试解码"团队"；对象

let jsonString = """
{
"Superheroes":{
"Marvel":"107",
"DC":"106"
},
"teams":{
"106":{
"name":"Marvel",
"Superheroes":{
"890":{
"name":"Batman"
}
}
},
"107":{
"name":"DC",
"Superheroes":{
"891":{
"name":"Wonder Woman"
}
}
}
}
}
"""

我试过这样的东西：

struct SuperheroResponse: Decodable {
let teams: [Team]
private enum CodingKeys: String, CodingKey {
case teams = "teams"
}
private struct DynamicCodingKeys: CodingKey {
var stringValue: String
init?(stringValue: String) {
self.stringValue = stringValue
}
var intValue: Int?
init?(intValue: Int) {
return nil
}
}
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
let teamContainer = try container.nestedContainer(keyedBy: CodingKeys.self, forKey: CodingKeys.teams)
print(teamContainer.allKeys.count)

let tempArray: [Team] = []
for key in teamContainer.allKeys {
let decodedObject = try teamContainer.decode(Team.self, forKey: DynamicCodingKeys(stringValue: key.stringValue)!)
tempArray.append(decodedObject)
}
teams = tempArray
}
}
struct Team: Decodable {
let name: String
}

我想，首先我会得到团队容器，在密钥上绘制地图，然后从那里继续。问题是teamContainer.allKeys.count始终为零。

还有以下行，导致以下错误：无法将"SuperherResponse.DynamicCodingKeys"类型的值转换为预期的参数类型"SuperherResponse.CodingKeys">

let decodedObject = try teamContainer.decode(Team.self, forKey: DynamicCodingKeys(stringValue: key.stringValue)!)

最后我解码如下：

let jsonData = Data(jsonString.utf8)
let decodedResult = try! JSONDecoder().decode(SuperheroResponse.self, from: jsonData)
dump(decodedResult)

如有任何帮助，我们将不胜感激。理想情况下，我想要像SuperherResponse这样的东西->[团队]，团队->name，[超级英雄]，超级英雄->名称

Answer 1

您只是犯了几个小错误。你快到了。

团队容器由DynamicCodingKeys:键控

let teamContainer = try container.nestedContainer(keyedBy: DynamicCodingKeys.self,  // <=
forKey: .teams)

团队可以被解码为使用你得到的密钥：

let decodedObject = try teamContainer.decode(Team.self, forKey: key)

此外，tempArray需要是var:

var tempArray: [Team] = []

或者用map:替换该循环

teams = try teamContainer.allKeys.map {
try teamContainer.decode(Team.self, forKey: $0)
}

总之：

init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
let teamContainer = try container.nestedContainer(keyedBy: DynamicCodingKeys.self, forKey: .teams)
teams = try teamContainer.allKeys.map {
try teamContainer.decode(Team.self, forKey: $0)
}
}