Ios Swift中具有子类的可解码

我是swift中可解码的新手。我刚刚学会了如何使用它，但我一直在尝试解码另一个类的init中的子类（来自decoder:）

问题是如何从原始类init解码另一个类

我得到一个用户JSON文件，如下所示

{
     firstName:Tim,
     LastName: Apple,
     ...
     socialNetworks: [
         {
             name: Facebook,
             username: Tim85,
             ...
         },
         {
             name: Twitter,
             username: Tim_85,
             ...
         },
         ...
     ],
 }

我有一个像这样的用户类

class User: Codable {

   firstName: String,
   lastName: String,
   ...
   socialNetworks: [SocialNetwork]


   enum CodingKeys: String, CodingKey {
       case firstName, lastName, ..., socialNetworks
   }

   required init(from decoder: Decoder) throws {
       let container = try decoder.container(keyedBy: CodingKeys.self)

       self.firstName = try container.decodeIfPresent(String.self, forKey: .firstName) ?? ""
       self.lastName = try container.decodeIfPresent(String.self, forKey: .lastName) ?? ""

       // How do I also decode SocialNetworks???

   }

   ...

}

我还有一门社交网络课

class SocialNetwork: Codable {

   name: String,
   username: String,
   ...


   enum CodingKeys: String, CodingKey {
       case name, username, ...
   }

   required init(from decoder: Decoder) throws {
       let container = try decoder.container(keyedBy: CodingKeys.self)

       self.name = try container.decodeIfPresent(String.self, forKey: .name) ?? ""
       self.username = try container.decodeIfPresent(String.self, forKey: .userName) ?? ""
   }

   ...

}

---

您不必编写任何自定义init

struct Root: Codable {
    let firstName, lastName: String
    let socialNetworks: [SocialNetwork]

    enum CodingKeys: String, CodingKey { // you can remove this block if LastName starts with l small instead of L
        case firstName
        case lastName = "LastName"
        case socialNetworks
    }
}

struct SocialNetwork: Codable {
    let name, username: String
}

---

试一试吧

self.socialNetworks = try container.decodeIfPresent([SocialNetwork].self, forKey: .socialNetworks) ?? []

---

但是解码器为您执行此操作

首先，它不是一个子类，其次，在我看来，您根本不需要实现

init（from:decoder）

，而是让swift自动为您处理此操作。您应该执行类似于

let result=try decoder.decode（User.self，from:data）

的操作，它应该可以工作。