解码具有不同类型的Json对象

Question

I have a Json data which I use to populate Table Views. Json has one two type of object in its main part which are "Main" and n-number tableview object;

Main object has two string type in it ("url" and "bar_name"). Tableview objects has 3 type in it ("name", "id", [tableData]). This is common for all tableview objects (n number). Tabledata object which populate cells has 3 different type because one opens a url, other one opens a new table and last one just do an action.

I want to decode this type of json to structures. Is it possible?

    //For All Types
protocol commonCellTypes: Codable{
    var type: Int { get }

}
struct User: Codable{
    let mainPage: MainPage?
    let tables: [table]?
}
struct MainPage: Codable{
    let url: String?
    let bar_name: String?
}
struct table: Codable{
    let name: String?
    let id: String?
    let Cells: [commonCellTypes]

    enum CodeKeys: CodingKey
    {
        case name
        case id
        case tableDatas
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodeKeys.self)
        name = try container.decode (String.self, forKey: .name)
        id = try container.decode (String.self, forKey: .id)
        Cells = try container.decode ([commonCellTypes].self, forKey: .tableDatas)
    }

    func encode(to encoder: Encoder) throws
    {
        var container = encoder.container(keyedBy: CodeKeys.self)
        try container.encode (name, forKey: .name)
        try container.encode (id, forKey: .id)
        try container.encode (Cells, forKey: .tableDatas)
    }
}
//Type 2
struct cellType2: commonCellTypes{
    let cellText: String
    let imageName: String?
    let url: URL?
    let type: Int
}
//Type 1
struct cellType1: commonCellTypes{
    let cellText: String
    let imageName: String
    let table_id: String
    let type: Int
}
//Type 0
struct cellType0: commonCellTypes{
    let cellText: String
    let imageName: String
    let type: Int
    let action: String
}

EDIT: I found a similar post but doesn't work for my situation. I'm getting below error

Type ' table' does not conform to protocol 'Encodable'

Swift JSONDecoder with multiple structures

EDIT2: I added code for decoding but I'm getting nil for both mainPage and User. What am I missing with my structure?

  let data = try Data(contentsOf: URL(fileURLWithPath: path), options: .alwaysMapped)
            let decoder = JSONDecoder()
            let admin = try! decoder.decode(User.self, from: data)
            print(admin)

Answer 1

You should implement custom initializer for Decoding and encode(to encoder: Encoder) for Encoding. Try this one:

//For All Types
protocol commonCellTypes: Codable{

}
struct MainStruct: Codable{
    let tables: [table]
}
struct table: Codable{
    let name: String?
    let id: String?
    let tableDatas: [commonCellTypes]

    enum CodeKeys: CodingKey
    {
    case name
    case id
    case tableDatas
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodeKeys.self)
        name = try container.decode (String.self, forKey: .name)
        id = try container.decode (String.self, forKey: .id)
        tableDatas = try container.decode ([commonCellTypes].self, forKey: .tableDatas)
    }

    func encode(to encoder: Encoder) throws
    {
        var container = encoder.container(keyedBy: CodeKeys.self)
        try container.encode (name, forKey: .name)
        try container.encode (id, forKey: .id)
        try container.encode (tableDatas, forKey: .tableDatas)
    }
}
//Type 2
struct cellType2: commonCellTypes{
    let cellText: String
    let imageName: String?
    let url: URL?
    let type: Int
}
//Type 1
struct cellType1: commonCellTypes{
    let cellText: String
    let imageName: String
    let table_id: String
    let type: Int
}
//Type 0
struct cellType0: commonCellTypes{
    let cellText: String
    let imageName: String
    let type: Int
    let action: String
}