类型“ AreaData”不符合协议“可编码”

Question

When I make a model for my JSON file, I get these two errors.

1) I got the conform error in AreaData struct

2) " AnyObject cannot be used as a type conforming to protocol Decodable because Decodable has static requirements" error in initialiser.

I have tried several ways but I cannot find the correct solution. How can I make a proper model for this nested/complex JSON?

Here is my JSON file. This data is nested

[
    {
        "ID": "01",
        "Name": "Area 01",
        "parentId": null,
        "sublevel": [
            {
                "ID": "01-01",
                "Name": "Building 01",
                "On": "",
                "Off": "",
                "parentId": "01",
                "sublevel": [
                    {
                        "ID": "01-01-01",
                        "Name": "Flat 01",
                        "On": "",
                        "Off": "",
                        "parentId": "01-01",
                        "sublevel": []
                    }
                ]
            },
            {
                "ID": "01-02",
                "Name": "Building 02",
                "On": "01",
                "Off": "03",
                "parentId": "01",
                "sublevel": [
                    {
                        "ID": "01-02-01",
                        "Name": "Flat 01",
                        "On": "",
                        "Off": "",
                        "parentId": "01-02",
                        "sublevel": []
                    },
                    {
                        "ID": "01-02-02",
                        "Name": "Flat 02",
                        "On": "01",
                        "Off": "02",
                        "parentId": "01-02",
                        "sublevel": []
                    },
                    {
                        "ID": "01-02-03",
                        "Name": "Flat 03",
                        "On": "02",
                        "Off": "12",
                        "parentId": "01-02",
                        "sublevel": [
                            {
                                "ID": "01-02-03-01",
                                "Name": "Room 01",
                                "On": "",
                                "Off": "",
                                "parentId": "01-02-03",
                                "sublevel": []
                            },
                            {
                                "ID": "01-02-03-02",
                                "Name": "Room 02",
                                "On": "",
                                "Off": "",
                                "parentId": "01-02-03",
                                "sublevel": []
                            },
                            {
                                "ID": "01-02-03-03",
                                "Name": "Room 03",
                                "On": "02",
                                "Off": "03",
                                "parentId": "01-02-03",
                                "sublevel": []
                            },
                            {
                                "ID": "01-02-03-04",
                                "Name": "Room 04",
                                "On": "",
                                "Off": "",
                                "parentId": "01-02-03",
                                "sublevel": []
                            },
                            {
                                "ID": "01-02-03-05",
                                "Name": "Room 05",
                                "On": "01",
                                "Off": "",
                                "parentId": "01-02-03",
                                "sublevel": []
                            }
                        ]
                    },
                    {
                        "ID": "01-02-04",
                        "Name": "Flat 04",
                        "On": "12",
                        "Off": "03",
                        "parentId": "01-02",
                        "sublevel": []
                    },
                    {
                        "ID": "01-02-05",
                        "Name": "Flat 05",
                        "On": "02",
                        "Off": "",
                        "parentId": "01-02",
                        "sublevel": []
                    }
                ]
            },
            {
                "ID": "01-03",
                "Name": "Building 03",
                "On": "02",
                "Off": "01",
                "parentId": "01",
                "sublevel": []
            },
            {
                "ID": "01-04",
                "Name": "Building 04",
                "On": "",
                "Off": "",
                "parentId": "01",
                "sublevel": []
            }
        ]
    }
]

And this is my model class

import Foundation
struct AreaData : Codable {

    let iD : String?
    let name : String?
    let parentId : AnyObject?
    let sublevel : [Sublevel]?

    enum CodingKeys: String, CodingKey {
        case iD = "ID"
        case name = "Name"
        case parentId = "parentId"
        case sublevel = "sublevel"
    }

    init(from decoder: Decoder) throws {
        let values = try decoder.container(keyedBy: CodingKeys.self)
        iD = try values.decodeIfPresent(String.self, forKey: .iD)
        name = try values.decodeIfPresent(String.self, forKey: .name)
        parentId = try values.decodeIfPresent(AnyObject.self, forKey: .parentId)
        sublevel = try values.decodeIfPresent([Sublevel].self, forKey: .sublevel)
    }

}

struct Sublevel : Codable {

    let on : String?
    let iD : String?
    let name : String?
    let off : String?
    let parentId : String?
    let sublevel : [Sublevel]?

    enum CodingKeys: String, CodingKey {
        case on = "On"
        case iD = "ID"
        case name = "Name"
        case off = "Off"
        case parentId = "parentId"
        case sublevel = "sublevel"
    }

    init(from decoder: Decoder) throws {
        let values = try decoder.container(keyedBy: CodingKeys.self)
        on = try values.decodeIfPresent(String.self, forKey: .on)
        iD = try values.decodeIfPresent(String.self, forKey: .iD)
        name = try values.decodeIfPresent(String.self, forKey: .name)
        off = try values.decodeIfPresent(String.self, forKey: .off)
        parentId = try values.decodeIfPresent(String.self, forKey: .parentId)
        sublevel = try values.decodeIfPresent([Sublevel].self, forKey: .sublevel)
    }

}

Answer 1

try this,

 struct AreaDataModel: Codable {
    let id, name: String
    let parentID: String? // AnyObject can't conform to Encodable protocol .  
    let sublevel: [Sublevel]

    enum CodingKeys: String, CodingKey {
        case id = "ID"
        case name = "Name"
        case parentID = "parentId"
        case sublevel
    }
}

// MARK: - Sublevel
struct Sublevel: Codable {
    let id, name, on, off: String
    let parentID: String
    let sublevel: [Sublevel]

    enum CodingKeys: String, CodingKey {
        case id = "ID"
        case name = "Name"
        case on = "On"
        case off = "Off"
        case parentID = "parentId"
        case sublevel
    }
}

typealias AreaData = [AreaDataModel]

I recommend this tool simple and fast .

Answer 2

The problem is due to AnyObject . Codabe doesn't support anything like Any or AnyObject . You need to specify the type explicitly.

In the JSON response you added, the parentId is either null or String . So, you can use String? as its type, ie

struct AreaData : Codable {
    let parentId : String? //here.....
    //rest of the code....
}

Also, there is no need to specify the rawValue of the case explitly in enum CodingKeys if the property and the key has an exact match. So the CodingKeys in struct AreaData must be,

enum CodingKeys: String, CodingKey {
    case iD = "ID"
    case name = "Name"
    case parentId, sublevel
}

Moreover, init(from decoder: Decoder) is not required. This is because you're not doing any specific parsing inside it. Direct parsing will be handled by the Codable itself.

So, struct AreaData should look like,

struct AreaData : Codable {
    let iD : String?
    let name : String?
    let parentId : String?
    let sublevel : [Sublevel]?

    enum CodingKeys: String, CodingKey {
        case iD = "ID"
        case name = "Name"
        case parentId, sublevel
    }
}

Make similar changes to struct Sublevel as well.

Also, use Codable only if you want to both encode and decode the data. In case you want a single functionality ie either encode or decode , use Encodable or Decodable instead.

Recommendation:

Since the AreaData and Sublevel contain almost same kind of data, you can use a single struct to decode that JSON , ie

struct AreaData: Decodable {
    let iD : String?
    let name : String?
    let parentId : String?
    let sublevel : [AreaData]?
    let on : String?
    let off : String?

    enum CodingKeys: String, CodingKey {
        case iD = "ID"
        case name = "Name"
        case on = "On"
        case off = "Off"
        case parentId, sublevel
    }
}