Hello everyone, I am trying to save data into phone, I got this error.

Type 'Item' does not conform to protocol 'Encodable/Decodable'

Later I googled and modified my code with enumeration, without understanding it. Fortunetly I still get the same error. Can someone explain to me how can I make it work?

import SwiftUI

class ArrayofItems: ObservableObject, Identifiable, Codable {

    var items: [Item] = []

    func addnewItem(itemName: String, itemCount: Int){
        items.append(Item(itemName: itemName, itemCount: itemCount))
    }

}

class Item: ObservableObject, Identifiable, Codable  {

    enum CodingKeys: CodingKey {
        case itemName
        case id
        case itemCount
    }

    required init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        itemName = try container.decode(String.self, forKey: .itemName)
        itemCount = try container.decode(Int.self, forKey: .itemCount)
    }

   @Published var id = UUID()
   @Published var itemName: String
   @Published var itemCount: Int

    init(itemName: String, itemCount: Int) {
        self.itemName = itemName
        self.itemCount = itemCount
    }

    func add() {
        itemCount += 1
    }

    func sub() {
        itemCount -= 1
    }

}

extension Item {
    static var sample: [Item] {
        [
            Item(itemName: "Item1", itemCount: 3),
            Item(itemName: "Item2", itemCount: 1),
            Item(itemName: "Item3", itemCount: 2)
        ]
    }
}

import Foundation

@MainActor

class allofItems: ObservableObject {

    @Published var allItems: [ArrayofItems] = []

    private static func fileURL() throws -> URL {
        try FileManager.default.url(for: .documentDirectory,
                                    in: .userDomainMask,
                                    appropriateFor: nil,
                                    create: false)
        .appendingPathComponent("item.data")
    }

    func load() async throws {
        let item = Task<[ArrayofItems], Error> {
            let fileURL = try Self.fileURL()
            guard let data = try? Data(contentsOf: fileURL) else {
                return []
            }
            let myitems = try JSONDecoder().decode([ArrayofItems].self, from: data)
            return myitems
        }

        let allItems = try await item.value
        self.allItems = allItems
    }

    func save(allItems: [ArrayofItems]) async throws {
            let task = Task {
                let data = try JSONEncoder().encode(allItems)
                let outfile = try Self.fileURL()
                try data.write(to: outfile)
            }
            _ = try await task.value
        }

}

You're getting a "Type 'Item' does not conform to protocol 'Encodable/Decodable'" error because you need to add an encode(to encoder: Encoder) method in your Item class. This method defines how to encode your Item objects for saving or transmission. Add this method to resolve the error.