如何在目标c数据模型类中使用Codable协议? [英] How to use Codable protocol in objective c data model class?

问题描述

我正在研究混合匹配的iOS源代码.我为快速数据模型类实现了可编码，从而减少了编写解析器逻辑的负担.我试图使我的目标c类符合可编码协议，从而引发错误找不到可编码的协议声明".有什么方法可以将此快速协议用于目标c类吗?还是有其他目标c api提供与Codable相同的功能?这样做的目的是使快速和客观c类之间的解析逻辑相同.

I am working on mix and match iOS source code. I have implemented codable for swift data model class which reduces the burden of writing parser logic. I tried to conform my objective c class to codable protcol which in turn thrown an error "Cannot find protocol declaration for 'Codable'". Is there any way to use this swift protocol into objective c class? Or Is there any other objective c api that provides the same capability as Codable? The idea is to make the parsing logic same across swift and objective c classes.

推荐答案

是的，您可以将Codable与Obj-C一起使用.棘手的是，因为Obj-C看不到Decoder，所以当需要从Obj-C端分配它时，您将需要创建一个辅助类方法.

Yes, you can use Codable together with Obj-C. The tricky part is that because Obj-C can't see Decoder, so you will need to create a helper class method when you need it to be allocated from Obj-C side.

public class MyCodableItem: NSObject, Codable {
    private let id: String
    private let label: String?

    enum CodingKeys: String, CodingKey {
        case id
        case label
    }

    @objc public class func create(from url: URL) -> MyCodableItem {
        let decoder = JSONDecoder()
        let item = try! decoder.decode(MyCodableItem.self, from: try! Data(contentsOf: url))
        return item
    }

    public required init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        id = try container.decode(String.self, forKey: .id)
        label = try? container.decode(String.self, forKey: .label)
        super.init()
    }

    required init(coder decoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

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