如何在模型中使用 swift 协议 [关闭]

Posted 2023-02-15

【中文标题】如何在模型中使用 swift 协议 [关闭]

【英文标题】：How to work with swift protocols in models [closed]

【发布时间】：2022-01-09 04:12:44

【问题描述】：

JSON：

"sittingFurniture":[

    "sittingObjectType": "chair",
    "fabric": "textile"
,

    "sittingObjectType":"bed",
    "height": 70
,
...
]

Swift 代码：

protocol SittingObject 
    var type: SittingObjectType


public enum SittingObjectType: Codable, Equatable 
    case chair
    case sofa
    case bed


struct FancyChair: SittingObject, Codable, Equatable  
    let fabric: String
    let type: SittingObjectType = .chair


struct FancyBed: SittingObject, Codable, Equatable
    let height: Int
    let type: SittingObjectType = .bed


struct FurnitureList: Codable, Equatable 
    let sittingFurniture: [SittingObject] //ERROR

Protocol 'SittingObject' 只能用作通用约束，因为它具有 Self 或关联的类型要求

我们怎样才能最好地反序列化这样的 JSON？

【问题讨论】：

标题中有一个问题，文本中有另一个问题和一条错误消息。不容易理解你在问什么。

【参考方案1】：

最好像这样设置你的结构，而不是两个单独的对象。

那么你也许可以在FurnitureList上使用JSONDecoder

    struct FancyFurnitureObject: SittingObject, Codable, Equatable  
        let fabric: String?
        let height: Int?
        let type: SittingObjectType
    
    
    public enum SittingObjectType: Codable, Equatable 
        case chair
        case sofa
        case bed
    
    
    struct FurnitureList: Codable, Equatable 
        let sittingFurniture: [FancyFurnitureObject] //ERROR