Swift 基础 Codable(JSONEncoder JSONDecoder)的使用 数据转换成Data传输

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Codable源码地址

前言

Codable的使用一般用于存储模型的数据，模型在存储前通过Codable转换成data，然后取出来之后通过data转换成对应的模型，2.加入使用路由跳转控制器把模型从A控制器传递到B控制器。需要先转换成二进制。传递过去之后把模型还原回来

正题

使用Codable的模型，模型需要遵守Codable协议。

如果模型嵌套模型，每个模型也要遵守Codable协议

举个例子：

import Foundation

enum TimelineMediaType: Int, Codable {
    case unknown
    case images
    case video
}

import Foundation

public enum UserStatus: Int, Codable {
    case none = 0 // 未知
    case free = 1 // 空闲
    case calling = 2 // 在聊
    case resting = 3 // 勿扰
    case hide = 4 // 隐身
    case offline = 6 // 离线
    
    public static func fromInt(_ value: Int) -> UserStatus {
        switch value {
        case 1: return .free
        case 2: return .calling
        case 3: return .resting
        case 4, 5: return .hide
        case 6, 7: return .offline
        default: return .none
        }
    }
    
    public var description: String {
        switch self {
        case .none: return ""
        case .free: return "空闲"
        case .calling: return "在聊"
        case .resting: return "勿扰"
        case .hide: return "隐身"
        case .offline: return "离线"
        }
    }
}

import Foundation

struct GreetingSelectionCache: Codable {
    var textID: Int64 = 0
    var voiceID: Int64 = 0
    var pictureID: Int64 = 0
}

import Foundation

class TimelineDetailModel: Codable {
    var timelineDetailType: TimelineMediaType
    var onlineState: UserStatus
    var title: String
    var cache: GreetingSelectionCache

    init(
       _ timelineDetailType: TimelineMediaType = .unknown,
       _ onlineState: UserStatus = .none,
       _ title: String = "",
       _ cache: GreetingSelectionCache = GreetingSelectionCache(textID: 0, voiceID: 0, pictureID: 0)
    ) {
        self.timelineDetailType = timelineDetailType
        self.onlineState = onlineState
        self.title = title
        self.cache = cache
    }

}

使用：

override func viewDidLoad() {
    super.viewDidLoad()
    view.backgroundColor = .white
    
    let JSONEncoderModel = TimelineDetailModel()
    JSONEncoderModel.timelineDetailType = .images
    JSONEncoderModel.onlineState = .calling
    JSONEncoderModel.title = "fenghanxu"
    let cache = GreetingSelectionCache(textID: 1, voiceID: 2, pictureID: 3)
    JSONEncoderModel.cache = cache
    guard let data = try? JSONEncoder().encode(JSONEncoderModel) else { return }
    
    let JSONDecoderModel = try? JSONDecoder().decode(TimelineDetailModel.self, from: data)
    print("timelineDetailType: \(String(describing: JSONDecoderModel?.timelineDetailType))")
    print("onlineState: \(String(describing: JSONDecoderModel?.onlineState))")
    print("title: \(String(describing: JSONDecoderModel?.title))")
    print("cache: \(String(describing: JSONDecoderModel?.cache))")
    
}

打印结果：

timelineDetailType: Optional(SwiftDemol.TimelineMediaType.images)
onlineState: Optional(SwiftDemol.UserStatus.calling)
title: Optional("fenghanxu")
cache: Optional(SwiftDemol.GreetingSelectionCache(textID: 1, voiceID: 2, pictureID: 3))