json - Swift 将 key 添加到本地 JSON 以保存复选标记

Question

我正在尝试在我的应用程序中保存复选标记。但是因为我的数据来自 api.. 我不知道如何添加像“checked”这样的键。问题是 JSON 每周下载一次，添加新内容。有没有办法仍然保存我的复选标记？

struct Base : Codable {
    let expireDate : String
    let Week : [Weeks]
}

struct Weeks : Codable {
    let name : String
    let items : [Items]
}

struct Items : Codable {
    let Icon: String
    let text : String
}

在我的 RootTableView 中，我有数组 Weeks，我想向子 tableView 项目添加复选标记。

提前致谢

更新:

  //
    //      Download JSON
    //
    enum Result<Value> {
        case success(Value)
        case failure(Error)
    }

    func getItems(for userId: Int, completion: ((Result<Base>) -> Void)?) {
        var urlComponents = URLComponents()
        urlComponents.scheme = "https"
        urlComponents.host = "api.jsonbin.io"
        print(NSLocale.preferredLanguages[0])

        let preferredLanguage = NSLocale.preferredLanguages[0]
        if preferredLanguage.starts(with: "de"){
            urlComponents.path = "/b/xyz"
        }
        else
        {
            urlComponents.path = "/xyz"
        }

        let userIdItem = URLQueryItem(name: "userId", value: "\(userId)")
        urlComponents.queryItems = [userIdItem]
        guard let url = urlComponents.url else { fatalError("Could not create URL from components") }

        var request = URLRequest(url: url)
        request.httpMethod = "GET"


        let config = URLSessionConfiguration.default
        config.httpAdditionalHeaders = [
        "secret-key": "xyzzy"
        ]

        let session = URLSession(configuration: config)
        let task = session.dataTask(with: request) { (responseData, response, responseError) in
            DispatchQueue.main.async {
                if let error = responseError {
                    completion?(.failure(error))
                } else if let jsonDataItems = responseData {
                    let decoder = JSONDecoder()

                    do {
                        let items = try decoder.decode(Base.self, from: jsonDataItems)
                        completion?(.success(items))
                    } catch {
                        completion?(.failure(error))
                    }
                } else {
                    let error = NSError(domain: "", code: 0, userInfo: [NSLocalizedDescriptionKey : "Data was not retrieved from request"]) as Error
                    completion?(.failure(error))
                }
            }
        }

        task.resume()
    }


    func loadJson() {
        getItems(for: 1) { (result) in
            switch result {
            case .success(let item):
                self.saveItemsToDisk(items: item)
                self.defaults.set(item.expireDate, forKey: "LastUpdateItems")
            case .failure(let error):
            fatalError("error: \(error.localizedDescription)")
            }
            self.getItemesFromDisk()
        }
    }

    //
    //      Save Json Local
    //

    func getDocumentsURL() -> URL {
        if let url = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first {
            return url
        } else {
            fatalError("Could not retrieve documents directory")
        }
    }

    func saveItemsToDisk(items: Base) {
        // 1. Create a URL for documents-directory/items.json
        let url = getDocumentsURL().appendingPathComponent("items.json")
        // 2. Endcode our [Item] data to JSON Data
        let encoder = JSONEncoder()
        do {
            let data = try encoder.encode(items)
            // 3. Write this data to the url specified in step 1
            try data.write(to: url, options: [])
        } catch {
            fatalError(error.localizedDescription)
        }
    }

    func getItmesFromDisk(){
        // 1. Create a url for documents-directory/items.json
        let url = getDocumentsURL().appendingPathComponent("items.json")
        let decoder = JSONDecoder()
        do {
            // 2. Retrieve the data on the file in this path (if there is any)
            let data = try Data(contentsOf: url)
            // 3. Decode an array of items from this Data
            let items = try decoder.decode(Base.self, from: data)
            itemsDisk = items
        } catch {

        }
    }

Answer 1

我将为 Items 创建一个包装类(或结构)，例如 MyItem，其中包含原始 Items 对象和复选标记属性。

class MyItem {
    let item: Items
    var checkmark: Bool
    //more properties...?

    init(withItem item: Items {
        this.item = item  
        this.checkmark = false
    }

    func isEqual(otherItem item: Items) -> Bool {
        return this.item == item
    }
}

isEqual 用于检查是否已存在下载的 Items 对象的 MyItem 对象，或者是否应创建一个新对象。 isEqual 假设您更改 Items 结构以实现 Equatable 协议(protocol)。

您可能还需要替换 Weeks，但在这里您不需要包含原始 Weeks 对象。

class MyWeek {
    let name: String
    let items: [MyItem]
}