Swift 中的 iOS 私有/公共数据管理和存储

Question

是否可以显示为从网络和相同模型检索但从核心数据检索的一个数组对象。目的是让相同的数据可能是公共的（然后从网络中检索）或私有的，然后这些数据本地存储在 coredata 模型中。两者的属性/属性将相同。

我打算将其显示为 swiftUI 视图（如果重要的话）

经过一番搜索，我想到了一个结构，该结构基于其隐私属性将被转换为核心数据类模型，或者如果公共直接连接到网络层？

例如（一些伪 swift ;)）

struct Note {
   let note: String
   let isPrivate: Bool

   func save(self) {
       if self.isPrivate { save to CoreData }
       else { send save request with use of networking }
   }
}

class coreDataModel: NSManagedObject {
   var note: String
   let isPrivate = true
}

struct networkingModel {
   var note: String
   let isPrivate = false
}

class modelManager {
   func joinData() {
       let joinedModel: Note = coreDataModel + networkingModel 
    // and so on to display that model

   }
}

Answer 1

我想你可以试试这个，首先用现有的本地数据加载 ui。同时，在后台队列中调用您的 api。一旦 api 结果可用，过滤重复项，然后将其保存在本地。然后最后一步是通知ui重新加载。

这个伪代码有点特定于 UIKit，但是在 SwiftUI 中可以应用相同的逻辑。您不需要关闭，您将直接计算您的发布者对象，并且 ui 将根据任何新的发射做出反应。

/// you can have one model for both api and core data 
struct Note: Hashable { let uuid = UUID.init() }

class ModelManager {
    private var _items: Array<Note> = []

    var onChanged: ((Array<Note>) -> Void)? = nil
    // you might also have an init, where you can have a timer running
    func start() {
        loadFromCoreData { [weak self] (items) in
            guard let `self` = self else { return }
            self._items.append(contentsOf: items)
            self.onChanged?(self._items)
            self.loadFromApi()
        }
    }

    private func loadFromCoreData(completion: @escaping (Array<Note>) -> Void) {
        // background queue
        // logic to load from coredata.
        let coreDataResults: Array<Note> = []
        completion(coreDataResults)
    }

    private func loadFromApi() {
        // background queue
        let apiResults: Array<Note> = []
        compute(contents: apiResults)
    }

    private func compute(contents: Array<Note>) {
        let combined = zip(_items, contents).flatMap{[$0.0, $0.1] }
        let newItems = Array(Set(combined)) // set doesn't allow duplicates 
        // save to db

        // insert to new to _items
        _items.append(contentsOf: newItems)
        // sort maybe to place new items on top
        self.onChanged?(self._items)

    }

}



// usage of this object 
    let manager = ModelManager()
    manager.start()
    manager.onChanged = { items in
        // [weak self] remember of retain cycles
        // make sure you are on main queue when reloading

    }