Ios 如何在widget today扩展中使用核心数据？

我想在今天的扩展中使用核心数据。 我在下面试过一些方法

创建应用程序组和目标应用程序和今日扩展

创建以下CoreDataStack类

完整代码如下：

final class CoreDataStack {
static let sharedStack = CoreDataStack()
var errorHandler: (Error) -> Void = {_ in }
//#1
lazy var persistentContainer: NSPersistentContainer = {
    let container = NSPersistentContainer(name: "spark")
    container.loadPersistentStores(completionHandler: { [weak self](storeDescription, error) in
        if let error = error {
            NSLog("CoreData error \(error), \(error._userInfo)")
            self?.errorHandler(error)
        }
    })
    return container
}()

//#2
lazy var viewContext: NSManagedObjectContext = {
    return self.persistentContainer.viewContext
}()

//#3
// Optional
lazy var backgroundContext: NSManagedObjectContext = {
    return self.persistentContainer.newBackgroundContext()
}()

//#4
func performForegroundTask(_ block: @escaping (NSManagedObjectContext) -> Void) {
    self.viewContext.perform {
        block(self.viewContext)
    }
}

//#5
func performBackgroundTask(_ block: @escaping (NSManagedObjectContext) -> Void) {
    self.persistentContainer.performBackgroundTask(block)
}



private init() {
    //#1
    NotificationCenter.default.addObserver(self,
                                           selector: #selector(mainContextChanged(notification:)),
                                           name: .NSManagedObjectContextDidSave,
                                           object: self.managedObjectContext)

    NotificationCenter.default.addObserver(self,
                                           selector: #selector(bgContextChanged(notification:)),
                                           name: .NSManagedObjectContextDidSave,
                                           object: self.backgroundManagedObjectContext)
}

deinit {
    NotificationCenter.default.removeObserver(self)
}

//#2
lazy var libraryDirectory: NSURL = {
    let urls = FileManager.default.urls(for: .libraryDirectory, in: .userDomainMask)
    return urls[urls.count-1] as NSURL
}()

//#3
lazy var managedObjectModel: NSManagedObjectModel = {
    let modelURL = Bundle.main.url(forResource: "spark", withExtension: "momd")!
    return NSManagedObjectModel(contentsOf: modelURL)!
}()

//#4
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
    let coordinator = NSPersistentStoreCoordinator(managedObjectModel:
        self.managedObjectModel)
    let url = self.libraryDirectory.appendingPathComponent("spark.sqlite")
    do {
        try coordinator.addPersistentStore(ofType:
            NSSQLiteStoreType,
                                           configurationName: nil,
                                           at: url,
                                           options: [
                                            NSMigratePersistentStoresAutomaticallyOption: true,
                                            NSInferMappingModelAutomaticallyOption: true
            ]
        )
    } catch {
        // Report any error we got.
        NSLog("CoreData error \(error), \(error._userInfo)")
        self.errorHandler(error)
    }
    return coordinator
}()

//#5
lazy var backgroundManagedObjectContext: NSManagedObjectContext = {
    let coordinator = self.persistentStoreCoordinator
    var privateManagedObjectContext = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
    privateManagedObjectContext.persistentStoreCoordinator = coordinator
    return privateManagedObjectContext
}()

//#6
lazy var managedObjectContext: NSManagedObjectContext = {
    let coordinator = self.persistentStoreCoordinator
    var mainManagedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
    mainManagedObjectContext.persistentStoreCoordinator = coordinator
    return mainManagedObjectContext
}()

//#7
@objc func mainContextChanged(notification: NSNotification) {
    backgroundManagedObjectContext.perform { [unowned self] in
        self.backgroundManagedObjectContext.mergeChanges(fromContextDidSave: notification as Notification)
    }
}
@objc func bgContextChanged(notification: NSNotification) {
    managedObjectContext.perform{ [unowned self] in
        self.managedObjectContext.mergeChanges(fromContextDidSave: notification as Notification)
    }
}
}
struct CoreDataServiceConsts {
static let applicationGroupIdentifier = "group.zz.zz.zz"//example
}

final class PersistentContainer: NSPersistentContainer {
    internal override class func defaultDirectoryURL() -> URL {
        var url = super.defaultDirectoryURL()
        if let newURL =
            FileManager.default.containerURL(
                forSecurityApplicationGroupIdentifier: CoreDataServiceConsts.applicationGroupIdentifier) {
            url = newURL
        }
        return url
    }

我可以在今天的扩展中使用核心数据！但是，实体是空的。 我对代码进行了测试，一切正常。没有错误（因为我为测试保存了一些数据，所以我可以完美地工作。） 我真的不知道这个问题。

---

xcode有问题吗？

您不必子类化

NSPersistentContainer

就可以设置自定义存储目录

class CoreDataStack {
    public private(set) var persistentContainer: NSPersistentContainer

    public init(withManagedObjectModelName momdName:String, sqliteStoreName storeName:String, storeBaseUrl baseUrl:URL?) {
        guard let modelURL = Bundle(for: type(of: self)).url(forResource: momdName, withExtension:"momd") else {
            fatalError("Error loading model from bundle")
        }

        guard let mom = NSManagedObjectModel(contentsOf: modelURL) else {
            fatalError("Error initializing mom from: \(modelURL)")
        }

        persistentContainer = NSPersistentContainer(name: momdName, managedObjectModel: mom)

        // If a base URL is given, use it. Else use persistent stores default
        if let baseUrl = baseUrl {
            var storeUrl = baseUrl.appendingPathComponent(momdName)
            storeUrl = storeUrl.appendingPathExtension("sqlite")
            let description = NSPersistentStoreDescription(url: storeUrl)
            persistentContainer.persistentStoreDescriptions = [description]
        }

        persistentContainer.loadPersistentStores() { (storeDescription, error) in
            if let error = error {
                    fatalError("Unresolved error \(error)")
            }
        }
    }

    // MARK: - ... save, get context and others ...

}

使用应用程序组目录实例化它：

guard let groupURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: applicationGroupId) else {
        fatalError("could not get shared app group directory.")
    }

let modelName = "Model"
let storeName = "store"

let myStore = CoreDataStack(withManagedObjectModelName: modelName, sqliteStoreName: storeName, storeBaseUrl: groupURL)

尝试创建一个新的“Cocoa Touch框架”，并将您的xcdatamodeld文件和自定义托管对象类放在那里，以便您可以在应用程序和扩展之间共享它们

然后子类NSPersistentContainer

class SparkPersistentContainer: NSPersistentContainer = {
    override class func defaultDirectoryURL() -> URL {
    return FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "group.com.example.your-app")!

    init() {
        let modelURL = Bundle(for: CustomManagedObject.self).url(forResource: "Spark", withExtension: "momd")!
        let model = NSManagedObjectModel(contentsOf: modelURL)!
        super.init(name: "Spark", managedObjectModel: model)
    }
}

---

您是否将核心数据类包括在这两个目标中？（应用程序和扩展）@Adolfo yup！我可以在xcdatamodeld文件中查看应用程序和扩展。谢谢您的回答！商店的名字是什么？我怎样才能找到它？你把它命名为（常数）。它最终成为实际的sqlite文件名

myStoreName.sqlite

。噢！我懂了。然后我如何把今天的扩展课作为上下文来调用呢？方法完全相同。但是……它不起作用：（无论如何，谢谢你的帮助！