当我使用以下测试测试Core数据时，如果符合期望（如图所示），则会收到错误消息“此NSPersistentStoreCoordinator没有永久存储（未知）。它无法执行保存操作。” 但是，我的打印日志的输出确认该便笺已添加到我的核心数据存储中。
override func setUp() {
super.setUp()
managedObjectModel = NSManagedObjectModel.mergedModel(from: nil)
storeCordinator = NSPersistentStoreCoordinator(managedObjectModel: managedObjectModel)
do {
store = try storeCordinator.addPersistentStore(
ofType: NSInMemoryStoreType, configurationName: nil, at: nil, options: nil)
} catch {
XCTFail("Failed to create a persistent store, \(error)")
}
}
func testCoreDataAddNoteItem() {
let expectation = XCTestExpectation(description: #function)
let managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
managedObjectContext.persistentStoreCoordinator = storeCordinator
let entity = NSEntityDescription.entity(forEntityName: Constants.entityName, in: managedObjectContext)!
let coreDataManager = CoreDataManager(mainObjectContext: managedObjectContext, entity: entity)
let note = Note(entity: entity, insertInto: coreDataManager.getMainManagedObjectContext()!)
note.contents = "Contents"
note.title = "title"
note.createdAt = Date()
note.contents = "contents"
note.emoji = String(describing: 0x1F601)
note.updatedAt = Date()
coreDataManager.getMainManagedObjectContext()!.performAndWait {
coreDataManager.saveContext()
}
coreDataManager.getMainManagedObjectContext()!.performAndWait {
let request = NSFetchRequest<Note>(entityName: Constants.entityName)
request.returnsObjectsAsFaults = false
do {
let result = try managedObjectContext.fetch(request)
for data in result as [NSManagedObject] {
print(data.value(forKey: "title") as! String)
print(data.value(forKey: "title") as! String == "title")
XCTAssertEqual(data.value(forKey: "title") as! String, "title")
expectation.fulfill()
}
} catch {
print("Failed")
}
}
wait(for: [expectation], timeout: 3.0)
}
作为参考，这是我的核心数据堆栈：
public protocol CoreDataManagerProtocol {
func saveContext ()
init()
func getMainManagedObjectContext() -> NSManagedObjectContext?
func getChildManagedObjectContext() -> NSManagedObjectContext?
func saveContext (_ context: NSManagedObjectContext)
}
class CoreDataManager: CoreDataManagerProtocol {
// MARK: Properties
private let modelName: String
// private var entity: NSEntityDescription! = nil
// lazy var managedObjectContext: NSManagedObjectContext = {
// // The alternative to this is to set up our own store
// return (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
// }()
private var managedObjectContext: NSManagedObjectContext! = nil
private(set) lazy var childManagedObjectContext: NSManagedObjectContext = {
// Initialize Managed Object Context
let myChildManagedObjectContext = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
// Configure Managed Object Context
myChildManagedObjectContext.parent = self.managedObjectContext
return myChildManagedObjectContext
}()
// NSPersistentContainer - hides implementation details of how persistent stores are configured
lazy var storeContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: Constants.modelName)
container.loadPersistentStores { (storeDescription, error) in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
}
return container
}()
func getMainManagedObjectContext() -> NSManagedObjectContext? {
return managedObjectContext
}
func getChildManagedObjectContext() -> NSManagedObjectContext? {
return childManagedObjectContext
}
init (mainObjectContext: NSManagedObjectContext, entity: NSEntityDescription) {
self.modelName = Constants.modelName // "EmojiNotes"
managedObjectContext = mainObjectContext
// self.entity = NSEntityDescription.entity(forEntityName: Constants.entityName, in: managedObjectContext)!
// self.entity = entity
}
required init() {
managedObjectContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
self.modelName = Constants.modelName
}
func saveContext (_ context: NSManagedObjectContext) {
// performblock and execute on correct thread
context.perform {
if context.hasChanges {
do {
try context.save()
// inform listeners that we have updated the model
// NotificationCenter.default.post(name: Notification.Name.dataModelDidUpdateNotification, object: self, userInfo: nil)
} catch let error as NSError {
print("Unresolved error \(error), \(error.userInfo)")
}
}
}
}
func saveContext () {
if childManagedObjectContext.hasChanges {
childManagedObjectContext.performAndWait {
do {
try childManagedObjectContext.save()
// inform listeners that we have updated the model
// NotificationCenter.default.post(name: Notification.Name.dataModelDidUpdateNotification, object: self, userInfo: nil)
} catch let error as NSError {
print("Unresolved error \(error), \(error.userInfo)")
}
}
}
print (managedObjectContext.persistentStoreCoordinator?.persistentStores.count)
if managedObjectContext.hasChanges {
managedObjectContext.perform {
do {
try self.managedObjectContext.save()
// inform listeners that we have updated the model
// NotificationCenter.default.post(name: Notification.Name.dataModelDidUpdateNotification, object: self, userInfo: nil)
} catch let error as NSError {
print("Unresolved error \(error), \(error.userInfo)")
}
}
}
}
}
我找到了解决方案：
尝试！ coreDataManager.getChildManagedObjectContext（）?. save（）
如何保存而不会出现错误。
那为什么是解决方案？