Swift - コアデータをココアで使用する

Question

OS XアプリケーションではCore Dataと遊んでいます。言語はSwiftです。 Cocoaの仕組みについては奇妙なことがあります。以下は、Xcodeが作成するものの短いバージョンです。

class AppDelegate: NSObject, NSApplicationDelegate { 
    func applicationDidFinishLaunching(aNotification: NSNotification) { 
     // Insert code here to initialize your application 
    } 

    func applicationWillTerminate(aNotification: NSNotification) { 
     // Insert code here to tear down your application 
    } 

    // MARK: - Core Data stack 
    lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = { 
     // The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it. (The directory for the store is created, if necessary.) This property is optional since there are legitimate error conditions that could cause the creation of the store to fail. 
     let fileManager = NSFileManager.defaultManager() 
     var failError: NSError? = nil 
     var shouldFail = false 
     var failureReason = "There was an error creating or loading the application's saved data." 

     // Make sure the application files directory is there 
     do { 
      let properties = try self.applicationDocumentsDirectory.resourceValuesForKeys([NSURLIsDirectoryKey]) 
      if !properties[NSURLIsDirectoryKey]!.boolValue { 
       failureReason = "Expected a folder to store application data, found a file \(self.applicationDocumentsDirectory.path)." 
       shouldFail = true 
      } 
     } catch { 
      let nserror = error as NSError 
      if nserror.code == NSFileReadNoSuchFileError { 
       do { 
        try fileManager.createDirectoryAtPath(self.applicationDocumentsDirectory.path!, withIntermediateDirectories: true, attributes: nil) 
       } catch { 
        failError = nserror 
       } 
      } else { 
       failError = nserror 
      } 
     } 
    }() 
} 

とコアデータ用のSQLiteファイル私はエンティティに新しいレコードを追加した後、どこにもありません。上記のコードには、SQLiteファイルへのポインタはありません。以下はiOSの対応版です。

class AppDelegate: UIResponder, UIApplicationDelegate { 
    // MARK: - Core Data stack 
    lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = { 
     // The persistent store coordinator for the application. This implementation creates and returns a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail. 
     // Create the coordinator and store 
     let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel) 
     let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("SingleViewCoreData.sqlite") 
     var failureReason = "There was an error creating or loading the application's saved data." 
     do { 
      try coordinator.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: nil) 
     } catch { 
      // Report any error we got. 
      var dict = [String: AnyObject]() 
      dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data" 
      dict[NSLocalizedFailureReasonErrorKey] = failureReason 

      dict[NSUnderlyingErrorKey] = error as NSError 
      let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict) 
      // Replace this with code to handle the error appropriately. 
      // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 
      NSLog("Unresolved error \(wrappedError), \(wrappedError.userInfo)") 
      abort() 
     } 

     return coordinator 
    }() 
} 

上記のコードは、SQLiteファイルを指しています。だから私はエンティティにレコードを挿入するのに問題はない。

Xcodeを使用しています。7.2.1何か間違っていますか？またはこれはXcodeのバグですか？

Answer 1

ここに投稿したコードは機能的なコアデータスタックの一部であり、コアデータを初期化するには不十分です。

これは、コアデータスタックを初期化するためのAppleの現在のコード例です：

import CoreData 
class DataController: NSObject { 
    var managedObjectContext: NSManagedObjectContext 
    init() { 
     // This resource is the same name as your xcdatamodeld contained in your project. 
     guard let modelURL = NSBundle.mainBundle().URLForResource("DataModel", withExtension:"momd") else { 
      fatalError("Error loading model from bundle") 
     } 
     // The managed object model for the application. It is a fatal error for the application not to be able to find and load its model. 
     guard let mom = NSManagedObjectModel(contentsOfURL: modelURL) else { 
      fatalError("Error initializing mom from: \(modelURL)") 
     } 
     let psc = NSPersistentStoreCoordinator(managedObjectModel: mom) 
     managedObjectContext = NSManagedObjectContext(concurrencyType: .MainQueueConcurrencyType) 
     managedObjectContext.persistentStoreCoordinator = psc 
     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)) { 
      let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask) 
      let docURL = urls[urls.endIndex-1] 
      /* The directory the application uses to store the Core Data store file. 
      This code uses a file named "DataModel.sqlite" in the application's documents directory. 
      */ 
      let storeURL = docURL.URLByAppendingPathComponent("DataModel.sqlite") 
      do { 
       try psc.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: storeURL, options: nil) 
      } catch { 
       fatalError("Error migrating store: \(error)") 
      } 
     } 
    } 
} 

は、AppleからInitialising the Core Data Stackを参照してください。

Answer 2

@DuncanBabbageソリューションのスウィフト3バージョン：

class DataController: NSObject { 
    var managedObjectContext: NSManagedObjectContext 
    override init() { 
     // This resource is the same name as your xcdatamodeld contained in your project. 
     guard let modelURL = Bundle.main.url(forResource: "DataModel", withExtension:"momd") else { 
      fatalError("Error loading model from bundle") 
     } 
     // The managed object model for the application. It is a fatal error for the application not to be able to find and load its model. 
     guard let mom = NSManagedObjectModel(contentsOf: modelURL) else { 
      fatalError("Error initializing mom from: \(modelURL)") 
     } 
     let psc = NSPersistentStoreCoordinator(managedObjectModel: mom) 
     managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType) 
     managedObjectContext.persistentStoreCoordinator = psc 

     DispatchQueue.global(qos: DispatchQoS.QoSClass.background).async { 
      let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask) 
      let docURL = urls[urls.endIndex-1] 
      /* The directory the application uses to store the Core Data store file. 
      This code uses a file named "DataModel.sqlite" in the application's documents directory. 
      */ 
      let storeURL = docURL.appendingPathComponent("DataModel.sqlite") 
      do { 
       try psc.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: storeURL, options: nil) 
      } catch { 
       fatalError("Error migrating store: \(error)") 
      } 
     } 
    } 
}