So generieren Sie Dummy-Daten zu CoreData mit swift3

Question

Ich habe ein Projekt erstellt, das iOS 8.0 und höher unterstützt. Also ändere ich den Code in AppDelegate leicht.

AppDelegate

// MARK: - Core Data stack 

    @available(iOS 10.0, *) 
    lazy var persistentContainer: NSPersistentContainer = { 
     /* 
     The persistent container for the application. This implementation 
     creates and returns a container, having loaded 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. 
     */ 
     let container = NSPersistentContainer(name: "coreDataTestForPreOS") 
     container.loadPersistentStores(completionHandler: { (storeDescription, error) in 
      if let error = error as NSError? { 
       // Replace this implementation with code to handle the error appropriately. 
       // fatalError() 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. 

       /* 
       Typical reasons for an error here include: 
       * The parent directory does not exist, cannot be created, or disallows writing. 
       * The persistent store is not accessible, due to permissions or data protection when the device is locked. 
       * The device is out of space. 
       * The store could not be migrated to the current model version. 
       Check the error message to determine what the actual problem was. 
       */ 
       fatalError("Unresolved error \(error), \(error.userInfo)") 
      } 
     }) 
     return container 
    }() 

    // iOS 9 and below 
    lazy var applicationDocumentsDirectory: URL = { 

     let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask) 
     return urls[urls.count-1] 
    }() 

    lazy var managedObjectModel: NSManagedObjectModel = { 
     // The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model. 
     let modelURL = Bundle.main.url(forResource: "coreDataTestForPreOS", withExtension: "momd")! 
     return NSManagedObjectModel(contentsOf: modelURL)! 
    }() 

    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.appendingPathComponent("SingleViewCoreData.sqlite") 
     var failureReason = "There was an error creating or loading the application's saved data." 
     do { 
      try coordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: nil) 
     } catch { 
      // Report any error we got. 
      var dict = [String: AnyObject]() 
      dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data" as AnyObject? 
      dict[NSLocalizedFailureReasonErrorKey] = failureReason as AnyObject? 

      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 
    }() 

    lazy var managedObjectContext: NSManagedObjectContext = { 
     // Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail. 
     let coordinator = self.persistentStoreCoordinator 
     var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType) 
     managedObjectContext.persistentStoreCoordinator = coordinator 
     return managedObjectContext 
    }() 

    // MARK: - Core Data Saving support 

    func saveContext() { 

     if #available(iOS 10.0, *) { 

      let context = persistentContainer.viewContext 
      if context.hasChanges { 
       do { 
        try context.save() 
       } catch { 
        // Replace this implementation with code to handle the error appropriately. 
        // fatalError() 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. 
        let nserror = error as NSError 
        fatalError("Unresolved error \(nserror), \(nserror.userInfo)") 
       } 

     } else { 
      // iOS 9.0 and below - however you were previously handling it 
       if managedObjectContext.hasChanges { 
        do { 
         try managedObjectContext.save() 
        } catch { 
         // Replace this implementation 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. 
         let nserror = error as NSError 
         NSLog("Unresolved error \(nserror), \(nserror.userInfo)") 
         abort() 
        } 
       } 

      } 
     } 
    } 

} 

let ad = UIApplication.shared.delegate as! AppDelegate 

@available(iOS 10.0, *) 
let contextAbove = ad.persistentContainer.viewContext 

let contextBelow = ad.managedObjectContext 

Jetzt möchte ich Daten generieren db. Ich benutze eine benutzerdefinierte Funktion dazu.

Funktion

func generateData() { 

      if #available(iOS 10.0, *) { 
       let item1 = Item(context: contextAbove) 
       item1.name = "Alwin" 
      } else { 
       // Fallback on earlier versions 

      } 

     // to save data 
     ad.saveContext() 
    } 

der obige Code ist mir bitte nicht abgeschlossen helfen, es zu vollenden.
In iOS 10 Ich benutze die unten Funktion das kann

func generateData() { 

     let item1 = Item(context: contextAbove) 
     item1.name = "Alwin" 

     // to save data 
     ad.saveContext() 
    } 

Answer 1

Sie Code wie unter

func generateData() { 

     if #available(iOS 10.0, *) { 
      let item1 = Item(context: contextAbove) 
      item1.name = "Alwin" 
     } else { 
      // Fallback on earlier versions 
      let managedObjectContext = contextBelow 
      let entityDesc = NSEntityDescription.entity(forEntityName: "Item", in: managedObjectContext) 
      let item1 = Item(entity: entityDesc!, insertInto: managedObjectContext) 
      item1.name = "Alwin" 
     } 

     // to save data 
     ad.saveContext() 
}