Swift中適用於iOS 9和iOS 10的CoreData Stack

Question

我正嘗試將Core Data添加到支持iOS 9+的現有項目中。通過Xcode中產生

我已經添加代碼：

// MARK: - Core Data stack 

    lazy var persistentContainer: NSPersistentContainer = { 

     let container = NSPersistentContainer(name: "tempProjectForCoreData") 
     container.loadPersistentStores(completionHandler: { (storeDescription, error) in 
      if let error = error as NSError? { 

       fatalError("Unresolved error \(error), \(error.userInfo)") 
      } 
     }) 
     return container 
    }() 

    // MARK: - Core Data Saving support 

    func saveContext() { 
     let context = persistentContainer.viewContext 
     if context.hasChanges { 
      do { 
       try context.save() 
      } catch { 
       let nserror = error as NSError 
       fatalError("Unresolved error \(nserror), \(nserror.userInfo)") 
      } 
     } 
    } 

在Xcode生成標準CoreData堆棧後，我發現了新的類NSPersistentContainer的是購自的iOS 10並且作爲結果出現錯誤。

正確的CoreData Stack應該如何支持iOS 9和10？

Answer 1

這是爲我工作的核心數據棧。我認爲爲了支持iOS 10我需要實現NSPersistentContainer類，但是我發現使用NSPersistentStoreCoordinator的舊版本也可以。

您必須更改您的模型（coreDataTemplate）和項目（SingleViewCoreData）的名稱。

斯威夫特3：

// MARK: - CoreData Stack 

    lazy var applicationDocumentsDirectory: URL = { 
     // The directory the application uses to store the Core Data store file. This code uses a directory named "com.cadiridris.coreDataTemplate" in the application's documents Application Support directory. 
     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: "coreDataTemplate", 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 
     managedObjectContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy 
     return managedObjectContext 
    }() 

    // MARK: - Core Data Saving support 

    func saveContext() { 
     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() 
      } 
     } 
    } 

Answer 2

使用接下來的結構適用於iOS 9和10

這是上下文中使用NEX並更換ModelCoreData爲CoreData Storage.share的型號名稱。背景

進口基金會 進口CoreData

/// NSPersistentStoreCoordinator延伸 擴展NSPersistentStoreCoordinator {

/// NSPersistentStoreCoordinator error types 
public enum CoordinatorError: Error { 
    /// .momd file not found 
    case modelFileNotFound 
    /// NSManagedObjectModel creation fail 
    case modelCreationError 
    /// Gettings document directory fail 
    case storePathNotFound 
} 

/// Return NSPersistentStoreCoordinator object 
static func coordinator(name: String) throws -> NSPersistentStoreCoordinator? { 

    guard let modelURL = Bundle.main.url(forResource: name, withExtension: "momd") else { 
     throw CoordinatorError.modelFileNotFound 
    } 

    guard let model = NSManagedObjectModel(contentsOf: modelURL) else { 
     throw CoordinatorError.modelCreationError 
    } 

    let coordinator = NSPersistentStoreCoordinator(managedObjectModel: model) 

    guard let documents = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).last else { 
     throw CoordinatorError.storePathNotFound 
    } 

    do { 
     let url = documents.appendingPathComponent("\(name).sqlite") 
     let options = [ NSMigratePersistentStoresAutomaticallyOption : true, 
         NSInferMappingModelAutomaticallyOption : true ] 
     try coordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: options) 
    } catch { 
     throw error 
    } 

    return coordinator 
} 

}

結構寄存{

static var shared = Storage() 

@available(iOS 10.0, *) 
private lazy var persistentContainer: NSPersistentContainer = { 
    let container = NSPersistentContainer(name: "ModelCoreData") 
    container.loadPersistentStores { (storeDescription, error) in 
     print("CoreData: Inited \(storeDescription)") 
     guard error == nil else { 
      print("CoreData: Unresolved error \(String(describing: error))") 
      return 
     } 
    } 
    return container 
}() 

private lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = { 
    do { 
     return try NSPersistentStoreCoordinator.coordinator(name: "ModelCoreData") 
    } catch { 
     print("CoreData: Unresolved error \(error)") 
    } 
    return nil 
}() 

private lazy var managedObjectContext: NSManagedObjectContext = { 
    let coordinator = self.persistentStoreCoordinator 
    var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType) 
    managedObjectContext.persistentStoreCoordinator = coordinator 
    return managedObjectContext 
}() 

// MARK: Public methods 

enum SaveStatus { 
    case saved, rolledBack, hasNoChanges 
} 

var context: NSManagedObjectContext { 
    mutating get { 
     if #available(iOS 10.0, *) { 
      return persistentContainer.viewContext 
     } else { 
      return managedObjectContext 
     } 
    } 
} 

mutating func save() -> SaveStatus { 
    if context.hasChanges { 
     do { 
      try context.save() 
      return .saved 
     } catch { 
      context.rollback() 
      return .rolledBack 
     } 
    } 
    return .hasNoChanges 
} 
func deleteAllData(entity: String) 
{ 
    // let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate 
    let managedContext = Storage.shared.context 
    let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: entity) 
    fetchRequest.returnsObjectsAsFaults = false 

    do 
    { 
     let results = try managedContext.fetch(fetchRequest) 
     for managedObject in results 
     { 
      let managedObjectData:NSManagedObject = managedObject as! NSManagedObject 
      managedContext.delete(managedObjectData) 
     } 
    } catch let error as NSError { 
     print("Detele all data in \(entity) error : \(error) \(error.userInfo)") 
    } 
} 

}