NSManagedObject and CoreData in swift 3 Xcode 8

Question

我使用Xcode 8和swift 3，我从编辑器菜单，NSManageObjectModel中为我的实体创建NSManagedObject，如何使用这个文件来获取和创建对象，在Xcode 7中我使用核心数据堆栈来创建管理对象，持久存储和... .现在我不知道如何在swift 3中使用core data。

Answer 1

这个下面的核心数据代码在swift 3中使用x code 8和更高版本工作良好，并且部署目标可以低IOS 8和更高版本工作一次尝试。我一步一步地写代码。

在appdelegate中导入Coredata

          import UIKit
          import CoreData

        @UIApplicationMain
    class AppDelegate: UIResponder, UIApplicationDelegate 
              var window: UIWindow?

在appdelegate中添加的代码中，只有当coredata在所有版本的os中工作时，你才需要这个代码

private lazy var applicationDocumentsDirectory: URL = {
  let urls = FileManager.default.urls(for: .documentDirectory, in:
                                  .userDomainMask)
 return urls[urls.count-1]
 }()
 //   Core Data stack

lazy var managedObjectModel: NSManagedObjectModel = {
let modelURL = Bundle.main.url(forResource: "Coredata", withExtension: "momd")!
return NSManagedObjectModel(contentsOf: modelURL)!
}()
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
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 {
    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)
    NSLog("Unresolved error (wrappedError), (wrappedError.userInfo)")
    abort()
  }
   return coordinator
   }()
  lazy var managedObjectContext: NSManagedObjectContext = {
  let coordinator = self.persistentStoreCoordinator
  var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
  managedObjectContext.persistentStoreCoordinator = coordinator
  return managedObjectContext
  }()
 //   Core Data Saving support
     func saveContext () {
     if managedObjectContext.hasChanges {
    do {
        try managedObjectContext.save()
    } catch {
        let nserror = error as NSError
        NSLog("Unresolved error (nserror), (nserror.userInfo)")
        abort()
     }
    }
   }

3。保存数据这就是你需要的数据，然后保存到数据库中您编写下面的代码这个写入ViewControllers类只是再次导入coredata并创建NSManagedObject

      var dataBase = [NSManagedObject]()

    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let managedContext = appDelegate.managedObjectContext
    let entity =  NSEntityDescription.entity(forEntityName:
   "YourEntityName",in:managedContext)
    let activityData = NSManagedObject(entity: entity!,insertInto:
    managedContext)
    activityData.setValue(storeData1, forKey: "attributeKey1")
    activityData.setValue(storeData2, forKey: "attributeKey2")
    do {
        try managedContext.save()
        dataBase.append(activityData)

    } catch let error as NSError  {
        print("Could not save (error), (error.userInfo)")
    }
}

4。在你获取数据的课程中，你写这个代码，这里也是一样的Way just

import coredata and create NSMangedObject
   var getData= [NSManagedObject]()

//获取数据函数getLogsData() {

let appDelegate = UIApplication.shared.delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "YourEntityName")
do {
    let results = try managedContext.fetch(fetchRequest)
     } catch let error as NSError {
    print("Could not fetch (error), (error.userInfo)")
}

}