如何在swift中使用CoreData

先创建两个类

import Foundation

import CoreData

class CoreDataStore: NSObject{

let storeName = "News"

let storeFilename = "News.sqlite"

var managedObjectModel: NSManagedObjectModel {

if _managedObjectModel == nil {

let modelURL = NSBundle.mainBundle().URLForResource(storeName, withExtension: "momd")

_managedObjectModel = NSManagedObjectModel(contentsOfURL: modelURL)

}

return _managedObjectModel!

}

var _managedObjectModel: NSManagedObjectModel? = nil

var persistentStoreCoordinator: NSPersistentStoreCoordinator {

if _persistentStoreCoordinator == nil {

let storeURL = self.applicationDocumentsDirectory.URLByAppendingPathComponent(storeFilename)

var error: NSError? = nil

_persistentStoreCoordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)

if _persistentStoreCoordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: storeURL, options: nil, error: &error) == nil {

abort()

}

}

return _persistentStoreCoordinator!

}

var _persistentStoreCoordinator: NSPersistentStoreCoordinator? = nil

// #pragma mark - Documents directory

var applicationDocumentsDirectory: NSURL {

let urls = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)

return urls[urls.endIndex-1] as NSURL

}

}

import CoreData

import UIKit

class CoreDataHelper: NSObject{

let store: CoreDataStore!

override init(){

super.init()

let appDelegate = UIApplication.sharedApplication().delegate as AppDelegate

self.store = appDelegate.cdstore

NSNotificationCenter.defaultCenter().addObserver(self, selector: "contextDidSaveContext:", name: NSManagedObjectContextDidSaveNotification, object: nil)

}

deinit{

NSNotificationCenter.defaultCenter().removeObserver(self)

}

// #pragma mark - Core Data stack

// main thread context

var managedObjectContext: NSManagedObjectContext {

if _managedObjectContext == nil {

let coordinator = self.store.persistentStoreCoordinator

if coordinator != nil {

_managedObjectContext = NSManagedObjectContext(concurrencyType: NSManagedObjectContextConcurrencyType.MainQueueConcurrencyType)

_managedObjectContext!.persistentStoreCoordinator = coordinator

}

}

return _managedObjectContext!

}

var _managedObjectContext: NSManagedObjectContext? = nil

var backgroundContext: NSManagedObjectContext {

if _backgroundContext == nil {

let coordinator = self.store.persistentStoreCoordinator

if coordinator != nil {

_backgroundContext = NSManagedObjectContext(concurrencyType: NSManagedObjectContextConcurrencyType.PrivateQueueConcurrencyType)

_backgroundContext!.persistentStoreCoordinator = coordinator

}

}

return _backgroundContext!

}

var _backgroundContext: NSManagedObjectContext? = nil

// save NSManagedObjectContext

func saveContext (context: NSManagedObjectContext) {

var error: NSError? = nil

if context != nil {

if context.hasChanges &&!context.save(&error) {

NSLog("Unresolved error (error)")

abort()

}

}

}

func saveContext () {

self.saveContext( self.backgroundContext )

}

// call back function by saveContext, support multi-thread

func contextDidSaveContext(notification: NSNotification) {

let sender = notification.object as NSManagedObjectContext

if sender === self.managedObjectContext {

NSLog("======= Saved main Context in this thread")

self.backgroundContext.performBlock {

self.backgroundContext.mergeChangesFromContextDidSaveNotification(notification)

}

} else if sender === self.backgroundContext {

NSLog("======= Saved background Context in this thread")

self.managedObjectContext.performBlock {

self.managedObjectContext.mergeChangesFromContextDidSaveNotification(notification)

}

} else {

NSLog("======= Saved Context in other thread")

self.backgroundContext.performBlock {self.backgroundContext.mergeChangesFromContextDidSaveNotification(notification)

}

self.managedObjectContext.performBlock {

self.managedObjectContext.mergeChangesFromContextDidSaveNotification(notification)

}

}

}

}

在AppDelegate里添加如下代码

// #pragma mark - Core Data Helper

var cdstore: CoreDataStore {

if _cdstore == nil {

_cdstore = CoreDataStore()

}

return _cdstore!

}

var _cdstore: CoreDataStore? = nil

var cdh: CoreDataHelper {

if _cdh == nil {

_cdh = CoreDataHelper()

}

return _cdh!

}

var _cdh: CoreDataHelper? = nil

func applicationWillTerminate(application: UIApplication!) {

self.cdh.saveContext()

}

现在就可以在程序里使用CoreData了。我会建个class将常用 *** 作写在里面。代码如下

import UIKit

import CoreData

class NewsCoreDataController:NSObject {

let store: CoreDataStore!

let cdh: CoreDataHelper!

override init() {

super.init()

let appDelegate = UIApplication.sharedApplication().delegate as AppDelegate

self.store = appDelegate.cdstore

self.cdh = appDelegate.cdh

}

func fetchNewestNews()->NSFetchedResultsController {

var error:NSError? = nil

var fReq:NSFetchRequest = NSFetchRequest(entityName: "News")

var sorter:NSSortDescriptor = NSSortDescriptor(key: "newsDate", ascending: false)

fReq.sortDescriptors = [sorter]

fReq.fetchBatchSize = 20

fReq.fetchLimit = 20

return NSFetchedResultsController(fetchRequest: fReq, managedObjectContext: self.cdh.managedObjectContext, sectionNameKeyPath: nil, cacheName: nil)

}

//按条件检查entity是否有符合条件数据

func fetchOneWithConditionForCheckIfExist(entityName:String,condition:NSPredicate)->[AnyObject]! {

var fetchReq = NSFetchRequest(entityName: entityName)

fetchReq.predicate = condition

fetchReq.fetchLimit = 1

var error:NSError? = nil

return self.cdh.managedObjectContext.executeFetchRequest(fetchReq, error: &error)

}

//检查entity里是否有数据

func fetchOneForCheckIfExist(entityName:String)->[AnyObject]! {

var fetchReq = NSFetchRequest(entityName: entityName)

fetchReq.fetchLimit = 1

var error:NSError? = nil

return self.cdh.managedObjectContext.executeFetchRequest(fetchReq, error: &error)

}

func insertForEntityWithName(entityName:String)->AnyObject! {

return NSEntityDescription.insertNewObjectForEntityForName(entityName, inManagedObjectContext: self.cdh.managedObjectContext)

}

//删除一个entity里的所有数据

func deleteOneEntityAllData(entityName:String) {

var error:NSError? = nil

var fReq:NSFetchRequest = NSFetchRequest(entityName: entityName)

var result = self.cdh.backgroundContext.executeFetchRequest(fReq, error: &error)

println(result.count)

for resultItem in result {

self.cdh.backgroundContext.deleteObject(resultItem as NSManagedObject)

}

self.save()

}

func save() {

self.cdh.saveContext(self.cdh.managedObjectContext)

}

}

这样在程序中就可以很方便简洁的 *** 作CoreData数据了。比如

let cdControl = NewsCoreDataController()

var result = cdControl.fetchOneForCheckIfExist("Sources")

第一步：创建一个 DataDemo.xcdatamodel 文件，在其中建一个实体名字为 Entity1 ，实体中建两个字段 id 和 name。

第二步：为项目添加 CoreData.framework 框架，然后在 .pch 中加入 #import <coredata/coredata.h>

第三步：在 app delegate 中定义 core data 的相关对象（同时完成它们的初始化工作）

.h 文件~

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