Iphone 如何将核心数据包含到Xcode中已创建的iOS项目中？

我忘了包括核心数据，现在我已经完成了项目的一半，现在想包括它

现在是否可以包含核心数据？如果是这样，有人能告诉我怎么做吗？

Xcode 4.3.2 添加核心数据框架

选择目标->摘要窗格->链接的框架和库

在上图中，已经添加了CoreData框架。 你可以点击它下面的“+”按钮来添加你选择的框架

一旦点击“+”按钮，您将看到下面的图像屏幕

要向其中添加新文件，请转到文件->新文件->iOS选项卡->核心数据设置。您可以选择文件

---

将CoreData framework添加到项目中，然后创建一个.xdatamodeld文件（文件->新建->CoreData->数据模型）。将其命名为DataModel。然后创建一个将处理所有数据持久性操作的单例类：

h

和的答案都是正确的

核心数据文件（或项目）配置为：

链接到核心数据框架并将其包括在内（在项目的

.pch

文件中作为导入语句）

应用程序委托头（.h）包括声明

上下文

、

模型

和

协调器

的属性（如上所述）

app委托

的.m定义了

saveContext

，

managedObjectContext

，

managedObjectModel

，

persistentStoreCoordinator

，

applicationDocumentDirectory

函数/方法

数据模型，如上所述

---

还可以将编辑器样式更改为图形视图，然后只需按（+添加实体）符号即可添加实体。另外，为了为这个特定实体生成合适的NSManagedObject子类，选择该实体，然后在XCode->Create NSManagedObject子类中选择“Editor”选项…，它将为该实体创建coresponding.h&.m文件。非常棒！我是ios新手，一天中的大部分时间都在尝试在应用程序委托中反复实现数据故障，获取上下文，将其传递给视图控制器，啊！这是甜蜜和完美的工作！这比将代码放入应用程序委托要好得多！

    //
    //  DataAccessLayer.h
    //  
    //
    //  Copyright (c) 2012 __MyCompanyName__. All rights reserved.
    //

    #import <Foundation/Foundation.h>
    #import <CoreData/CoreData.h>

    @interface DataAccessLayer : NSObject

    @property (strong, nonatomic) NSManagedObjectContext *managedObjectContext;
    @property (strong, nonatomic) NSManagedObjectModel *managedObjectModel;
    @property (strong, nonatomic) NSPersistentStoreCoordinator *storeCoordinator;

    + (DataAccessLayer *)sharedInstance;
    - (void)saveContext;

    @end

//
//  DataAccessLayer.m
//  
//
//  Created by admin on 2/27/12.
//  Copyright (c) 2012 __MyCompanyName__. All rights reserved.
//

#import "DataAccessLayer.h"
@interface DataAccessLayer ()
- (NSURL *)applicationDocumentsDirectory;
@end

@implementation DataAccessLayer
@synthesize storeCoordinator;
@synthesize managedObjectModel;
@synthesize managedObjectContext;

+ (DataAccessLayer *)sharedInstance {
  __strong static DataAccessLayer *sharedInstance = nil;
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    sharedInstance = [[DataAccessLayer alloc] init];
    sharedInstance.storeCoordinator = [sharedInstance persistentStoreCoordinator];
    sharedInstance.managedObjectContext = [sharedInstance managedObjectContext];
  });
  return sharedInstance;
}

#pragma mark - Core Data

- (void)saveContext {
  NSError *error = nil;
  if (managedObjectContext != nil)
  {
    if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error])
    {
      NSLog(@"error: %@", error.userInfo);
      /*
       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. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button.
       */
      NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
      UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Oops!"
                                                      message:@"Something has gone terribly wrong! You need to reinstall the app in order for it to work properly."
                                                     delegate:nil
                                            cancelButtonTitle:@"Close."
                                            otherButtonTitles:nil, nil];
      [alert show];
    } 
  }
}

#pragma mark Core Data stack

/**
 Returns the managed object context for the application.
 If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application.
 */
- (NSManagedObjectContext *)managedObjectContext {
  if (managedObjectContext != nil)
  {
    return managedObjectContext;
  }

  if (storeCoordinator != nil)
  {
    self.managedObjectContext = [[NSManagedObjectContext alloc] init];
    [managedObjectContext setPersistentStoreCoordinator:storeCoordinator];
  }
  return managedObjectContext;
}

/**
 Returns the managed object model for the application.
 If the model doesn't already exist, it is created from the application's model.
 */
- (NSManagedObjectModel *)managedObjectModel {
  if (managedObjectModel != nil)
  {
    return managedObjectModel;
  }
  NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"DataModel" withExtension:@"momd"];
  self.managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
  return managedObjectModel;
}

/**
 Returns the persistent store coordinator for the application.
 If the coordinator doesn't already exist, it is created and the application's store added to it.
 */
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
  if (storeCoordinator != nil)
  {
    return storeCoordinator;
  }

  NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"model.sqlite"];

  NSError *error = nil;
  self.storeCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
  if (![storeCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error])
  {
    /*
     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. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button.

     Typical reasons for an error here include:
     * The persistent store is not accessible;
     * The schema for the persistent store is incompatible with current managed object model.
     Check the error message to determine what the actual problem was.


     If the persistent store is not accessible, there is typically something wrong with the file path. Often, a file URL is pointing into the application's resources directory instead of a writeable directory.

     If you encounter schema incompatibility errors during development, you can reduce their frequency by:
     * Simply deleting the existing store:
     [[NSFileManager defaultManager] removeItemAtURL:storeURL error:nil]

     * Performing automatic lightweight migration by passing the following dictionary as the options parameter: 
     [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption, [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];

     Lightweight migration will only work for a limited set of schema changes; consult "Core Data Model Versioning and Data Migration Programming Guide" for details.

     */
    NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Oops!"
                                                    message:@"Something has gone terribly wrong! You need to reinstall the app in order for it to work properly."
                                                   delegate:nil
                                          cancelButtonTitle:@"Close."
                                          otherButtonTitles:nil, nil];
    [alert show];
  }    

  return storeCoordinator;
}

#pragma mark Application's Documents directory

/**
 Returns the URL to the application's Documents directory.
 */
- (NSURL *)applicationDocumentsDirectory {
  return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}


@end