如何将Core Data包含到Xcode中已创建的iOS项目中？

Question

我忘了包含核心数据，现在我已经完成了一半的项目，现在想包括它。

现在是否可以包含Core Data？如果有的话，谁能告诉我该怎么做？

Answer 1

Xcode 4.3.2 添加核心数据框架。

选择Target-> Summary Pane-> Linked Frameworks &库。

在上述图像CoreData框架已添加。你可以点击下面的'+'按钮来添加你选择的框架。

一次U CICK ON'+'按钮U'LL看到下面的图像屏幕。

将新文件添加到它去文件 - >新建文件 - > iOS的标签 - > CoreData setion.You可以将文件乌尔选择

Answer 2

添加CoreData框架该项目，然后创建一个.xdatamodeld文件（File-> New-> CoreData-> Data Model）。将其命名为DataModel。然后创建一个单独的类将处理所有的数据持久化操作：

.H

// 
    // 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 

.M

// 
// 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 

Answer 3

无论是hp iOS Coder的和Eugene的答案是正确的！

核心数据文件（或项目）被配置为：

1. 链接，包括核心数据框架（并且这样做在你的项目的.pch文件导入语句）
2. 应用程序的委托头（.h）包括属性声明一个context，model和coordinator（如上）
3. 的app delegate的.M定义saveContext，managedObjectContext，managedObjectModel，persistentStoreCoordinator，applicationDocumentDirectory个函数/方法
4. 的数据模型，如上