如何將Core Data包含到Xcode中已創建的iOS項目中？

Question

我忘了包含核心數據，現在我已經完成了一半的項目，現在想包括它。

現在是否可以包含Core Data？如果有的話，誰能告訴我該怎麼做？

Answer 1

Xcode 4.3.2 添加核心數據框架。

選擇Target-> Summary Pane-> Linked Frameworks &庫。

在上述圖像CoreData框架已添加。你可以點擊下面的'+'按鈕來添加你選擇的框架。

一次U CICK ON'+'按鈕U'LL看到下面的圖像屏幕。

將新文件添加到它去文件 - >新建文件 - > iOS的標籤 - > CoreData setion.You可以將文件烏爾選擇

Answer 2

添加CoreData框架該項目，然後創建一個.xdatamodeld文件（File-> New-> CoreData-> Data Model）。將其命名爲DataModel。然後創建一個單獨的類將處理所有的數據持久化操作：

.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

無論是hp iOS Coder的和Eugene的答案是正確的！

核心數據文件（或項目）被配置爲：

1. 鏈接，包括核心數據框架（並且這樣做在你的項目的.pch文件導入語句）
2. 應用程序的委託頭（.h）包括屬性聲明一個context，model和coordinator（如上）
3. 的app delegate的.M定義saveContext，managedObjectContext，managedObjectModel，persistentStoreCoordinator，applicationDocumentDirectory個函數/方法
4. 的數據模型，如上