[objective c] 기존 프로젝트에 core data 추가하기

1. framework에 CoreData.framework 추가
2. Xcode에서 New File -> IOS 탭 -> Core Data(4.3 기준 이하 버전은 아마 Resource) -> Data model
3. delegate 에 아래의 내용을 추가

--- 헤더
#import <CoreData/CoreData.h>

@interface AppDelegate : NSObject <UIApplicationDelegate> {
  NSManagedObjectModel *managedObjectModel;
  NSManagedObjectContext *managedObjectContext;
  NSPersistentStoreCoordinator *persistentStoreCoordinator;

  (...Existing Application Code...)
}

@property (nonatomic, retain, readonly) NSManagedObjectModel *managedObjectModel;
@property (nonatomic, retain, readonly) NSManagedObjectContext *managedObjectContext;
@property (nonatomic, retain, readonly) NSPersistentStoreCoordinator *persistentStoreCoordinator;

- (NSString *)applicationDocumentsDirectory;

(...Existing Application Code...)
@end

--- delegate.m
@implementation AppDelegate
//Explicitly write Core Data accessors
- (NSManagedObjectContext *) managedObjectContext {
  if (managedObjectContext != nil) {
    return managedObjectContext;
  }
  NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
  if (coordinator != nil) {
    managedObjectContext = [[NSManagedObjectContext alloc] init];
    [managedObjectContext setPersistentStoreCoordinator: coordinator];
  }

  return managedObjectContext;
}

- (NSManagedObjectModel *)managedObjectModel {
  if (managedObjectModel != nil) {
    return managedObjectModel;
  }
  managedObjectModel = [[NSManagedObjectModel mergedModelFromBundles:nil] retain];

  return managedObjectModel;
}

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
  if (persistentStoreCoordinator != nil) {
    return persistentStoreCoordinator;
  }
  NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory]
                      stringByAppendingPathComponent: @"<Project Name>.sqlite"]];
  NSError *error = nil;
  persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc]
                                 initWithManagedObjectModel:[self managedObjectModel]];
  if(![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType
                                 configuration:nil URL:storeUrl options:nil error:&error]) {
    /*Error for store creation should be handled in here*/
  }

  return persistentStoreCoordinator;
}

- (NSString *)applicationDocumentsDirectory {
  return [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
}

(...Existing Application Code...)

- (void)dealloc {
  [managedObjectContext release];
  [managedObjectModel release];
  [persistentStoreCoordinator release];

  (...Existing Dealloc Releases...)
}
@end

4. ViewController 에도 아래 내용을 추가

--- 헤더
@interface ViewController : UIViewController <NSFetchedResultsControllerDelegate> {
  NSFetchedResultsController *fetchedResultsController;
  NSManagedObjectContext *managedObjectContext;

(...Existing Application Code...)
}

@property (nonatomic, retain) NSFetchedResultsController *fetchedResultsController;
@property (nonatomic, retain) NSManagedObjectContext *managedObjectContext;
@end

--- ViewController.m
@implementation ViewController
@synthesize fetchedResultsController, managedObjectContext;

(...Existing Application Code...)
@end

5. 아래와 같이 사용
ViewController.managedObjectContext = self.managedObjectContext;