iphone - Xcodeですでに作成されているiOSプロジェクトにCoreDataを含めるにはどうすればよいですか？

Question

Core Dataを含めるのを忘れていましたが、プロジェクトの半分を完了したので、今すぐ含めたいと思います。

今コアデータを含めることは可能ですか？もしそうなら、誰かがそれを行う方法を教えてもらえますか？

Answer 1

Xcode4.3.2コアデータフレームワークを追加します。

[ターゲット]->[概要ペイン]->[リンクされたフレームワークとライブラリ]を選択します。

上記の画像では、CoreDataFrameworkがすでに追加されています。その下にある[+]ボタンをクリックして、選択したフレームワークを追加できます。

一度UCICKON'+'ボタンU'LL下の画像画面を参照してください。

新しいファイルを追加するには、[ファイル]->[新しいファイル]->[iOS]タブ->[CoreData]設定に移動します。任意のファイルを選択できます。

Answer 2

CoreDataフレームワークをプロジェクトに追加してから、.xdatamodeldファイルを作成します（[ファイル]->[新規]->[CoreData]-> [データモデル]）。DataModelという名前を付けます。次に、すべてのデータ永続化操作を処理するシングルトンクラスを作成します。

.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

hp iOSCoderとEugeneの両方の答えは正しいです！

コアデータファイル（またはプロジェクト）は、次のように構成されます。

1. コアデータフレームワークにリンクして含める（プロジェクトの.pchファイルにインポートステートメントとして含める）
2. アプリデリゲートヘッダー（.h）には、、、および（上記のように）を宣言するプロパティが含まれcontextてmodelいcoordinatorます
3. app delegate's .mは、、、、、関数/メソッドを定義saveContextしますmanagedObjectContextmanagedObjectModelpersistentStoreCoordinatorapplicationDocumentDirectory
4. 上記のようなデータモデル