Core-Data iPhone: could not locate an NSManagedObjectModel

manpreet Best Answer 2 years ago

I am using Apple's CoreDataBooks sample project as a learning aid for core data.

I modified the app so that when the app loads I show a menu page first - not the Books tableview (RootViewController).

I have done the following:

I created a menu page in interface builder (just a view with a button on it)

The CoreDataBooksAppDelegate.h now looks like this:

// for the menu
@class MenuViewController;

@interface CoreDataBooksAppDelegate : NSObject <UIApplicationDelegate> {

NSManagedObjectModel *managedObjectModel;
NSManagedObjectContext *managedObjectContext;     
NSPersistentStoreCoordinator *persistentStoreCoordinator;

UIWindow *window;
UINavigationController *navigationController;

//for the menu
MenuViewController *viewController;
}

- (IBAction)saveAction:sender;

//for the menu
@property (nonatomic, retain) IBOutlet MenuViewController *viewController;

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

@property (nonatomic, readonly) NSString *applicationDocumentsDirectory;

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet UINavigationController *navigationController;

@end

The CoreDataBooksAppDelegate.m looks like this:

#import "CoreDataBooksAppDelegate.h"
#import "RootViewController.h"
// for the menu
#import "MenuViewController.h"


@implementation CoreDataBooksAppDelegate

@synthesize window;
@synthesize navigationController;

// for the menu
@synthesize viewController;


#pragma mark -
#pragma mark Application lifecycle

- (void)applicationDidFinishLaunching:(UIApplication *)application {

RootViewController *rootViewController = (RootViewController   *)[navigationController  topViewController];
rootViewController.managedObjectContext = self.managedObjectContext;

// for the menu
[window addSubview:viewController.view];

// Configure and show the window
[window makeKeyAndVisible];
}

The rest of CoreDataAppDelegete.m remains unchanged.

In the MenuViewController when the button is clicked, the following action takes place:

RootViewController *modalViewController1 = [[[RootViewController alloc] initWithNibName:nil bundle:nil] autorelease];  
[self presentModalViewController:modalViewController1 animated:YES];