ZyusAn ZyusAn - 1 year ago 841
iOS Question

"Cannot load NSManagedObjectModel. nil is an illegal URL parameter"

I want to get the managed object context from AppDelegate, but the app crashed after I put the two lines of code into the method even I did nothing else, and there was a message in debug area:"CoreData: Cannot load NSManagedObjectModel. nil is an illegal URL parameter..."

The code added in my method:

AppDelegate *delegate = [UIApplication sharedApplication].delegate;
NSManagedObjectContext *managedObjectContext = delegate.managedObjectContext;

-managedObjectModel method in AppDelegate:

- (NSManagedObjectModel *)managedObjectModel {
// The managed object model for the application. It is a fatal error for the application not to be able to find and load its model.
if (_managedObjectModel != nil) {
return _managedObjectModel;
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"FoodPin" withExtension:@"momd"];
_managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return _managedObjectModel;

and the -managedObjectContext method:

- (NSManagedObjectContext *)managedObjectContext {
// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.)
if (_managedObjectContext != nil) {
return _managedObjectContext;

NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (!coordinator) {
return nil;
_managedObjectContext = [[NSManagedObjectContext alloc]initWithConcurrencyType:NSPrivateQueueConcurrencyType];
[_managedObjectContext setPersistentStoreCoordinator:coordinator];
return _managedObjectContext;

"FoodPin" is my project name.So what's wrong here?I'm new to iPhone programming (Core Data in particular).

Can anyone help me?


Answer Source

The problem is this line:

NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"FoodPin" withExtension:@"momd"];

modelURL is nil meaning that the system couldn't find the resource FoodPin.momd.

Make sure you have a Core Data model in your project named FoodPin. It will appear as FoodPin.xcdatamodeld in the Project Navigator.

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