I have tried a lot of different answers, but I just can't seem to get this to work. I am trying to add Core Data to an existing Tab Based Project that I have. I added the core data framework through the targets, I set up the DataModel and entities correctly, but I can't seem to access it. I have gotten many different errors, but the most recent is:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Cannot create an NSPersistentStoreCoordinator with a nil model'
I set up a new utility based project using the preset Core Data and copied the code as directly. I simply changed the File URL name to what current project is and it doesn't work. Here is my code:
appDelegate.h
#import <UIKit/UIKit.h>
@interface AppDelegate : UIResponder <UIApplicationDelegate>
{
BOOL isNotFirstTime;
NSMutableArray *teamMembers;
NSMutableArray *projects;
NSMutableArray *tasks;
}
@property(readwrite, retain) NSMutableArray *teamMembers;
@property(readwrite, retain) NSMutableArray *projects;
@property(nonatomic, retain) NSMutableArray *tasks;
@property(nonatomic)BOOL isNotFirstTime;
@property (strong, nonatomic) UIWindow *window;
@property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;
@property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;
@property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;
- (void)saveContext;
- (NSURL *)applicationDocumentsDirectory;
- (NSURL *)applicationDocumentsDirectory;
- (void)saveContext;
@end
AppDelegate.m For some reason when I create the File URL it remains null.....I have no idea why..
#import "AppDelegate.h"
#import "Task.h"
#import "Project.h"
#import "TeamMember.h"
#import "newTeamMemberWindow.h"
@implementation AppDelegate
@synthesize window = _window;
@synthesize tasks;
@synthesize teamMembers;
@synthesize projects;
@synthesize isNotFirstTime;
@synthesize managedObjectContext = __managedObjectContext;
@synthesize managedObjectModel = __managedObjectModel;
@synthesize persistentStoreCoordinator = __persistentStoreCoordinator;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
NSManagedObjectContext *context = [self managedObjectContext];
if (!context) {
NSLog(@"No Context on App Load");
}
newTeamMemberWindow *newTeamMemberWindowObject = [[newTeamMemberWindow alloc]init];
newTeamMemberWindowObject.managedObjectContext = context;
return YES;
}
//Removed all normal methods to consolidate code on stack overflow
#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;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil)
{
__managedObjectContext = [[NSManagedObjectContext alloc] init];
[__managedObjectContext setPersistentStoreCoordinator:coordinator];
}
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;
}
This part the modelURL remains Null.....
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"TimeLines" withExtension:@"momd"];
__managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
NSLog(@"Created managedObjectModel with Url: %@", 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 (__persistentStoreCoordinator != nil)
{
return __persistentStoreCoordinator;
}
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"TimeLines.sqlite"];
NSError *error = nil;
__persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
if (![__persistentStoreCoordinator 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.
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]);
abort();
}
return __persistentStoreCoordinator;
}
#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
