自己写 NSManagedObjectModel NSPersistentStoreCoordinator NSManagedObjectContext

#pragma mark -
#pragma mark Core Data stack
- (NSManagedObjectModel *)managedObjectModel {
if (managedObjectModel_ != nil) {
return managedObjectModel_;
}
managedObjectModel_ = [[NSManagedObjectModel mergedModelFromBundles:nil] retain];
return managedObjectModel_;
}
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
if (persistentStoreCoordinator_ != nil) {
return persistentStoreCoordinator_;
}
NSString *dir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,➥
NSUserDomainMask, YES) lastObject];
NSURL *storeURL = [NSURL fileURLWithPath:[dir➥
stringByAppendingPathComponent:@"Shapes.sqlite"]];
NSError *error = nil;
persistentStoreCoordinator_ = [[NSPersistentStoreCoordinator alloc]➥
initWithManagedObjectModel:[self managedObjectModel]];
if (![persistentStoreCoordinator_ addPersistentStoreWithType:NSSQLiteStoreType➥
configuration:nil URL:storeURL options:nil error:&error]) {
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
return persistentStoreCoordinator_;
}
- (NSManagedObjectContext *)managedObjectContext {
if (managedObjectContext_ != nil) {
return managedObjectContext_;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil) {
managedObjectContext_ = [[NSManagedObjectContext alloc] init];
[managedObjectContext_ setPersistentStoreCoordinator:coordinator];
}
return managedObjectContext_;
}