nsmanagedobjectcontext

I have two NSManagedObjectContext s named importContext and childContext . childContext is the child of importContext and both of them are NSPrivateQueueConcurrencyType . To keep things off the main thread, I'm doing a bunch of work on the importContext 's queue. This work involves lots of fetches and saves, so it's convenient to wrap the whole thing inside a performBlockAndWait: of the importContext (it does need to by a synchronous operation because the code I have after the performBlockAndWait depends on its results). At some point during this work, I might need to create new managed

I'm debugging a random SIGTRAP crash right now that just happens in the background. It's probably something that has to do with an NSManagedObjectContext somewhere. Besides that, I'm trying to debug it using an exception breakpoint to at least find out where it's originating from. The only problem is that the crash/breakpoint occurs in a 0 objc_exception_throw, which is no help to me. The data I get back looks like this: libobjc.A.dylib`objc_exception_throw: 0x32a3a960: push {r4, r5, r6, r7, lr} // breakpoint stops here 0x32a3a962: add r7, sp, #12 0x32a3a964: mov r4, r0 0x32a3a966: movs r0,

I keep getting crashes from a save: command on a managedObjectContext. It doesn't even fulfill the NSLog statement so I don't see the unresolved error statement, so I can't figure out what the problem might be. It doesn't happen every time, but only sporadically. Here's the code (which basically wants to increment a counter): if ([[managedObject valueForKey:@"canSee"]boolValue]){ int read = [[managedObject valueForKey:@"timesRead"] intValue] +1; [managedObject setValue:[NSNumber numberWithInt:read] forKey:@"timesRead"]; NSError *error; if (![resultsController.managedObjectContext save:&error])

Ok, I may be in well over my head here, but suspect I am missing something quite fundamental. I have searched on stack and other forums for help on finding a solution. I've tried all the solutions I have found but none work for my situation and I cannot see what I am missing. I have created a CoreData app. All works fine in reading and writing data to the CoreData store using NSManagedObjectContext within my appDelegate. I have checked to see if the NSManagedObjectContext is set in my AppDelegate and it is. After passing it to my only viewController I check to see if it is set and it isn't. So

I created an iOS project and a managed object model ( Model.xcdatamodeld ) with one entity. In application:didFinishLaunchingWithOptions: I want to test if the managed object model exists, however I am getting nil . Do I have to do something special to create the managed object context after I create the managed object model? Any suggestions on what I may be doing wrong? This is the interface @interface AppDelegate : UIResponder <UIApplicationDelegate> { } @property (nonatomic, strong, readonly) NSManagedObjectContext *managedObjectContext; @property (nonatomic, strong, readonly)