Question

I am getting this weird exception and I have no clue how to figure out what’s going wrong here

"Serious application error.  **Exception was caught during Core Data change processing.**  This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification.  **Can't look for value (552284302) in string (1070635162, 630076961, 690758344, 714304224, 693603903, 650263092, 552284302); value is not a string  with userInfo (null)**"

My code is as follows:

- (NSFetchedResultsController *)fetchedResultsController {

if (_fetchedResultsController != nil) {
    return _fetchedResultsController;
}

NSManagedObjectContext *context =   [ (MyAppDelegate*)[[UIApplication sharedApplication] delegate]managedObjectContext];

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription 
                               entityForName:@"MyEntityName" inManagedObjectContext:context];
[fetchRequest setEntity:entity];

NSSortDescriptor *sort = [[NSSortDescriptor alloc] 
                          initWithKey:@"distance" ascending:YES];
[fetchRequest setSortDescriptors:[NSArray arrayWithObject:sort]];

[fetchRequest setFetchBatchSize:20];

User *user = [[DatabaseHelper sharedInstance] getUserDetails];
NSString *predicteString = [NSString stringWithFormat:@"isPrivate == %@  AND recepientList contains %@", [NSNumber numberWithBool:YES], user.userId];

if(dootType == UnReadDootType){
    predicteString = [predicteString stringByAppendingString:@" AND state = 'NEW' "];
}


NSPredicate *predicate;
if(senderId != nil && [senderId intValue] > 0){
    predicteString = [predicteString stringByAppendingString:@" AND senderId == %@"];

    predicate = [NSPredicate
                 predicateWithFormat:predicteString, senderId];

}else{
    predicate = [NSPredicate
                 predicateWithFormat:predicteString];
}

[fetchRequest setPredicate:predicate];


NSFetchedResultsController *theFetchedResultsController = 
[[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest 
                                    managedObjectContext:context sectionNameKeyPath:nil 
                                               cacheName:@"MyEntityName"];

self.fetchedResultsController = theFetchedResultsController;
_fetchedResultsController.delegate = self;

[sort release];
[fetchRequest release];
[theFetchedResultsController release];

return _fetchedResultsController;    

}

The NSFetchRequest logs as:

<NSFetchRequest: 0x362350> (entity: MyEntityName; predicate: (isPrivate == 1 AND recepientList CONTAINS 552284302); sortDescriptors: ((
    "(distance, ascending, compare:)"
)); batch size: 20; type: NSManagedObjectResultType; )

So as you can see I am using a predicate like recepientList CONTAINS 552284302
and for one of my record the recepientList has 1070635162, 630076961, 690758344, 714304224, 693603903, 650263092, 552284302 I am storing comma separated userId in the recepientList, so I am not sure why this exception.

Answer 1

The user.userID is being parsed as a numerical value instead of a string. The CONTAINS operator does not understand numerical values.

The predicate that logs as:

(isPrivate == 1 AND recepientList CONTAINS 552284302)

… should log as:

(isPrivate == 1 AND recepientList CONTAINS "552284302")

The former predicate looks for a numerical value while later looks for a string. (Note that the numerical one in isPrivate == 1 is not quoted.)

If user.userID is a NSNumber then getting it’s string value should correct the problem. Try:

NSString *predicteString = [NSString stringWithFormat:@"isPrivate == %@  AND recepientList contains %@", [NSNumber numberWithBool:YES], [user.userId stringValue]];