Table View Insert error - objective-c

Question

Hi guys i get this error when i try to add to a empty table view : insert row 0 into section 0, but there are only 0 rows in section 0 after the update. Any thoughts?
dispatch_queue_t fetchQ = dispatch_queue_create("Blog Fetcher", NULL);
dispatch_async(fetchQ, ^{
//pull this call out to Blog+twitter later saving should only take
//place in the model!
[document.managedObjectContext performBlock:^
{
NSArray* resultsArray = [self.tweets objectForKey:#"results"];
for (NSDictionary* internalDict in resultsArray)
{
User *user = [NSEntityDescription
insertNewObjectForEntityForName:#"User"inManagedObjectContext:self.context];
user.username =[internalDict objectForKey:#"from_user_name"];
[self.context save:nil];
self.list = [self.list arrayByAddingObject:user];
NSLog(#" indexpath set here %i",self.list.count-1);
NSIndexPath *newIndexpath =[NSIndexPath indexPathForRow:self.list.count-1 inSection:0];
[self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexpath] withRowAnimation:UITableViewRowAnimationAutomatic];
}
}];
});
dispatch_release(fetchQ);
}

Answer 1

My first thought is that you should dispatch updates to the main thread. I'm not sure about your implementation details, but you may also need to move [self.context save:nil] to the main thread also.
NSArray* resultsArray = [self.tweets objectForKey:#"results"];
NSMutableArray *users = [NSMutableArray arrayWithCapacity:resultsArray.count];
NSMutableArray *indexPaths = [NSMutableArray arrayWithCapacity:resultsArray.count];
NSInteger row = self.list.count;
for (NSDictionary* internalDict in resultsArray)
{
User *user = [NSEntityDescription insertNewObjectForEntityForName:#"User"inManagedObjectContext:self.context];
user.username =[internalDict objectForKey:#"from_user_name"];
[self.context save:nil];
[users addObject:user];
NSLog(#" indexpath set here %i", row);
NSIndexPath *newIndexpath =[NSIndexPath indexPathForRow:row inSection:0];
row++;
[indexPaths addObject:newIndexpath];
}
dispatch_async(dispatch_get_main_queue(), ^{
self.list = [self.list arrayByAddingObjectsFromArray:users];
[self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexpath] withRowAnimation:UITableViewRowAnimationAutomatic];
};