Question

I have a controller where the user searches for locations pulled from a Core Data store. To keep the UI responsive I fetch the object IDs on a background thread, like so:

-(void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText
{
    [self performSelectorInBackground:@selector(fetchLocationIDsForSearchTerm:)
                           withObject:searchText];
}

-(void) fetchLocationIDsForSearchTerm:(NSString *) searchTerm
{
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    NSManagedObjectContext *context = <a new context for this thread>        
    NSArray *locationIDs = <a CoreData query which returns object IDs>

    [self performSelectorOnMainThread:@selector(didFetchLocationIDs:) withObject:locationIDs waitUntilDone:YES];
    [context release];
    [pool release];
}

-(void) didFetchLocationIDs:(NSArray*) theLocationIDs
{   
    NSMutableArray *newLocations = [NSMutableArray array];

    for (NSManagedObjectID *objectID in theLocationIDs)
    {
        [newLocations addObject:[[self managedObjectContext] objectWithID:objectID]];
    }

    self.locations = newLocations;
    [[self mainTableView] reloadData];
}

…and then I pull the data out of self.locations in tableView:cellForRowAtIndexPath:.

I would expect that the table would update when the results come back; but instead, it seems to update when the user enters the next letter of their search. Why isn’t [[self mainTableView] reloadData] reloading the table?

UPDATE

I’m using a UISearchBar with SearchDisplayController. If I remove the SearchDisplayController, the problem goes away. Is there some property of the SearchDisplayController I should be using instead?

Answer 1

Because you have two tables.

Table 1 is created by you.

Table 2 is created by the search display controller and is displayed above your table view while a search is taking place. (Read the Overview section of the documentation carefully, it’s tripped my up in the past with this very problem!)

Try changing your line to this :

[[[self searchDisplayController] searchResultsTableView] reloadData];