Question

I am implementing mobile local search in iPhone application:

    - (void)searchBar:(UISearchBar *)theSearchBar textDidChange:(NSString *)searchText {

        //Remove all objects first.
        [copyListOfItems removeAllObjects];

        if([searchText length] > 0) {

            [ovController.view removeFromSuperview];
            searching = YES;
            letUserSelectRow = YES;
            self.tableView.scrollEnabled = YES;
            [self searchTableView];
        }
        else {

            [self.tableView insertSubview:ovController.view aboveSubview:self.parentViewController.view];

            searching = NO;
            letUserSelectRow = NO;
            self.tableView.scrollEnabled = NO;
        }

        [self.tableView reloadData];
    }



    - (void) searchTableView {

        NSString *searchText = searchBar.text;
        NSMutableArray *searchArray = [[NSMutableArray alloc] init];

        for (NSDictionary *dictionary in listOfItems)
        {
            NSArray *array = [dictionary objectForKey:@"key_pdescription"];
            [searchArray addObjectsFromArray:array];
        }

//in requirement searchArray has more than 50k objects
        for (NSString *sTemp in searchArray)
        {
            NSRange titleResultsRange = [sTemp rangeOfString:searchText options:NSCaseInsensitiveSearch];

            if (titleResultsRange.length > 0)
                [copyListOfItems addObject:sTemp];
        }

        [searchArray release];
        searchArray = nil;
    }

It’s working fine for hundreds of records,but I have to implement for 50 thousands or more than that,that search is very very slow after typing 1 character I have to wait to enter next character.
I want to if someone has implemented some optimized algorithm for mobile local search,please guide me how to proceed.

Answer 1

you can use core data and limit the fetch result and populate the data on search result screen,and you can implementat pagination for the next set of records.

NSFetchRequest *request = [[NSFetchRequest alloc] init];
//[request setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"predicateformart"];
[request setPredicate:predicate];
[request setFetchLimit:100];//100 records for example