UISearchDisplayController Text Did Change Lagging Behind - ios

Question

I am trying to search through a list of users in my Parse database. To do so I have a search bar controller and table view. When a user is searching, it seems like the search results are a letter behind. For example if I search "Be" it will show all the names starting with "B" instead of "Be" and when I search "Ben" it shows all the users starting with "Be".
Here is my textDidChange Method:
-(void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText{
NSString *string = searchText;
string = string.lowercaseString;
if(string.length>0){
PFUser *currentUser = [PFUser currentUser];
PFQuery *query = [PFQuery queryWithClassName:#"_User"];
[query whereKey:#"name_lower" containsString:string];
[query whereKey:#"username" notEqualTo:currentUser.username];
[query orderByAscending:#"name_lower"];
[query setLimit:1000];
[query findObjectsInBackgroundWithBlock:^(NSArray *array,NSError *error){
if(!error){
results = [[NSArray alloc]initWithArray:array];
[_mainTableView reloadData];
}else{
[ProgressHUD showError:#"Error Searching"];
}
}];
}else{
NSLog(#"NO RESULTS");
results = nil;
[_mainTableView reloadData];
}
}
Then in my cellforrow:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
if (cell == nil) cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"cell"];
PFUser *user = results[indexPath.row];
[user fetchIfNeeded];
cell.textLabel.text = [NSString stringWithFormat:#"%# - #%#",user[#"name"],user[#"username"]];
cell.detailTextLabel.text = user[#"university"];
}

Answer 1

Hey try to put constraints like this:
[query whereKey:#"name_lower" hasPrefix:string];
instead of
[query whereKey:#"name_lower" containsString:string];
After all I would do it this way:
-(void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText{
NSString *string = searchText;
string = string.lowercaseString;
if(string.length>0){
PFQuery *query = [PFUser query];
[query whereKey:#"name_lower" hasPrefix:string];
[query whereKey:#"username" notEqualTo:[[PFUser currentUser] username]];
[query orderByAscending:#"name_lower"];
[query setLimit:1000];
[query findObjectsInBackgroundWithBlock:^(NSArray *array,NSError *error){
if(!error){
results = array;
[_mainTableView reloadData];
} else {
[ProgressHUD showError:#"Error Searching"];
}
}];
} else {
NSLog(#"NO RESULTS");
results = nil;
[_mainTableView reloadData];
}
}