Question

I have a search bar with a suggestions UITableView that gets populated (using JSON services) as the user types. These service calls need to be made after a delay of 500ms of non-typing. If the user starts to type in this period of 500ms, the current call in the queue needs to be cancelled and the app has to wait another 500ms of non-activity before making another afterDelay call. I know I have to use performSelector:withObject:afterDelay in this entire situation, but I’m not able to get around with proper conditions. I tried using a bunch of bools but it just getting dirty… Any help?

Answer 1

I would use an NSTimer instead of performSelector:withObject:afterDelay:. Detect when the text changes in the UISearchBar and reset the timer.

-(void)viewDidLoad {

    search.delegate = self;

}

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

    [timer invalidate];

    timer = [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:@selector(callTheService) userInfo:nil repeats:NO];

}