UISearchDisplayController with no results tableView?

Question

Usually, a UISearchDisplayController, when activated, dims the tableView and focuses the searchBar. As soon as you enter text into the searchBar, it creates a searchResultsTableView that displays between the searchBar and the keyboard. The searchDisplayController's delegate gets called when this second UITableView is loaded/shown/hidden/unloaded. Usually it shows live search results or autocompletion entries while typing.

In my app, I want to search a webservice and I don't want to call the webservice for each letter the user enters. Therefore, I want to entirely disable the searchResultsTableView and keep the dimmed black overlay while he enters text. I would then trigger the search (with a loading screen) once he hits the search button.

Just returning zero rows for the searchResultsTableView doesn't look nice since it displays an empty searchResultsTableView with a "no results" message. I tried to hide the table when it appears (searchDisplayController:didLoadSearchResultsTableView:) which works, but the blacked dimmed overlay is also hidden so that the underlying tableView is completely visible again.

Any ideas besides recreating the UISearchDisplayController functionality from scratch?

Answer 1

it should be sufficient to implement the following method in your UISearchDisplayDelegate (which usually is your custom UITableViewController subclass)

- (BOOL) searchDisplayController: (UISearchDisplayController *) controller shouldReloadTableForSearchString: (NSString *) searchString
{
    [self startMyCustomWebserviceSearchAsBackgroundProcessForString: searchString]; //starts new NSThread
    return NO; 
}

have you tried this?

Answer 2

Have you tried this:

[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(_lookup:) object:nil];

[self performSelector:@selector(_lookup:) withObject:txt afterDelay:0.20];

This way, if the user types another char within 1/5sec, you only make one web call.

Answer 3

here is a little trick that i just figured out and also you have to return 0 results while editing searchstring

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString
{
    savedSearchTerm = searchString;

    [controller.searchResultsTableView setBackgroundColor:[UIColor colorWithWhite:0.0 alpha:0.8]];
    [controller.searchResultsTableView setRowHeight:800];
    return NO;
}

i think you'll figure out what to do next

Answer 4

Hello Unknown, I just tried your search display controller trick and it works great but I have a problem, it shows the results but the table view remains dimmed until I hit cancel , is their a way to un(dim) the table view straight after the search button on the keyboard is hit

Please let me know, I need it very soon

Answer 5

Based on user182820's code below is my version. I hide the UISearchDisplayController's table view. When a character is entered in the search box I place a 'dimmed view' so it looks like UISearchDisplayController's 'dimmed view' never went away and then remove it when the search is finished. If you enter some characters and press cancel, the table view briefly goes all white and I don't know how to get around this.

- (void)viewDidLoad {
    ...
    tableViewMask=[UIView new];
    tableViewMask.backgroundColor = [UIColor blackColor];
    tableViewMask.alpha = 0.8;
}

- (void)searchDisplayControllerDidBeginSearch:(UISearchDisplayController *)controller{
    tableViewMask.frame=CGRectMake(self.tableView.frame.origin.x, self.tableView.frame.origin.y+controller.searchBar.frame.size.height, self.tableView.frame.size.width, self.tableView.frame.size.height-controller.searchBar.frame.size.height);
    controller.searchResultsTableView.hidden=YES;
}

- (void)searchDisplayControllerWillEndSearch:(UISearchDisplayController *)controller{
    [tableViewMask removeFromSuperview];
}

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString{
    if (searchString.length==0)
        [tableViewMask removeFromSuperview];
    else 
        [self.tableView addSubview:tableViewMask];
    [searchText autorelease];
    searchText=[searchString retain];
    return NO;
}   

Answer 6

I foud a better way, since there is a bug with the "best answer" - the separator and the "No Results" will be shown when scrolling the black background table.

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString {

    controller.searchResultsTableView.backgroundColor = [UIColor blackColor];
    controller.searchResultsTableView.alpha = 0.8;
    controller.searchResultsTableView.separatorStyle = UITableViewCellSeparatorStyleNone;

    for(UIView *subview in tableView.subviews) {
        if([subview isKindOfClass:UILabel.class]) {
            subview.hidden = YES;
        }
    }

    return NO;
}

- (void) searchBarSearchButtonClicked:(UISearchBar *)searchBar {

    self.searchDisplayController.searchResultsTableView.backgroundColor = [UIColor whiteColor];
    self.searchDisplayController.searchResultsTableView.alpha = 1;
    self.searchDisplayController.searchResultsTableView.separatorStyle = UITableViewCellSeparatorStyleSingleLine;

    for(UIView *subview in tableView.subviews) {
        if([subview isKindOfClass:UILabel.class]) {
            subview.hidden = NO;
        }
    }

    // search results and reload data ....
}