UISearchDisplayController with no results tableVie

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

Had the same problem as you, I handled it by a) setting the alpha of the searchResultsTableView to 0 when beginning searching, and then by b) adding/removing the overlayView to the viewController's view. Works like a charm for me.

@interface MyViewController()
//...
@property(nonatomic, retain) UIView *overlayView;
//...
@end

@implementation MyViewController
@synthesize overlayView = _overlayView;

//...

- (void)viewDidLoad
{
    //...

    //define your overlayView
    _overlayView = [[UIView alloc] initWithFrame:CGRectMake(0, 44, 320, 480)];
    _overlayView.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0.8];
}

//hide the searchResultsTableView
- (void)searchDisplayControllerWillBeginSearch:(UISearchDisplayController *)controller
{
    self.searchDisplayController.searchResultsTableView.alpha = 0.0f;
}

//when ending the search, hide the overlayView
- (void) searchDisplayControllerWillEndSearch:(UISearchDisplayController *)controller
{
    [_overlayView removeFromSuperview];
}

//depending on what the user has inputed, add or remove the overlayView to the view of the current viewController 
- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString
{   

    if ([searchString length]>0) 
    {
        [self.view addSubview:_overlayView];
    }
    else
    {
        [_overlayView removeFromSuperview];
    }

    return NO;
}

@end

Answer 2

Nothing of the above seemed to work well in the end, so I came up with the following (you have to call removeTableHeader when you are ready to display your results):

- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar {
    [self setTableHeader];
}

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText {
    [self setTableHeader];
}

- (void)setTableHeader {
    UIView *headerView = [[UIView alloc] initWithFrame:self.searchDisplayController.searchResultsTableView.frame];
    headerView.backgroundColor = [UIColor colorWithWhite:0 alpha:0.8];

    [self.searchDisplayController.searchResultsTableView setBackgroundColor:[UIColor clearColor]];
    [self.searchDisplayController.searchResultsTableView setScrollEnabled:NO];
    [self.searchDisplayController.searchResultsTableView setTableHeaderView:headerView];

    [headerView release];
}

- (void)removeTableHeader {
    [self.searchDisplayController.searchResultsTableView setBackgroundColor:[UIColor whiteColor]];
    [self.searchDisplayController.searchResultsTableView setScrollEnabled:YES];
    [self.searchDisplayController.searchResultsTableView setTableHeaderView:nil];
}

Obviously, it make the table transparent, adds a black/translucent table header with the same size as the table, and disables scrolling on the table so you cannot get above or past the header. As a bonus, you could add something to the header view ('please wait...' or an activity indicator).

Answer 3

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 4

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 ....
}