Question

Can someone point me to documentation for the scope buttons on UISearchDisplayController? I’m looking through one of Apple’s examples, TableSearch, and I do not see how they populate the scope bar underneath the UISearchBar. The scope bar has

All, Device, Desktop, Portable

I copied the code from the AppDelegate and the MainViewController. I don’t see how those scope buttons are populated though.

In the appDelegate, I see they set up some Product data (Product has a type and name which are both NSStrings),

- (void)applicationDidFinishLaunching:(UIApplication *)application
{
    // Create and configure the window, navigation controller, and main view controller.

    // Create the master list for the main view controller.
    NSArray *listContent = [[NSArray alloc] initWithObjects:
                         [Product productWithType:@"Device" name:@"iPhone"],
                         [Product productWithType:@"Device" name:@"iPod"],
                         [Product productWithType:@"Device" name:@"iPod touch"],
                         [Product productWithType:@"Desktop" name:@"iMac"],
                         [Product productWithType:@"Desktop" name:@"Mac Pro"],
                         [Product productWithType:@"Portable" name:@"iBook"],
                         [Product productWithType:@"Portable" name:@"MacBook"],
                         [Product productWithType:@"Portable" name:@"MacBook Pro"],
                         [Product productWithType:@"Portable" name:@"PowerBook"], nil];


    // Create and configure the main view controller.
    MainViewController *mainViewController = [[MainViewController alloc] initWithNibName:@"MainView" bundle:nil];
    mainViewController.listContent = listContent;
    [listContent release];

    // Add create and configure the navigation controller.
    UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:mainViewController];
    self.navController = navigationController;
    [mainViewController release];
    [navigationController release];

    // Configure and display the window.
    [window addSubview:navController.view];
    [window makeKeyAndVisible];

Then in their MainViewController class:

/*
     File: MainViewController.m 
 Abstract: Main table view controller for the application. 
  Version: 1.5 

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 */

#import "MainViewController.h"
#import "Product.h"

@implementation MainViewController

@synthesize listContent, filteredListContent, savedSearchTerm, savedScopeButtonIndex, searchWasActive;


#pragma mark - 
#pragma mark Lifecycle methods

- (void)viewDidLoad
{
    self.title = @"Products";

    // create a filtered list that will contain products for the search results table.
    self.filteredListContent = [NSMutableArray arrayWithCapacity:[self.listContent count]];

    // restore search settings if they were saved in didReceiveMemoryWarning.
    if (self.savedSearchTerm)
    {
        [self.searchDisplayController setActive:self.searchWasActive];
        [self.searchDisplayController.searchBar setSelectedScopeButtonIndex:self.savedScopeButtonIndex];
        [self.searchDisplayController.searchBar setText:savedSearchTerm];

        self.savedSearchTerm = nil;
    }

    [self.tableView reloadData];
    self.tableView.scrollEnabled = YES;
}

- (void)viewDidUnload
{
    self.filteredListContent = nil;
}

- (void)viewDidDisappear:(BOOL)animated
{
    // save the state of the search UI so that it can be restored if the view is re-created
    self.searchWasActive = [self.searchDisplayController isActive];
    self.savedSearchTerm = [self.searchDisplayController.searchBar text];
    self.savedScopeButtonIndex = [self.searchDisplayController.searchBar selectedScopeButtonIndex];
}

- (void)dealloc
{
    [listContent release];
    [filteredListContent release];

    [super dealloc];
}


#pragma mark -
#pragma mark UITableView data source and delegate methods

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    /*
     If the requesting table view is the search display controller's table view, return the count of
     the filtered list, otherwise return the count of the main list.
     */
    if (tableView == self.searchDisplayController.searchResultsTableView)
    {
        return [self.filteredListContent count];
    }
    else
    {
        return [self.listContent count];
    }
}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *kCellID = @"cellID";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:kCellID];
    if (cell == nil)
    {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:kCellID] autorelease];
        cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    }

    /*
     If the requesting table view is the search display controller's table view, configure the cell using the filtered content, otherwise use the main list.
     */
    Product *product = nil;
    if (tableView == self.searchDisplayController.searchResultsTableView)
    {
        product = [self.filteredListContent objectAtIndex:indexPath.row];
    }
    else
    {
        product = [self.listContent objectAtIndex:indexPath.row];
    }

    cell.textLabel.text = product.name;
    return cell;
}


- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    UIViewController *detailsViewController = [[UIViewController alloc] init];

    /*
     If the requesting table view is the search display controller's table view, configure the next view controller using the filtered content, otherwise use the main list.
     */
    Product *product = nil;
    if (tableView == self.searchDisplayController.searchResultsTableView)
    {
        product = [self.filteredListContent objectAtIndex:indexPath.row];
    }
    else
    {
        product = [self.listContent objectAtIndex:indexPath.row];
    }
    detailsViewController.title = product.name;

    [[self navigationController] pushViewController:detailsViewController animated:YES];
    [detailsViewController release];
}


#pragma mark -
#pragma mark Content Filtering

- (void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope
{
    /*
     Update the filtered array based on the search text and scope.
     */

    [self.filteredListContent removeAllObjects]; // First clear the filtered array.

    /*
     Search the main list for products whose type matches the scope (if selected) and whose name matches searchText; add items that match to the filtered array.
     */
    for (Product *product in listContent)
    {
        if ([scope isEqualToString:@"All"] || [product.type isEqualToString:scope])
        {
            NSComparisonResult result = [product.name compare:searchText options:(NSCaseInsensitiveSearch|NSDiacriticInsensitiveSearch) range:NSMakeRange(0, [searchText length])];
            if (result == NSOrderedSame)
            {
                [self.filteredListContent addObject:product];
            }
        }
    }
}


#pragma mark -
#pragma mark UISearchDisplayController Delegate Methods

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString
{
    [self filterContentForSearchText:searchString scope:
            [[self.searchDisplayController.searchBar scopeButtonTitles] objectAtIndex:[self.searchDisplayController.searchBar selectedScopeButtonIndex]]];

    // Return YES to cause the search result table view to be reloaded.
    return YES;
}


- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchScope:(NSInteger)searchOption
{
    [self filterContentForSearchText:[self.searchDisplayController.searchBar text] scope:
            [[self.searchDisplayController.searchBar scopeButtonTitles] objectAtIndex:searchOption]];

    // Return YES to cause the search result table view to be reloaded.
    return YES;
}


@end

Answer 1

You can set an array of strings which will be used as the title for each scope button. These can be set in InterfaceBuilder, or in code as follows:

self.mainSearchBar.scopeButtonTitles = [NSArray arrayWithObjects:@"All", @"Device", @"Desktop", @"Portable", nil];

You also need to set the showsScopeBar to YES.

self.mainSearchBar.showsScopeBar = YES;