Adding UISearchBar programmatically to UITableView

To add a UISearchBar to a UITableView there are these things to do:

• Declare and initialize UISearchBar
• Declare and initialize the UISearchDisplayController
• Add the searchBar to the tableView
• Implement the UISearchDisplayController delegate
• In the header file I declare my searchBar, searchDisplayController and the arrays that contain the data to display.

ViewController.h:

#import 

@interface ViewController : UITableViewController
{
    NSArray *originalData;
    NSMutableArray *searchData;

    UISearchBar *searchBar;
    UISearchDisplayController *searchDisplayController;
}

@end

I also added 2 delegates to the class: UISearchBarDelegate and UISearchDisplayDelegate, without, the searchBar simply doesn’t work!

Initialize data:

//ViewController.m

- (id)initWithStyle:(UITableViewStyle)style
{
    self = [super initWithStyle:style];
    if (self) {
        NSArray *group1 = [[NSArray alloc] initWithObjects:@"Napoli", @"Juventus", @"Inter", @"Milan", @"Lazio", nil];
        NSArray *group2 = [[NSArray alloc] initWithObjects:@"Real Madrid", @"Barcelona", @"Villareal", @"Valencia", @"Deportivo", nil];
        NSArray *group3 = [[NSArray alloc] initWithObjects:@"Manchester City", @"Manchester United", @"Chelsea", @"Arsenal", @"Liverpool", nil];

        originalData = [[NSArray alloc] initWithObjects:group1, group2, group3, nil];
        searchData = [[NSMutableArray alloc] init];
    }
    return self;
}

Now we need to initialize our two object, I commented the code to explain what I do:

//ViewController.m

- (void)viewDidLoad
{
    [super viewDidLoad];

    searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
/*the search bar widht must be > 1, the height must be at least 44
(the real size of the search bar)*/

    searchDisplayController = [[UISearchDisplayController alloc] initWithSearchBar:searchBar contentsController:self];
/*contents controller is the UITableViewController, this let you to reuse
the same TableViewController Delegate method used for the main table.*/

    searchDisplayController.delegate = self;
    searchDisplayController.searchResultsDataSource = self;
//set the delegate = self. Previously declared in ViewController.h

    self.tableView.tableHeaderView = searchBar; //this line add the searchBar
                                                //on the top of tableView.
}

I decided to skip the part about the tableView cell initialization, you can find it in the downloadable source code. 🙂

When the tableView is ready it’s time to implement the UISearchDisplayControllerDelegate!

The delegate has many methods to control every aspect of the search, but the most important is

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

This method is called every time you insert a new character in the searchBar, you will take the searchString, perform the search through the table elements and return YES.

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString
{
    [searchData removeAllObjects];
    /*before starting the search is necessary to remove all elements from the
      array that will contain found items */

    NSArray *group; 

/* in this loop I search through every element (group) (see the code on top) in
the "originalData" array, if the string match, the element will be added in a
new array called newGroup. Then, if newGroup has 1 or more elements, it will be
added in the "searchData" array. shortly, I recreated the structure of the
original array "originalData". */

    for(group in originalData) //take the n group (eg. group1, group2, group3)
                               //in the original data
    {
        NSMutableArray *newGroup = [[NSMutableArray alloc] init];
        NSString *element;

        for(element in group) //take the n element in the group
        {                    //(eg. @"Napoli, @"Milan" etc.)
            NSRange range = [element rangeOfString:searchString
                                     options:NSCaseInsensitiveSearch];

            if (range.length > 0) { //if the substring match
                [newGroup addObject:element]; //add the element to group
            }
        }

        if ([newGroup count] > 0) {
            [searchData addObject:newGroup];
        }

        [newGroup release];
    }

    return YES;
}

That’s all! This method will perform a full-text search in all element. When the search end the tableView reload itself. See the source code to see other details.

Download source file (Link UPDATED! (04.01.2016) )