Why method updateSearchResultsForSearchController is not called?

Question

I have a UICollectionViewController that maintains a recipes collection.

class RecipesViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout, UICollectionViewDataSource  {

And another UICollectionViewController for maintaining results of the search, also implementing the UISearchResultsUpdating like that:

class SearchResultsController: UICollectionViewController, UISearchResultsUpdating,UICollectionViewDelegateFlowLayout, UICollectionViewDataSource { ...

I need to search into the collection, so I have a member into RecipesViewController

var searchController: UISearchController!

also initiated like that:

let resultsController = SearchResultsController()
resultsController.recipes = recipes
resultsController.filteredResults = recipes

searchController = UISearchController(searchResultsController: resultsController)
searchController.searchResultsUpdater = resultsController

I placed into the header of RecipesViewController the UISearchBar from searchController.

My problem is that SearchResultsController is not updating when text is entered into searchBar. Method updateSearchResultsForSearchController is not even called.

Answer 1

@interface YourViewController_CollectionResults () <UISearchResultsUpdating>

@end

@implementation YourViewController_CollectionResults
- (void)viewDidLoad {

    [super viewDidLoad];

    // The collection view controller is in a nav controller, and so the containing nav controller is the 'search results controller'
    UINavigationController *searchResultsController = [[self storyboard] instantiateViewControllerWithIdentifier:@"CollectionSearchResultsNavController"];

    self.searchController = [[UISearchController alloc] initWithSearchResultsController:searchResultsController];

    //It's really import that you class implement <UISearchResultsUpdating> 
    self.searchController.searchResultsUpdater = self;

    self.tableView.tableHeaderView = self.searchController.searchBar;

    self.definesPresentationContext = YES;

}

You have an example in this github

Sample-UISearchController

I hope that this example solves your problem.