How to use UISearchController to let users enter search words

Swift version: 5.6

Paul Hudson @twostraws May 28th 2019

UISearchController is a small component designed to make it easy and consistent to add searching to any view controller. Adding it only takes a few small steps:

Embed your view controller in a navigation controller.
Add a conformance to UISearchResultsUpdating.
Create the search controller and assign it to your view controller.
Implement its sole required method: updateSearchResults().

Let’s go through them here. First, open Main.storyboard, select your view controller, then embed it in a navigation controller – go to the Editor menu and choose Embed In > Navigation Controller.

Second, modify your view controller’s definition so that it includes a conformance for UISearchResultsUpdating.

Third, add some code to viewDidLoad() to create the search controller and assign it to the current view controller. The search controller actually belongs as a property of the navigation item of the view controller, which automatically places it inside your navigation bar when the view controller is displayed.

let search = UISearchController(searchResultsController: nil)
search.searchResultsUpdater = self
search.obscuresBackgroundDuringPresentation = false
search.searchBar.placeholder = "Type something here to search"
navigationItem.searchController = search

Finally, implement the updateSearchResults() method to update your search results. This method gets called every time the user types anything into the search bar, so it’s your job to use their new text to filter your data however you want:

func updateSearchResults(for searchController: UISearchController) {
    guard let text = searchController.searchBar.text else { return }
    print(text)
}

That’s it!

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