Delay in UISearchBar being removed when pushing next view controller

Question

Xcode 10.1, Swift 4.2

ViewController A has LargeTitles, UISearchController and UITableView in operation.

When pushing ViewController B (also a TableView) after selecting a TableViewCell, there is a delay in the space that was occupied by the UISearchBar being removed as shown in the animation.

ViewController B also has a UISearchController, but as per usual behaviour, is hidden until the user drags down on the screen.

Does anyone know how to prevent this from happening?

Additional Information & Code:

ViewController A When cell tapped, it pushes ViewController B using a Show (e.g Push) segue on Storyboard with Animates selected. Data is injected using the prepareForSegue method.

performSegue(withIdentifier: "showLogbook", sender: self)

ViewController B:

class LogbookVC: UIViewController, UITableViewDelegate, UITableViewDataSource, UISearchBarDelegate, UISearchResultsUpdating {

    //Extract
    private let searchController = UISearchController(searchResultsController: nil)


    @IBOutlet private var addButton: UIBarButtonItem!
    @IBOutlet private var shareButton: UIBarButtonItem!
    @IBOutlet private var backButton: UIBarButtonItem!
    @IBOutlet private var tableView: UITableView!

    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.delegate = self
        tableView.dataSource = self
        tableView.rowHeight = 75.0
        //loading tableView data
}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    self.navigationController?.navigationBar.prefersLargeTitles = true
    self.definesPresentationContext = true
    configureSearchController()
    fetchAndSortLogEntries()
}

private func configureSearchController() {
    navigationItem.searchController = searchController
    searchController.searchResultsUpdater = self
    searchController.searchBar.scopeButtonTitles = ["Newest", "Oldest"]
    searchController.searchBar.delegate = self
    searchController.searchBar.barStyle = .black
    searchController.searchBar.tintColor = K.Colors.appMid
    searchController.searchBar.keyboardAppearance = .dark
    searchController.searchBar.returnKeyType = .done
    searchController.dimsBackgroundDuringPresentation = false
    let attributes = [NSAttributedString.Key.foregroundColor: K.Colors.appMid]
    UIBarButtonItem.appearance(whenContainedInInstancesOf: [UISearchBar.self]).setTitleTextAttributes(attributes, for: .normal)
    searchController.searchBar.setValue("Reset", forKey: "_cancelButtonText")
    let searchBarCancelButton = searchController.searchBar.value(forKey: "cancelButton") as? UIButton
    searchBarCancelButton?.setTitle("Reset", for: .normal)
}

Can you show us how you're presenting ViewControllerB from A? — Alex Ioja-Yang
I'm guessing the problem is entirely in the second view controller. Are you sure the search bar is initially hidden and not hidden in viewDidAppear for example? — devios1
If I do not configure the searchController in ViewController B then the TableView presents correctly, so the issue is there somewhere. Commenting out various lines in configureSearchController makes no difference, the problem is still present. I will create a basic test project and see if I can recreate the problem there. — rbaldwin

rbaldwin rbaldwin · Accepted Answer · 2019-02-20T17:21:18

I think this is a bug when using LargeTitles and having two UISearchControllers in adjacent ViewControllers.

I found that by adding the UISearchController to the NavigationItem in viewDidAppear fixes the issue, however it has to be added asynchronously otherwise the following fatal error occurs:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Only one palette with a top boundary edge can be active outside of a transition.

This code needs to be added to both ViewControllers, so that the problem behaviour is also prevented when navigating back to ViewController A.

Xcode 10.1, Swift 4.2

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        DispatchQueue.main.async {
            self.navigationItem.searchController = self.searchController
            self.searchController.searchResultsUpdater = self
            self.searchController.searchBar.delegate = self
        }
    }

This code will ensure the NavigationBar is not hidden when the next ViewController appears:

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        navigationController?.isNavigationBarHidden = false
    }

Delay in UISearchBar being removed when pushing next view controller

1 Answers