How to mimic `UITableViewController` showing of the large titles in `navigationBar` on iOS 11

Question

I'm trying to use

prefersLargeTitles

from iOS 11 in my application. It works as expected in subclasses of

UITableViewController

:

navigationController?.navigationBar.prefersLargeTitles = true

However, in one case I needed to subclass

UIViewController

and add a table view myself. In this situation I needed to constraint the table to the view myself:

tableView.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor).isActive = true

tableView.leftAnchor.constraint(equalTo: self.view.leftAnchor).isActive = true

tableView.rightAnchor.constraint(equalTo: self.view.rightAnchor).isActive = true

tableView.bottomAnchor.constraint(equalTo: self.otherView.topAnchor).isActive = true

While these constraints present the

tableView

as I would expect, now the navigation bar always uses large title. I would like to mimic the behavior of the

UITableViewController

, so that when the

tableView

is scrolled to top, the large title is presented, otherwise the title collapses into the normal one.

How to solve this?

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Answer 1

Seems that I have been able to emulate this behavior more or less closely enough. Implementing the delegate method for the tableView that reacts to scrolling, and then running the code that uses current contentOffset to either show, or hide the large title (UITableView inherits from UIScrollView, so the scrollView parameter refers in this case to the tableView):

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    if scrollView.contentOffset.y <= 0 {
        self.navigationItem.largeTitleDisplayMode = .always
    } else {
        self.navigationItem.largeTitleDisplayMode = .never
    }
    self.navigationController?.navigationBar.setNeedsLayout()
    self.view.setNeedsLayout()
    UIView.animate(withDuration: 0.25, animations: {
        self.navigationController?.navigationBar.layoutIfNeeded()
        self.view.layoutIfNeeded()
    })
}

How to mimic `UITableViewController` showing of the large titles in `navigationBar` on iOS 11

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