scroll to top of tableview and show large title iOS

Question

I want to scroll to the top of my tableView and also show the largeTitle in the navigationBar when I tap on the tab in the tabbar.

Using the scrollToRow method does not show the largeTitle:

extension TableViewConstroller: UITabBarControllerDelegate {
    func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
        if tabBarController.selectedIndex == 1 {
            let indexPath = IndexPath(row: 0, section: 0)
            tableView.scrollToRow(at: indexPath, at: .top, animated: true)
        }
    }
}

I also tried

self.tableView.scrollRectToVisible(CGRect(x: 0, y: -64, width: 1, height: 1), animated: true)

This works sometimes, but if I scroll way down the tableView, the navigationBar is still collapsed when this method scrolls up.

What can I do to mimic the behavior of the tableView's scrollsToTop property that does scroll to the top and shows the largeTitle? It animates very smoothly and always shows the large navigationBar.

Have you set `prefersLargeTitles` for your `navigationBar` ? — koen, Mar 11 '20 at 15:06
please see this. https://stackoverflow.com/questions/50625225/ios-11-scroll-to-top-when-using-large-titles-doesnt-work-properly — Muhammad Shahzad, Mar 11 '20 at 15:37
@SidShehxad that question is based on a scrollView, I have a tableView — WalterBeiter, Mar 12 '20 at 06:30
@WalterBeiter `UITableView` is a subclass of `UIScrollView` so it may well be applicable. — koen, Mar 12 '20 at 11:27

score 1 · Answer 1 · answered Mar 16 '20 at 10:02

I used these two methods inside the UITabBarControllerDelegate: The second method searches for the first scrollView and then scrolls to the top on that scrollView. And since a tableView is also a scrollView, this approach works.

func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
    if tabBarController.selectedViewController == viewController {
        if let scrollView = findScrollView(in: viewController.view) {
            let desiredOffset = CGPoint(x: 0, y: -scrollView.contentInset.top - 96 + UIApplication.shared.statusBarFrame.height)
            scrollView.setContentOffset(desiredOffset, animated: true)
        }
    }
    return true
}

private func findScrollView(in view: UIView) -> UIScrollView? {
    if let scrollView = view as? UIScrollView {
        return scrollView
    } else {
        for subview in view.subviews {
            if let scrollView = findScrollView(in: subview) {
                return scrollView
            }
        }
    }
    return nil
}

I am aware of that but you should get it dynamically and not hardcode it — Tristan Richard, Mar 21 '20 at 07:56
When and where can I get that dynamically? I need a precise moment where I can get the height of a large navigationBar. Or is there a constant somewhere in UIkit where I can read that value from? — WalterBeiter, Mar 22 '20 at 11:16
cannot find that edit anymore, so I don't know what you wanted to change — WalterBeiter, Mar 23 '20 at 10:23

scroll to top of tableview and show large title iOS

1 Answers1