tableView.setContentOffset not working on UITableView embedded in UIViewcontroller - ios

Question

I had this code in a UITableViewController and it worked perfectly.
func setupSearchBar() {
let searchBar: UISearchBar = searchController.searchBar
tableView.tableHeaderView = searchBar
let point = CGPoint(x: 0, y: searchBar.frame.size.height)
tableView.setContentOffset(point, animated: true
}
Now I'm refactoring my code to fit more of an MVC style architecture. What I did is create a UITableView in the View class:
class View: UIView {
lazy var tableView: UITableView = {
let table = UITableView()
table.translatesAutoresizingMaskIntoConstraints = false
return table
}()
func configureView() {
// tableView
addSubview(tableView)
tableView.centerXAnchor.constraint(equalTo: centerXAnchor).isActive = true
tableView.centerYAnchor.constraint(equalTo: centerYAnchor).isActive = true
tableView.widthAnchor.constraint(equalTo: widthAnchor).isActive = true
tableView.heightAnchor.constraint(equalTo: heightAnchor).isActive = true
}
}
and then use the View class in my ViewController:
class ViewController: UIViewController {
var newView: View! { return self.view as! View }
override func loadView() {
view = View(frame: UIScreen.main.bounds)
newView.configureView()
}
override func viewDidLoad() {
super.viewDidLoad()
setupSearchBar()
}
func setupSearchBar() {
let searchBar: UISearchBar = searchController.searchBar
newView.tableView.tableHeaderView = searchBar
let point = CGPoint(x: 0, y: searchBar.frame.size.height)
newView.tableView.setContentOffset(point, animated: true)
}
The tableView shows up no problem and everything else is fine. The only thing that's not working is the setContentOffset is being called, but it's not offsetting the content. I want the searchbar to be hidden by default when the user first opens this viewController (similar to iMessage), but after I moved the code from a UITableViewController to separate files (UIView + UIViewController) like in this example, the searchbar always shows by default.
I'm not sure why it's not working. Any help would be greatly appreciated.

Answer 1

It's probably a timing problem relative to layout. Instead of calling setUpSearchBar in viewDidLoad, do it later, in viewDidLayoutSubviews, when initial layout has actually taken place. This method can be called many times, so use a flag to prevent it from being called more than once:
var didSetUp = false
override func viewDidLayoutSubviews() {
if !didSetUp {
didSetUp = true
setUpSearchBar()
}
}
Also: Your animated value is wrong:
newView.tableView.setContentOffset(point, animated: true)
You mean false. You don't want this movement to be visible. The table view should just appear with the search bar out of sight.