How do I hide a tableView searchBar - ios

Question

I want to have a searchBar in the tableView that is hidden by default, but if the user pulls down it appears.
So I have used the following code to implement this but when the view is first displayed the searchBar is momentarily visible and I would like avoid this brief flash. Adding self.tableView.contentOffset = CGPointMake(0, 0) to the viewDidLoad() method does not have any affect. Note that the tableView is behind a navigation controller which is why setting the Y offset to 0 effectively hides the searchBar behind the navigation bar. Any idea how to make sure the tableView's headerView is hidden when the view is first be displayed.
I have considered simply removing the headerView but then the user can't drag down to access it.
override func viewDidLoad() {
super.viewDidLoad()
searchBar.delegate = self
searchBar.frame = CGRectMake(0, 0, self.tableView.frame.size.width, 44)
if let tv = self.tableView {
if let headerView = tv.tableHeaderView {
headerView.addSubview(searchBar)
} else {
FLOG("No table header view is available so create one!")
let headerView = UIView()
let width: CGFloat = tv.frame.size.width
headerView.frame = CGRectMake(0, 0, width, 44);
tv.tableHeaderView = headerView
tv.tableHeaderView!.addSubview(searchBar)
}
}
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
dispatch_after(0, dispatch_get_main_queue()) {
self.tableView.contentOffset = CGPointMake(0, 0)
}
}

Answer 1

I think there's an ordering issue with viewWillAppear and viewDidLoad. As I understand, viewWillAppear gets called every time a view will be drawn and added to the view hierarchy, whereas viewDidLoad gets called when a VC loads its subview for the first time.
So, I suppose on your first run the view loads via the mainQueue with viewDidLoad which places your search bar at (0,44), then viewWillAppear gets called but actually causes a brief visual blip due to the call to move the table's offset on the mainQueue. But on subsequent calls, since viewDidLoad has already happened, only viewWillAppear gets called. And since the search bar doesn't first start at (0,44) and then needs to move to (0,0), there's no blip.
Rather than directly defining the frame for the search bar, try calling sizeToFit on it after adding it to the tableHeader. Secondly, I don't believe you have to instantiate the header view, just set it equal to the searchbar. Lastly, take the contentOffset call out of the dispatch_queue, it should be handled correctly by viewWillAppear as is.
I went deep into UISearchController for iOS8 recently, and documented the journey (in part at least). For the code I used, here's a link to the implementation file and the corresponding write-up I did. It's in ObjC, so you'll need to do a little translation. But it looks like:
self.searchController = [[UISearchController alloc] initWithSearchResultsController:self.filteredResultsTableViewController];
self.searchBar = self.searchController.searchBar;
// other code ...
[self.searchBar sizeToFit];
// other code ...
self.tableView.tableHeaderView = self.searchBar;