UISearchController weird behavior on dismissing it

Question

I am adding UISearchController searchBar to the controllers' view like this: self.view.addSubview(searchController.searchBar). The functionality is working perfectly fine except that upon selection of the tableview row the searchbar quickly moves down and reappears from the top. I tried the following things, none of which worked out:

1. Setting tableView.tableHeaderView = searchController.searchBar instead of directly adding to the view
2. Adding searchController.searchBar to a separate view that I dragged to the controller setting up constraints on it. Tried clipping to bounds both the newly created view and the searchBar.
3. Embedding the controller in UINavigationViewController and setting self.navigationItem.titleView = searchController.searchBar. I defined the frame of the searchBar, still nothing.
4. Tried playing with Extend Edges feature in the storyboard (Under top bars, etc.), but no selection worked out

5. Adding lines (to viewDIdLoad):

   self.extendedLayoutIncludesOpaqueBars = true

   self.definesPresentationContext = true

Any help would be greatly appreciated.

Answer 1

After trying all of the suggestion and searching over the internet, it caught my eye that the working examples of the UISearchController implementation are done in UITableViewController, but I had UIViewController with UITableViewDataSource and UITableViewDelegate protocols on it. Unfortunately, due to app architecture I was not able to directly have UITableViewController, so I needed to restructure the app, so that it had UINavigationController where I embeded the searchBar in navigationItem.titleView (and not set it as tableView.tableHeaderView like they always do in various tutorials since I needed the searchBar to be fixed, not hidden when we do scrolling) and it worked. Here is how the ultimate working app architecture looks like:

The TrainingContainerViewController has two Container Views, in one we embed TrainingFilterTableViewController that shows up the ultimate results of the autocomplete functionality (after clicking on an autocomplete row). Another Container View embeds UINavigationController (to the left) which, in turn, has TrainingSearchTableViewController as its child.

The code that sets up the UISearchController and its searchBar is located in the TrainingSearchTableViewControllers' viewDidLoad and is the following:

override func viewDidLoad() {
    super.viewDidLoad()

    searchController.searchResultsUpdater = self
    searchController.hidesNavigationBarDuringPresentation = false
    searchController.dimsBackgroundDuringPresentation = false
    searchController.searchBar.sizeToFit()
    searchController.delegate = self
    navigationItem.titleView = searchController.searchBar
    tableView.hidden = true

    ...
}

Nothing else was needed to fix the bug in XCode 8.2.1 and Swift 2.3, just change architecture, so that usage of UITableViewController is possible in the app and use it instead of UIViewController.