Position of UISearchBar moving down when clicked on iOS10

Question

I have a trouble with a search bar only on iOS 10 (it works well on iOS 11) and I don't know what's going on, it's been several days I'm trying to solve this by myself without success so I hope someone here could tell me what I do wrong. So, initially, my screen is like this

And when I click in the search bar, it goes like that

If I type text, it well displays the results under the search bar. I just don't know where this space between my search bar and the navigation bar comes from. The results of my search is managed by an another viewcontroller declared like this.

let locationSearchTable = storyboard!.instantiateViewController(withIdentifier: "LocationSearchTableViewController") as! LocationSearchTableViewController
    resultSearchController = UISearchController(searchResultsController: locationSearchTable)
    resultSearchController?.searchResultsUpdater = locationSearchTable

A bit of my code, especially where I set up the search bar:

let searchBar = resultSearchController!.searchBar
        searchBar.sizeToFit()
        searchBar.placeholder = "Search for a place or address"
        if #available(iOS 11.0, *) {
            navigationItem.searchController = resultSearchController
            resultSearchController?.dimsBackgroundDuringPresentation = true
        } else {
            searchBar.delegate = self
            searchBar.searchBarStyle = .default
            searchBar.setShowsCancelButton(false, animated: true)
            searchBar.keyboardAppearance = .default
            navigationController?.navigationBar.isTranslucent = false
            searchBar.isTranslucent = false
            resultSearchController?.dimsBackgroundDuringPresentation = false
            mainView.addSubview(searchBar)
        }
        definesPresentationContext = true
        resultSearchController?.hidesNavigationBarDuringPresentation = false
    }

Answer 1

For others who might encounter the same issue, here is my code now and it's working.

    let searchBar = resultSearchController!.searchBar
    searchBar.sizeToFit()
    searchBar.placeholder = "Search for a place or address"
    if #available(iOS 11.0, *) {
        navigationItem.searchController = resultSearchController
        resultSearchController?.hidesNavigationBarDuringPresentation = false
        resultSearchController?.dimsBackgroundDuringPresentation = true
    } else {
        searchBar.searchBarStyle = .default
        searchBar.setShowsCancelButton(false, animated: true)
        searchBar.keyboardAppearance = .default
        navigationController?.navigationBar.isTranslucent = false
        searchBar.barStyle = .default
        searchBar.isTranslucent = false
        resultSearchController?.hidesNavigationBarDuringPresentation = true
        resultSearchController?.dimsBackgroundDuringPresentation = false
        UI_mapView.addSubview(searchBar)
    }
    definesPresentationContext = true
    let currentLocationButtonItem = MKUserTrackingBarButtonItem(mapView: UI_mapView)
    self.navigationItem.rightBarButtonItem = currentLocationButtonItem