title: Tab bar doesn't show up iOS
body: <p>Added Tab bar view controller to my project and it doesn't show up in the app, it shows up in interface builder, but not in the app. And when I go to the Cards view controller it shows a black line above toolbar (second pic). What could be the problem here?</p>
  <p><a href="https://i.stack.imgur.com/u72pZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/u72pZ.png" alt="enter image description here" /></a>
  <a href="https://i.stack.imgur.com/xUzPq.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/xUzPq.jpg" alt="enter image description here" /></a></p>
  <pre><code>    class CardsTableViewController: UITableViewController {
          
          var cards: Results&lt;Card&gt;?
          let realm = try! Realm()
          var cardFromResult: Card?
          var alreadyHighLighted: Bool = false
          var cellIndexPath: IndexPath? {
              didSet {
                  if !alreadyHighLighted {
                      DispatchQueue.main.async {
                          self.tableView.scrollToRow(at: self.cellIndexPath!, at: .middle, animated: true)
                          self.tableView.selectRow(at: self.cellIndexPath!, animated: true, scrollPosition: .middle)
                      }
                      DispatchQueue.main.asyncAfter(deadline: .now() + 0.7) {
                          self.tableView.deselectRow(at: self.cellIndexPath!, animated: true)
                          self.alreadyHighLighted = true
                      }
                  }
              }
          }
          var selectedDeck: Deck? {
              didSet {
                  loadCards()
              }
          }
          
          @IBOutlet var reviewButton: UIBarButtonItem!
      
          override func viewDidLoad() {
              super.viewDidLoad()
              navigationItem.title = selectedDeck?.name
              tableView.tableFooterView = UIView()
          }
          
          override func viewWillAppear(_ animated: Bool) {
              super.viewWillAppear(animated)
              tableView.reloadData()
              if cards?.count == 0 {
                  navigationController?.setToolbarHidden(true, animated: false)
              } else {
                  navigationController?.setToolbarHidden(false, animated: false)
              }
          }
          
          override func viewWillDisappear(_ animated: Bool) {
              super.viewDidDisappear(animated)
              navigationController?.setToolbarHidden(true, animated: false)
          }
  }
  </code></pre>