title: Using UISearchController with UINavigationController
body: <p>I'm having the same problem as <a href="https://stackoverflow.com/questions/29472011/uisearchcontroller-persisting-after-segue">here</a>, which doesn't have any answers. (Setting <code>searchController.active</code> to <code>false</code> clears out the search text, which I don't want.) I want to use a UISearchController so that users can search through the list of items in my UITableView. I have a show segue hooked up in the Interface Builder that triggers when the table view's cell is selected.
   The problem is that if the user searches for something and then clicks on a cell of the table, when it segues to the new view, the search bar just sits there. Ideally, I would like the navigation bar to be "replaced" by the search bar while the user is searching, then have the navigation bar return when the user clicks on a cell, and then have the search bar come back when the user clicks the "Back" button. (This is the way the now-deprecated UISearchDisplayController would work.) How can I accomplish this? Here is the controller for my table view.</p>
  
  <pre><code>class ItemSearchViewController: UITableViewController, UISearchResultsUpdating
  {
      var searchController: UISearchController?
  
      let itemList = [ItemList(category:"Chocolate", name:"chocolate Bar", price: 1234),
      ItemList(category:"Chocolate", name:"chocolate Chip", price: 1234),
      ItemList(category:"Chocolate", name:"dark chocolate", price: 1234),
      ItemList(category:"Hard", name:"lollipop", price: 1234),
      ItemList(category:"Hard", name:"candy cane", price: 1234),
      ItemList(category:"Hard", name:"jaw breaker", price: 1234),
      ItemList(category:"Other", name:"caramel", price: 1234),
      ItemList(category:"Other", name:"sour chew", price: 1234),
      ItemList(category:"Other", name:"gummi bear", price: 1234)]
  
      var filteredList : [ItemList] = []
  
      override func viewDidLoad()
      {
          super.viewDidLoad()
  
          self.title = "Item Search"
          self.tableView.delegate = self
          self.tableView.dataSource = self
  
          self.searchController = UISearchController(searchResultsController: nil)
          self.searchController!.searchResultsUpdater = self
          self.searchController!.hidesNavigationBarDuringPresentation = true
          self.searchController!.dimsBackgroundDuringPresentation = false
          self.searchController!.searchBar.searchBarStyle = .Minimal
          self.searchController!.searchBar.sizeToFit()
          self.tableView.tableHeaderView = self.searchController!.searchBar  
      }
  
      override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)
      {
          if (segue.identifier == "itemDetail")
          {
              let itemDetailViewController = segue.destinationViewController as UIViewController
              let selectedCell = sender as UITableViewCell
              itemDetailViewController.title = selectedCell.textLabel?.text
          }
      }
  
      override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -&gt; UITableViewCell
      {
          let cell = self.tableView.dequeueReusableCellWithIdentifier("Cell") as UITableViewCell
          var item : ItemList
  
          if self.searchController!.active
          {
              item = self.filteredList[indexPath.row]
          }
          else
          {
              item = self.itemList[indexPath.row]
          }
  
          cell.textLabel!.text = item.name
          return cell
  }
  
      override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -&gt; Int
      {
          if (self.searchController!.active)
          {
              return self.filteredList.count
          }
          else
          {
              return self.itemList.count
          }
      }
  }
  
  extension ItemSearchViewController: UISearchResultsUpdating
  {
      func updateSearchResultsForSearchController(searchController: UISearchController)
      {
          if (searchController.searchBar.text.isEmpty)
          {
              self.filteredList = self.itemList
          }
          else
          {
              let searchPredicate =
              {
                  (item: ItemList) -&gt; Bool in
                  item.name.rangeOfString(searchController.searchBar.text, options: .CaseInsensitiveSearch) != nil
              }
              self.filteredList = self.itemList.filter(searchPredicate)
          }
          self.tableView.reloadData()
      }
  }
  </code></pre>