Ios/swift/ナビゲーションバー/右上にボタンを追加

アイコンボタンの場合

   override func viewDidLoad() {
       super.viewDidLoad()
       let rightBookmarkBarButtonItem: UIBarButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Bookmarks, target: self, action: #selector(self.bookmarkButtonTapped))
       self.navigationItem.setRightBarButtonItems([rightBookmarkBarButtonItem], animated: true)
   }
   func bookmarkButtonTapped() {
   }

テキストボタンの場合

       let rightBookmarkBarButtonItem = UIBarButtonItem(title: "☆", style: .Plain, target: nil, action: nil)