UIBarButtonItem不在水平滚动下显示

Question

我跟着this tutorial，特别是在“使用UIScrollView进行分页”部分下创建水平滚动。目前，我已将其设置为使图像覆盖整个画面/屏幕。

我正在尝试在导航栏上添加一个简单的UIBarButtonItem（使用Storyboard），以尝试构建一个滑出式菜单。但是，该按钮不会显示。此外，即使我尝试self.navigationController?.navigationBarHidden = false，导航栏也不会显示。

我当前的视图控制器是这样编写的。

class HomeViewController: UIViewController, UIScrollViewDelegate {
    @IBOutlet weak var pagedScrollView: UIScrollView!
    @IBOutlet weak var pageControl: UIPageControl!
    @IBOutlet weak var hamburger: UIBarButtonItem! // the button

    var pageImages: [UIImage] = []
    var pageViews: [UIImageView?] = []

    override func viewDidLoad() {
        super.viewDidLoad()

        self.navigationController?.toolbarHidden = false

        hamburger.target = self.revealViewController()
        hamburger.action = Selector("revealToggle:")
    }

    override func prefersStatusBarHidden() -> Bool {
        return true
    }

    override func viewDidAppear(animated: Bool) {

        let weatherData = WeatherDataLibrary().library
        pageImages = [
            UIImage(named: weatherData[0]["image"] as! String!)!,
            UIImage(named: weatherData[1]["image"] as! String!)!,
            UIImage(named: weatherData[2]["image"] as! String!)!,
            UIImage(named: weatherData[3]["image"] as! String!)!,
            UIImage(named: weatherData[4]["image"] as! String!)!,
            UIImage(named: weatherData[5]["image"] as! String!)!,
        ]

        let pageCount = weatherData.count

        pageControl.currentPage = 0
        pageControl.numberOfPages = pageCount

        for _ in 0..<pageCount {
            pageViews.append(nil)
        }

        let pagesScrollViewSize = pagedScrollView.frame.size
        pagedScrollView.contentSize = CGSize(width: pagesScrollViewSize.width * CGFloat(pageImages.count),
            height: pagesScrollViewSize.height)

        loadVisiblePages()
    }

    func loadPage(page: Int) {
        if page < 0 || page >= pageImages.count {
            // If it's outside the range of what you have to display, then do nothing
            return
        }

        // 1
        if let pageView = pageViews[page] {
            // Do nothing. The view is already loaded.
        } else {
            // 2
            var frame = pagedScrollView.bounds
            frame.origin.x = frame.size.width * CGFloat(page)
            frame.origin.y = 0.0

            // 3
            let newPageView = UIImageView(image: pageImages[page])

            newPageView.contentMode = .ScaleToFill
            newPageView.frame = frame
            pagedScrollView.addSubview(newPageView)

            // 4
            pageViews[page] = newPageView

        }
    }

    func purgePage(page: Int) {
        if page < 0 || page >= pageImages.count {
            // If it's outside the range of what you have to display, then do nothing
            return
        }

        // Remove a page from the scroll view and reset the container array
        if let pageView = pageViews[page] {
            pageView.removeFromSuperview()
            pageViews[page] = nil
        }
    }

    func loadVisiblePages() {
        // First, determine which page is currently visible
        let pageWidth = pagedScrollView.frame.size.width
        let numberOfImages = pageImages.count
        let page = Int(floor((pagedScrollView.contentOffset.x * CGFloat(numberOfImages) + pageWidth) / (pageWidth * CGFloat(numberOfImages))))

        // Update the page control
        pageControl.currentPage = page

        // Work out which pages you want to load
        let firstPage = 0
        let lastPage = numberOfImages

        // Purge anything before the first page
        for var index = 0; index < firstPage; ++index {
            purgePage(index)
        }

        // Load pages in our range
        for index in firstPage...lastPage {
            loadPage(index)
        }

        // Purge anything after the last page
        for var index = lastPage+1; index < pageImages.count; ++index {
            purgePage(index)
        }
    }

    func scrollViewDidScroll(pagedScrollView: UIScrollView!) {
        // Load the pages that are now on screen
        loadVisiblePages()
    }