I'm running across this issue which I can't seem to find the answer to online. Basically what I'm trying to do is programmatically create a UIToolbar with some UIBarButtonItems. 
What I've done (as detailed below) is create the UIToolbar and then set the items of the UIToolbar to an array holding all the UIBarButtonItems I want.
Unfortunately, though the UIToolbar shows up, the UIBarButtonItems have yet to show themselves
Any suggestions or explanations as to why this is happening is much appreciated!
class DrawViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        //create bar buttons
        let deleteBarButton = UIBarButtonItem(image: UIImage(named: "greyDelete"), style: .Plain, target: self, action: "deleteView:")
        let eraseBarButton = UIBarButtonItem(image: UIImage(named: "greyErase"), style: .Plain, target: self, action: "erase:")
        let resizeBarButton = UIBarButtonItem(image: UIImage(named: "greyResize"), style: .Plain, target: self, action: "resize:")
        let viewBarButton = UIBarButtonItem(image: UIImage(named: "greyView"), style: .Plain, target: self, action: "view:")
        let colorBarButton = UIBarButtonItem(image: UIImage(named: "greyColor"), style: .Plain, target: self, action: "color:")
        let drawBarButton = UIBarButtonItem(image: UIImage(named: "greyDraw"), style: .Plain, target: self, action: "draw:")
        let flexibleSpace = UIBarButtonItem(barButtonSystemItem: .FlexibleSpace, target: self, action: nil)
        //set up toolbar
        let toolbarItems = [deleteBarButton, flexibleSpace, eraseBarButton, 
                            flexibleSpace, resizeBarButton, flexibleSpace, 
                            viewBarButton, flexibleSpace, colorBarButton, 
                            flexibleSpace, drawBarButton]
        let toolbar = UIToolbar(frame: CGRectMake(0, view.bounds.height*0.93, view.bounds.width, view.bounds.height*0.7))
        toolbar.barTintColor = UIColor(patternImage: UIImage(named: "blueToolbar")!)
        toolbar.setItems(toolbarItems, animated: true)
        self.view.addSubview(toolbar)
    }