UIButton not showing when UIScrollView showing on ViewController - ios

Question

I have a UIViewController that is attached to a class, Swift code below. The code basically adds to the View Controller a UIScrollView with an image.
I am wanting to add a UIButton to the ViewController which I could do through code, however in this case, I want to add the UIButton to the ViewController using the Storyboard.
When I add a UIButton and then run my project, the UIButton is not visible, only the UIScrollView is visible.
Question:
What is going on, why is the UIButton not visible? How can I add a UIButton (to the Storyboard) and ensure that it is visible and in front of the UIScrollView (that is created programatically) when I run the project?
class ScrollViewController: UIViewController, UIScrollViewDelegate {
var scrollView: UIScrollView!
var imageView: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
imageView = UIImageView(image: UIImage(named: "image.png"))
scrollView = UIScrollView(frame: view.bounds)
scrollView.backgroundColor = UIColor.blackColor()
scrollView.contentSize = imageView.bounds.size
scrollView.autoresizingMask = [UIViewAutoresizing.FlexibleWidth, UIViewAutoresizing.FlexibleHeight]
scrollView.contentOffset = CGPoint(x: 1000, y: 450)
scrollView.addSubview(imageView)
view.addSubview(scrollView)
scrollView.delegate = self
setZoomScale()
setupGestureRecognizer()
}
func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
return imageView
}
override func viewWillLayoutSubviews() {
setZoomScale()
}
func setZoomScale() {
let imageViewSize = imageView.bounds.size
let scrollViewSize = scrollView.bounds.size
let widthScale = scrollViewSize.width / imageViewSize.width
let heightScale = scrollViewSize.height / imageViewSize.height
scrollView.minimumZoomScale = min(widthScale, heightScale)
scrollView.zoomScale = 1.0
}
func scrollViewDidZoom(scrollView: UIScrollView) {
let imageViewSize = imageView.frame.size
let scrollViewSize = scrollView.bounds.size
let verticalPadding = imageViewSize.height < scrollViewSize.height ? (scrollViewSize.height - imageViewSize.height) / 2 : 0
let horizontalPadding = imageViewSize.width < scrollViewSize.width ? (scrollViewSize.width - imageViewSize.width) / 2 : 0
scrollView.contentInset = UIEdgeInsets(top: verticalPadding, left: horizontalPadding, bottom: verticalPadding, right: horizontalPadding)
}
func setupGestureRecognizer() {
let doubleTap = UITapGestureRecognizer(target: self, action: "handleDoubleTap:")
doubleTap.numberOfTapsRequired = 2
scrollView.addGestureRecognizer(doubleTap)
}
func handleDoubleTap(recognizer: UITapGestureRecognizer) {
if (scrollView.zoomScale > scrollView.minimumZoomScale) {
scrollView.setZoomScale(scrollView.minimumZoomScale, animated: true)
} else {
scrollView.setZoomScale(scrollView.maximumZoomScale, animated: true)
}
}
}

Answer 1

Your scrollview is blocking the UIButton on z axis, please use
- (void)insertSubview:(UIView *)view atIndex:(NSInteger)index;
to insert scrollview below UIButton
Swift:
func insertSubview(view: UIView, atIndex index: Int) {
}
Answer:
Instead of this line view.addSubview(scrollView), you need to do self.view.insertSubview(scrollView, atIndex: 0) and make sure UIButton is above the scrollView.

Answer 2

You have to write:
self.view.insertSubview(scrollview, belowSubview: button)