Swift 3 UIScrollview not asking zooming - ios

Question

This is driving me nuts!
I'm basing my UIScrollView on http://koreyhinton.com/blog/uiscrollview-crud.html to make it programatic, so have set up a container view inside my scrollview. But it pans, but won't zoom.
class BinaryTreeViewController: UIViewController, UIScrollViewDelegate {
var scrollView: UIScrollView!
var containerView : UIView!
override func viewDidLoad() {
super.viewDidLoad()
let width:CGFloat = self.view.bounds.width
let height:CGFloat = self.view.bounds.height
scrollView = UIScrollView()
scrollView.delegate = self
scrollView.minimumZoomScale = 0.5
scrollView.maximumZoomScale = 2.0
scrollView.contentSize = CGSize(width: width*2, height: 2000)
scrollView.backgroundColor = .red
containerView = UIView()
scrollView.addSubview(containerView)
view.addSubview(scrollView)
containerView.isUserInteractionEnabled = true
scrollView.isUserInteractionEnabled = true
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
scrollView.frame = view.bounds
containerView.frame = CGRect(x: 0, y: 0, width: scrollView.contentSize.width, height: scrollView.contentSize.height)
}
override func viewWillLayoutSubviews() {
//I create a view called "theView"
containerView.addSubview(theView)
}
The following functions do not fire at any point
func update(zoomScale: CGFloat, offSet: CGPoint) {
scrollView.zoomScale = zoomScale
}
func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
return containerView
}
func scrollViewDidZoom(_ scrollView: UIScrollView) {
NSLog("scroll")
}

Answer 1

You really don't need to do so much code for that purpose.
You can set up all you need for scrollView in storyboard, and you only need outlet for the view you wish to zoom.
Set up a controller, add scrollview, connect delegate property to view controller, add zooming view as subview in IB.
In the class, conform controller to UIScrollViewDelegate, and use viewForZooming, a scrollView delegate method.
class ViewController: UIViewController, UIScrollViewDelegate {
#IBOutlet weak var zoomer: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func viewForZooming(in scrollView: UIScrollView) -> UIView? {
return zoomer
}
}
P.S. Use newer resources for learning, Ray Wenderlich, AppCoda, etc - its a big web full of good sources, and Swift is in constant change.