UIScrollView with UIView Can't Select Any Subview Items - ios

Question

I currently have a UIViewController setup like this, and I'm unable to interact with the controls in the contentView.
I'm currently following this concept: https://developer.apple.com/library/archive/documentation/UserExperience/Conceptual/AutolayoutPG/WorkingwithScrollViews.html
class SimpleViewController: UIViewController {
override func viewDidLoad() {
let scrollView: UIScrollView = {
let newScrollView = UIScrollView()
newScrollView.translatesAutoresizingMaskIntoConstraints = false
let safeGuide = view.safeAreaLayoutGuide
self.view.addSubview(newScrollView)
newScrollView.topAnchor.constraint(equalTo: safeGuide.topAnchor).isActive = true
newScrollView.leadingAnchor.constraint(equalTo: safeGuide.leadingAnchor).isActive = true
newScrollView.trailingAnchor.constraint(equalTo: safeGuide.trailingAnchor).isActive = true
newScrollView.bottomAnchor.constraint(equalTo: safeGuide.bottomAnchor).isActive = true
return newScrollView
}()
let contentView: UIView = {
let newView = UIView()
newView.translatesAutoresizingMaskIntoConstraints = false
scrollView.addSubview(newView)
newView.topAnchor.constraint(equalTo: scrollView.topAnchor, constant: 0).isActive = true
newView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor, constant: 0).isActive = true
newView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor, constant: 0).isActive = true
newView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true
return newView
}()
let createBtn: UIButton = {
let btn = UIButton()
btn.setTitle("Create", for: UIControl.State.normal)
btn.backgroundColor = .orange;
btn.translatesAutoresizingMaskIntoConstraints = false;
contentView.addSubview(btn)
btn.layer.cornerRadius = 6.0;
btn.contentEdgeInsets = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10);
btn.topAnchor.constraint(equalTo: contentView.topAnchor).isActive = true
btn.leadingAnchor.constraint(equalTo: contentView.leadingAnchor).isActive = true
btn.widthAnchor.constraint(equalToConstant: 100).isActive = true
return btn
}()
let cancelBtn: UIButton = {
let btn = UIButton()
btn.setTitle("Cancel", for: UIControl.State.normal)
btn.backgroundColor = .red;
btn.translatesAutoresizingMaskIntoConstraints = false;
contentView.addSubview(btn)
btn.layer.cornerRadius = 6.0;
btn.contentEdgeInsets = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10);
btn.topAnchor.constraint(equalTo: contentView.topAnchor).isActive = true
btn.leadingAnchor.constraint(equalTo: createBtn.trailingAnchor).isActive = true
btn.widthAnchor.constraint(equalToConstant: 100).isActive = true
btn.addTarget(self, action: #selector(self.cancelCreateOrder), for: .touchUpInside);
return btn
}()
}
}
If I were to add the buttons directly to the scrollView, then I can interact with them. However, with them in the contentView, it's not registering any clicks.

Answer 1

Add 2 constraints
// contentView should tell scrollView it's width ( setting the leading and trailing isn't enough what matters the width to be inside the scrollView which is still un-known even after hooking the leading & trailing )
newView.widthAnchor.constraint(equalTo: view.widthAnchor, constant: 0).isActive = true
And
// contentView should tell scrollView it's height by top & bottom constraints hooking
btn.bottomAnchor.constraint(equalTo: contentView.bottomAnchor).isActive = true