Adding a vertical UIScrollView programmatically - ios

Question

I'm not making progress on this problem for a while now.
I'm trying to add a vertical scroll view to my app with a contentView (UIView). I added the contentView as a subview of the scrollView & added the scrollView as a subview of the main view. After that, I wasn't able to scroll and buttons + the searchbar weren't working anymore. It just felt like the app was frozen.
What I've done so far is the following:
Creating the scroll- and contentView directly in the class
let scrollView:UIScrollView = UIScrollView()
let contentView:UIView = UIView()
Setting up the scrollView
func setupScrollView() {
scrollView.translatesAutoresizingMaskIntoConstraints = false
contentView.translatesAutoresizingMaskIntoConstraints = false
scrollView.contentSize = CGSize(width: self.view.frame.width, height: self.view.frame.height)
// Add scroll view to main view
self.view.addSubview(scrollView)
// Add content to scrollview
scrollView.addSubview(contentView)
// Constraints
scrollView.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
scrollView.widthAnchor.constraint(equalTo: self.view.widthAnchor).isActive = true
scrollView.topAnchor.constraint(equalTo: self.view.topAnchor).isActive = true
contentView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor).isActive = true
contentView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor).isActive = true
scrollView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor).isActive = true
contentView.centerXAnchor.constraint(equalTo: scrollView.centerXAnchor).isActive = true
contentView.widthAnchor.constraint(equalTo: scrollView.widthAnchor).isActive = true
contentView.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor).isActive = true
contentView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor).isActive = true
contentView.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
contentView.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true
}
Adding several elements as subview to the contentView
// Add search bar to scroll content view
contentView.addSubview(searchBar)
The full code is available on my github repo
I looked through several similar problems and tutorials but somehow can't figure out what's wrong here.