how to set size of a scrollview to same size of a view - ios

Question

I have a view and inside the view there is a scrollview. I setup the scrollview programmatically. But for some reason the scrollview fits not perfectly in the view. The scrollview has the same frame as the view. But for some reason it is not working.
The white view is the view where the scrollview is in it.
The scrollview is the green view. I set the background color to green.
In the scrollview there is an image view.
My Code:
var scrollView: UIScrollView = {
let scrollView = UIScrollView()
scrollView.showsHorizontalScrollIndicator = false
scrollView.alwaysBounceVertical = false
scrollView.alwaysBounceHorizontal = false
scrollView.isPagingEnabled = true
return scrollView
}()
override func viewDidLoad() {
super.viewDidLoad()
scrollView.backgroundColor = .green
scrollView.frame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.size.width, height: contentView.frame.height) contentView.addSubview(scrollView)
scrollView.leftAnchor.constraint(equalTo: contentView.leftAnchor, constant: 0).isActive = true
scrollView.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 0).isActive = true
scrollView.rightAnchor.constraint(equalTo: contentView.rightAnchor, constant: 0).isActive = true
scrollView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: 0).isActive = true
}
var frame = CGRect.zero
func viewTutorial() {
for i in 0..<arrayOfTutorilImages.count {
frame.origin.x = scrollView.frame.size.width * CGFloat((i))
frame.size = scrollView.frame.size
let imageView = UIImageView(frame: frame)
imageView.image = UIImage(named: arrayOfTutorilImages[i])
imageView.contentMode = .scaleAspectFit
self.scrollView.addSubview(imageView)
}
scrollView.contentSize = CGSize(width: (scrollView.frame.size.width * CGFloat(arrayOfTutorilImages.count)), height: scrollView.frame.size.height)
scrollView.delegate = self
}
extension TutorialViewController: UIScrollViewDelegate {
func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
let pageNumber = scrollView.contentOffset.x / scrollView.frame.size.width
pageControl.currentPage = Int(pageNumber)
}
}
UPDATE:
I changed the frame and added constraints to the scrollview. Now it look like this. The images is not resizing (this image is the blue drawing)

Answer 1

I would recommend you to use constrains:
self.scrollView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
self.scrollView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
self.scrollView.topAnchor.constraint(equalTo: self.view.topAnchor),
self.scrollView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor)
You can create a helper method for this if you have like a UIView+Helpers, and use just one line.
extension UIView {
public func pinToEdges(of view: UIView,
topConstant: CGFloat = 0,
leadingConstant: CGFloat = 0,
bottomConstant: CGFloat = 0,
trailingConstant: CGFloat = 0) {
NSLayoutConstraint.activate([
self.topAnchor.constraint(equalTo: view.topAnchor, constant: topConstant),
self.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: leadingConstant),
self.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: bottomConstant),
self.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: trailingConstant),
])
}
}
And then use:
self.scrollView.pinToBounds(self.view)
And remember of course to set the translatesAutoresizingMaskIntoConstraints to false