I am trying to add a view to a UIScrollView
just using code, but the view doesn't appear in the UIScrollView
and I'm not sure why. When I added a button or label, they show up.
import UIKit
class profileViewController: UIViewController, UIScrollViewDelegate {
var label : UILabel = {
let label = UILabel()
label.text = "Profile"
label.textColor = UIColor.init(white: 0.80, alpha: 1)
label.font = UIFont.systemFont(ofSize: 40)
label.translatesAutoresizingMaskIntoConstraints = false
return label
}()
var scrollview : UIScrollView = {
let scrollview = UIScrollView()
scrollview.translatesAutoresizingMaskIntoConstraints = false
scrollview.backgroundColor = .clear
return scrollview
}()
var greyview : UIView = {
let view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false
view.backgroundColor = UIColor.init(white: 0.70, alpha: 1)
view.backgroundColor = UIColor.gray
return view
}()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
view.addSubview(label)
label.centerYAnchor.constraint(equalTo: view.safeAreaLayoutGuide.centerYAnchor).isActive = true
label.centerXAnchor.constraint(equalTo: view.safeAreaLayoutGuide.centerXAnchor).isActive = true
scrollview.delegate = self
view.addSubview(scrollview)
scrollview.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
scrollview.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
scrollview.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
scrollview.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
scrollview.contentSize = CGSize.init(width: view.frame.size.width, height: view.frame.size.height + 500)
scrollview.addSubview(greyview)
greyview.topAnchor.constraint(equalTo: scrollview.topAnchor).isActive = true
greyview.trailingAnchor.constraint(equalTo: scrollview.trailingAnchor).isActive = true
greyview.leadingAnchor.constraint(equalTo: scrollview.leadingAnchor).isActive = true
greyview.heightAnchor.constraint(equalToConstant: 100).isActive = true
}
}
This is probably because your greyview
doesnt have its bottomAnchor
. It needs the top and bottom anchors in order to work properly inside the scrollView:
scrollview.addSubview(greyview)
greyview.topAnchor.constraint(equalTo: scrollview.topAnchor).isActive = true
greyview.centerXAnchor.constraint(equalTo: scrollview.centerXAnchor).isActive = true
greyview.heightAnchor.constraint(equalToConstant: 100).isActive = true
greyview.widthAnchor.constraint(equalToConstant: 100).isActive = true
Add a widthAnchor, here I centered it in the scroll view but it is up to you to place it how you want it. Also if you add more items just make sure the bottom-most item has a bottomAnchor
attached to the scrollView bottomAnchor
or it will not scroll.
Update:
I don't know how you want your greyview
to look, but if you make the height taller than the contentSize
of the scrollView it will scroll, and make sure you have the bottomAnchor
:
scrollview.contentSize = CGSize.init(width: view.frame.size.width, height: view.frame.size.height)
scrollview.addSubview(greyview)
greyview.topAnchor.constraint(equalTo: scrollview.topAnchor).isActive = true
greyview.bottomAnchor.constraint(equalTo: scrollview.bottomAnchor).isActive = true
greyview.heightAnchor.constraint(equalTo: scrollview.heightAnchor, constant: 500).isActive = true
greyview.widthAnchor.constraint(equalTo: scrollview.widthAnchor).isActive = true
This makes the greyview
width equal to scrollview width, and height equal to scrollview height + 500 so that it scrolls.
this is one way:
self.scrollView = UIScrollView.init()
if let scrollView = self.scrollView {
scrollView.showsVerticalScrollIndicator = true
self.view.add(scrollView)
scrollView.translatesAutoresizingMaskIntoConstraints = false
self.addConstraint(UtilConstraint.addTopConstraint(from: scrollView, to: self, value: 0))
self.addConstraint(UtilConstraint.addBottomConstraint(from: scrollView, to: self, value: 0))
self.addConstraint(UtilConstraint.addLeftLeftConstraint(from: scrollView, to: self, value: 0))
self.addConstraint(UtilConstraint.addRightRightConstraint(from: scrollView, to: self, value: 0))
NSLayoutConstraint.activate(self.constraints)
greyview.translatesAutoresizingMaskIntoConstraints = false
scrollView.addSubview(greyview)
greyview.topAnchor.constraint(equalTo: scrollView.topAnchor).isActive = true
greyview.leftAnchor.constraint(equalTo: scrollView.leftAnchor).isActive = true
greyview.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor).isActive = true
greyview.widthAnchor.constraint(equalTo: scrollView.widthAnchor).isActive = true
}
Remember, your greyview
should have hight defined either statically or via. components inside.
though , what you were missing was defining a width. I have done it using widthAnchor. (assuming you need a vertical scroll)
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