How to set scrollview height programmatically

Question

How can I set the scrollview height programmatically in Xcode 9 with Swift 4? I've set a constraint for the scrollview height and added that as an outlet. But when I change the outlet constant value programmatically it doesn't change the height.

Example:

@IBOutlet weak var scrollview_height: NSLayoutConstraint!

override func viewDidLoad() {
     super.viewDidLoad()
     self.scrollview_height.constant = 245
}

Answer 1

The height of the ScrollView should be given by it's content and not for you to change manually. At best if you want to do something like that, you have a view inside the scrollView and change the size of that view instead.

Step-by-step:

• Add a ScrollView to your view. Set it's constraints (no height or width)
• Add a View inside the ScrollView and set it's constraints. Additionally for a vertical scroll you might want to set it's width equal to the SuperView and ensure it has a height.
• Create an IBOutlet for the height of the view
• update the constant value of the constraint in code
• If it does not update as expected, run a layoutIfNeeded on your superview after updates

Answer 2

You have to increase the content Size of your scrollView instead of increasing the frame of scrollView.

self.scrollview.contentSize = CGSize(width: screenWidth, height: yourDesiredHeight) 

the scrollable contentSize of scrollView will change According to it.