Make UITextView height dynamic, issue with constraint multiplier - ios

Question

I have a UICollectionView which contains five cells. In there, I have a UIImageView, two UILabels and a UITextView. I want to change the height of the textview based on the text it contains, so afterwards I can set the height of the entire cell based on the height of the UITextView and the labels above them. Let me demonstrate with a screenshot.
So, as you can tell, the red background shows the height of the UITextView is not right. I set up the UITextView like this:
let commentTextView: UITextView = {
let textView = UITextView()
textView.translatesAutoresizingMaskIntoConstraints = false
textView.text = "This is just some text to act as a description"
textView.textContainerInset = UIEdgeInsets(top: 0, left: -4, bottom: 0, right: 0)
textView.font = UIFont.systemFont(ofSize: 16.0)
textView.textColor = UIColor.darkGray
textView.isEditable = false
textView.isSelectable = false
textView.backgroundColor = UIColor.red
textView.frame.size.width = (UIScreen.main.bounds.width - 16 - 16 - 60 - 8)
let numberOfLines = (textView.contentSize.height / textView.font!.lineHeight)
var textViewHeight = (textView.font?.lineHeight)! * floor(numberOfLines)
textView.frame.size.height = textViewHeight
return textView
}()
This does not create the wrong height, I think. I think the problem can be found in my constraints, which has a height constraint (if I delete it, the UITextView disappears). If I change the multiplier (currently set at 0.3), I have different heights, but I want this to be dynamically. So in my opinion, I would need to set a dynamic variable inside the multiplier, but I have no idea how to compose it. Could anyone help? Here are my constraints:
// top constraints
addConstraints([NSLayoutConstraint(item: commentTextView, attribute: .top, relatedBy: .equal, toItem: workoutLabel, attribute: .bottom, multiplier: 1, constant: 2)])
// left constraint
addConstraints([NSLayoutConstraint(item: commentTextView, attribute: .left, relatedBy: .equal, toItem: profilePictureImageView, attribute: .right, multiplier: 1, constant: 16)])
// right constraint
addConstraints([NSLayoutConstraint(item: commentTextView, attribute: .right, relatedBy: .equal, toItem: self.commentTextView.superview, attribute: .right, multiplier: 1, constant: -16)])
// height constraint
addConstraints([NSLayoutConstraint(item: commentTextView, attribute: .height, relatedBy: .equal, toItem: self, attribute: .height, multiplier: 0.3, constant: 1)])
Cheers guys!

Answer 1

You could consider another way about dynamic height of UITextView. It's known about intrinsic content size. You could implement dynamic height with that tech.

Answer 2

Originally answered here.
Don't change or give any frame to your UITextView. Just give it leading, trailing, top & bottom constraints. Then if your cell is capable of having automatic size then you don't need to calculate anything for your text view.
When using Auto-Layout for dynamically sizing cells, you don't really need to implement sizeThatFits(...). If the constraints are setup correctly, then you only need to disable the scrolling of the UITextView.
From code:
yourTextView.scrollEnabled = false
From IB:
Select your Text View and open Attributes inspector, then
Now if you are facing problems with making your cell to have dynamic size then please look at this answer.

Answer 3

As mentioned yesterday, I had the textview adapt its size based on the answer of #nayem - thank you!
However, I faced another problem with making the cell height dynamic. I have looked into different solutions, got nothing to work, except when I calculate the height myself and set this as the height to be used. This works on all devices in Simulator, just wondering if this is the right approach. Code below, constraints are set on top, left and right.
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let dummyText = "Just a long text to see what will happen to the cell. Will it adapt or not? Let's find out!"
let rectWidth = view.frame.width - 32 - 60 - 16
let rect = NSString(string: dummyText).boundingRect(with:CGSize(width: rectWidth, height: 1000), options: NSStringDrawingOptions.usesFontLeading.union(NSStringDrawingOptions.usesLineFragmentOrigin), attributes: [NSAttributedStringKey.font: UIFont.systemFont(ofSize: 16)], context: nil)
let variableHeight = 16 + 20 + 2 + 20 + 2 + 16 + rect.height
return CGSize(width: view.frame.width, height: variableHeight)
}
Is this the best way to do this? Will this cause problems later on?