Estimating size of UICollectionView cell for some text - swift

Question

So I'm creating a messaging type app, which consists of some blocks of UITextView containing varying lengths of text and these reside in a "bubble" UIView.
let textView: UITextView = {
let text = UITextView()
text.text = "SAMPLE"
text.translatesAutoresizingMaskIntoConstraints = false
text.backgroundColor = .clear
text.textColor = .white
return text
}()
let bubbleView: UIView = {
let view = UIView()
view.backgroundColor = UIColor(r: 0, g: 137, b: 247)
view.layer.cornerRadius = 14
view.layer.masksToBounds = true
view.translatesAutoresizingMaskIntoConstraints = false
return view
}()
var bubbleWidthAnchor: NSLayoutConstraint?
bubbleView.rightAnchor.constraint(equalTo: self.rightAnchor, constant: -8).isActive = true
bubbleView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
bubbleWidthAnchor = bubbleView.widthAnchor.constraint(equalToConstant: 250)
bubbleWidthAnchor?.isActive = true
bubbleView.heightAnchor.constraint(equalTo: self.heightAnchor).isActive = true
textView.leftAnchor.constraint(equalTo: bubbleView.leftAnchor, constant: 8).isActive = true
textView.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
textView.rightAnchor.constraint(equalTo: bubbleView.rightAnchor).isActive = true
textView.heightAnchor.constraint(equalTo: self.heightAnchor).isActive = true
To set the height of the cell I am using a custom function which is supposed to not working properly.
Custom function:
private func estimatedFrameForText(text: String) -> CGRect {
let size = CGSize(width: 250, height: 250)
let options = NSStringDrawingOptions.usesFontLeading.union(.usesLineFragmentOrigin)
return NSString(string: text).boundingRect(with: size, options: options, attributes: [NSFontAttributeName: UIFont.systemFont(ofSize: 16)], context: nil)
}
Which I call in the sizeForItemAt function for UICollectionView:
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
var height: CGFloat = 80 //Arbitrary number
if let text = messages[indexPath.item].text {
height = estimatedFrameForText(text: text).height + 8
}
return CGSize(width: view.frame.width, height: height)
}
The simple problem I am having is... it does not working great:
Example
Any idea where I am going wrong, or a better solution to getting the estimated size I need for the cell, depending on the text?

Answer 1

As it turns out, all that I was missing was to set the text size in the textView.
Putting text.font = UIFont.systemFont(ofSize: 16) in was required because the function to get the estimated size has:
attributes: [NSFontAttributeName: UIFont.systemFont(ofSize: 16)
So you have to define both to be the same.

Answer 2

Swift 4.2 updated answer is to handle height and width of uicollectionviewCell on the basis of uilabel
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize
{
let size = (self.FILTERTitles[indexPath.row] as NSString).size(withAttributes: [NSAttributedString.Key.font: UIFont.systemFont(ofSize: 14.0)])
return CGSize(width: size.width + 38.0, height: size.height + 25.0)
}