UITextView boundingRect not working properly

Question

For UITextField, I am currently using the following extension to compute a bounding box for a given row.

func widthHeight(font: UIFont) -> CGRect {
    let constraintRect = CGSize(width: 200, height: 1000)
    let boundingBox = self.boundingRect(with: constraintRect, options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)
    return boundingBox
}

Width for constraintRectis the maximum width that I want to allow for the window.

I set the values ​​and cells as follows:

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    if let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuse, for: indexPath) as? ChatCollectionViewCell {

        let text = self.chatLog[indexPath.row].text
        cell.chatTextView.text = text

        cell.chatViewWidth = (text?.widthHeight(font: UIFont.systemFont(ofSize: 16)).width)!

        return cell
    }
    return UICollectionViewCell()
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    if let text = self.chatLog[indexPath.row].text {            
        let box = text.widthHeight(font: UIFont.systemFont(ofSize: 16))
        return CGSize(width: view.frame.width, height: box.height + 10)
    }
    return CGSize(width: self.view.frame.width, height: 60)
}

When this code works, I get massively calculated cell sizes:

As you can see, presentation frames are very confusing. The first line is "Heya", the second line is "How life goes," and the third line is "I'm a stapler, you're a textbook." Some cells are too narrow, some cells are too wide.

Here is another additional code for my custom ViewCell:

override init(frame: CGRect) {
    super.init(frame: frame)

    setupViews()
}

override func layoutSubviews() {

    chatView.frame = CGRect(x: 0, y: 0, width: chatViewWidth, height: frame.height)
    chatTextView.frame = CGRect(x: chatView.frame.origin.x + 10, y: 0, width: chatView.frame.width - 20, height: chatView.frame.height)
}

func setupViews() {    

    if isTextFromCurrentUser {
        chatTextView.frame = CGRect(x: 10, y: 0, width: frame.width - 140, height: frame.height)
        chatTextView.backgroundColor = .white
    } else {
        chatTextView.frame = CGRect(x: frame.width - 150, y: 0, width: frame.width - 140, height: frame.height)
        chatTextView.backgroundColor = .blue
    }

    chatTextView.font = UIFont.systemFont(ofSize: 16)
    chatTextView.layer.cornerRadius = 9
    chatTextView.clipsToBounds = true
    chatTextView.autoresizingMask = UIViewAutoresizing.flexibleHeight
    chatTextView.isScrollEnabled = false

    contentView.addSubview(chatView)
    contentView.addSubview(chatTextView)
}

Answer 1

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func widthHeight(font: UIFont) -> CGRect {
    let constraintRect = CGSize(width: 200, height: CGFloat.greatestFiniteMagnitude)
    let boundingBox = self.boundingRect(with: constraintRect, options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)
    return boundingBox
}

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func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
       let textView = UITextView(frame: CGRect.zero)
       //set textView property here 
       textView.text = self.chatLog[indexPath.row].text
       let size = textView.sizeThatFits(CGSize(width: textView.bounds.width, height: CGFloat.greatestFiniteMagnitude))
       return size;
}