Resizeable then scrollable UITextView like Telegram - ios

Question

I want to create UITextView that can resize and scroll at the same time like the ones on Telegram , Instagram or Whats App that allow UITextView to grow up to or 8 lines then you can scroll if you add more text to it I was able to make the UITextView grow to 5 line but if they are more text I can not see since the isScroll property is disabled
my UITextView is inside UIView with two button on the left and right and I would prefer to do it through constrain if that's possible if not through code is fine too

Answer 1

Sagar's answer is great, but I want to enhance it a bit and add some animation to it:
the steps you need
get an outlet to your textView
add a height constraint and get an outlet to it
implement textViewDidChange delegate method of the textView
in textViewDidChange
calculate new height using textView.sizeThatFits(size)
set the height constraint constant to new height
[optional] animate the constraint change to be more user friendly
here is an example
class ViewController: UIViewController {
#IBOutlet weak var textView: UITextView!
#IBOutlet weak var textViewHeightConstraint: NSLayoutConstraint!
let maxTextHeight:CGFloat = 200
let minTextHeight:CGFloat = 50
let animationDuration:Double = 0.3
override func viewDidLoad() {
super.viewDidLoad()
textView.delegate = self
resizeTextViewToFitText()
}
func resizeTextViewToFitText() {
let size = CGSize(width: textView.frame.width, height: .infinity)
let expectedSize = textView.sizeThatFits(size)
self.textViewHeightConstraint.constant = max(min(expectedSize.height, self.maxTextHeight), self.minTextHeight)
self.textView.isScrollEnabled = expectedSize.height > self.maxTextHeight
UIView.animate(withDuration: animationDuration) {
self.view.layoutIfNeeded()
}
}
}
extension ViewController: UITextViewDelegate {
func textViewDidChange(_ textView: UITextView) {
resizeTextViewToFitText()
}
}

Answer 2

You can achieve your expected outcome by following steps:
Assign a textView delegate to your controller
Default disable textView scrolling
On textViewDidChange delegate method measure text height according textView frame
Assign appropriate height to textview & enable scroll if content is exceeded (Up to max height in your case 8 line)
Here below I am attaching code snippet, which may help you:
let commentViewMinHeight: CGFloat = 45.0
let commentViewMaxHeight: CGFloat = 120.0 //In your case it should be 8 lines
func textViewDidChange(_ textView: UITextView) {
//Calculate text height
let size = textView.sizeThatFits(CGSize(width: textView.frame.size.width, height: CGFloat.greatestFiniteMagnitude))
textViewHeightConstraint.constant = size.height.clamped(to: commentViewMinHeight...commentViewMaxHeight)
if textView.contentSize.height < commentViewMaxHeight {
textView.setContentOffset(CGPoint.zero, animated: false)
if textView.isScrollEnabled {
textView.isScrollEnabled = false
}
} else {
if !textView.isScrollEnabled {
textView.isScrollEnabled = true
}
}
}
extension Comparable {
func clamped(to limits: ClosedRange<Self>) -> Self {
return min(max(self, limits.lowerBound), limits.upperBound)
}
}