How to change the TextView height dynamicly to a threshold and then allow scrolling?

Question

I have a TextView that has a constraint of min height of 33. The scroll is disabled from the storyboard. The TextView should increase in height based on the content until it

Answer 1

Maybe the code below is a little better.

import UIKit

let width = UIScreen.mainScreen().bounds.width

class ViewController: UIViewController, UITextViewDelegate {

    var messageTextView: UITextView!
    let messageTextViewMaxHeight: CGFloat = 100

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.redColor()
        messageTextView = UITextView(frame: CGRectMake(0, 200 - 33, width, 33))
        messageTextView.backgroundColor = UIColor.whiteColor()
        view.addSubview(messageTextView)
        self.messageTextView.delegate = self
    }

    //
    let bottomY: CGFloat = 200

    func textView(textView: UITextView, shouldChangeTextInRange range: NSRange, replacementText text: String) -> Bool {
        if text == "\n"{
            let formerRect = textView.frame
            let contentSize = textView.contentSize
            if contentSize.height < formerRect.height{
                //
            }
            else{
                if contentSize.height >= messageTextViewMaxHeight{
                    //
                }
                else{
                    textView.frame = CGRectMake(formerRect.origin.x, bottomY - contentSize.height, width, contentSize.height)
                }
            }
        }
        return true
    }

}