Swift textview growing direction

Question

so i have a textview inside a uiview. And my question is how to make my textivew grow in up direction when textview goes to the next line as well as my uiview.

var textheightcontraint : NSLayoutConstraint!
var viewheightconstraint : NSLayoutConstraint!


func setup4(){
    view.addSubview(colorview)
    colorview.topAnchor.constraint(equalTo: customtableview.bottomAnchor).isActive = true
    colorview.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
    colorview.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
    viewheightconstraint = colorview.heightAnchor.constraint(equalToConstant: 44)
    viewheightconstraint.isActive = true
    colorview.backgroundColor = UIColor.lightGray

    colorview.addSubview(customtextview2)
    customtextview2.backgroundColor = .white
    customtextview2.leftAnchor.constraint(equalTo: colorview.leftAnchor).isActive = true
    customtextview2.rightAnchor.constraint(equalTo: colorview.rightAnchor, constant: -20).isActive = true
    customtextview2.bottomAnchor.constraint(equalTo: colorview.bottomAnchor).isActive = true
    textheightcontraint = customtextview2.heightAnchor.constraint(equalToConstant: 39)
    textheightcontraint.isActive = true
    customtextview2.delegate = self

}
func setuptextview(){
    let fixedWidth = customtextview2.frame.size.width
    let newSize = customtextview2.sizeThatFits(CGSize(width: fixedWidth, height: CGFloat.greatestFiniteMagnitude))
    self.textheightcontraint.constant = newSize.height
    self.viewheightconstraint.constant = newSize.height
    self.view.layoutIfNeeded()
}
func textViewDidChange(_ textView: UITextView) {
    setuptextview()
}

Answer 1

If I understand your question, you want the text view (and the view it's contained in) to keep its bottom at the same position, and expand upward as you type?

To do that, disable scrolling in the text view, and set up your constraints so the bottom of the containing view is constrained to a y-position:

//
//  ViewController.swift
//
//  Created by Don Mag on 8/9/18.
//

import UIKit

class ViewController: UIViewController {

    var theContainingView: UIView = {
        let v = UIView()
        v.translatesAutoresizingMaskIntoConstraints = false
        return v
    }()

    var theTextView: UITextView = {
        let v = UITextView()
        v.translatesAutoresizingMaskIntoConstraints = false
        return v
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        self.view.backgroundColor = .yellow

        theContainingView.backgroundColor = .cyan

        theContainingView.addSubview(theTextView)

        view.addSubview(theContainingView)

        NSLayoutConstraint.activate([

            theTextView.topAnchor.constraint(equalTo: theContainingView.topAnchor, constant: 8.0),
            theTextView.bottomAnchor.constraint(equalTo: theContainingView.bottomAnchor, constant: -8.0),
            theTextView.leadingAnchor.constraint(equalTo: theContainingView.leadingAnchor, constant: 8.0),
            theTextView.trailingAnchor.constraint(equalTo: theContainingView.trailingAnchor, constant: -8.0),

            theContainingView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 40.0),
            theContainingView.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -40.0),

            // Constrain the Bottom of the containing view. As the textView grows (or shrinks) with input,
            // the TOP of the view will move up or down
            theContainingView.bottomAnchor.constraint(equalTo: view.topAnchor, constant: 300.0),

            ])

        theTextView.isScrollEnabled = false
        theTextView.text = "This is the starting text."

    }

}

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