Swift textview growing direction - ios

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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