Swift 4 - How do I test for TextView content did change? - uitextview

Question

Swift 4, iOS 11 - I have a UITextView that is pre-populated with text but I want users to be able to save any changes they make to the content there. I also have a Save button in the navigation bar and I would like to disable it until the user actually changes the text in the TextView.
I know how to test for empty but I don't know how to test for when the text has been edited. How do I modify the following to test for changes to the content of TextView?
#IBAction func textEditingChanged(_ sender: UITextView) {
updateSaveButtonState()
}
func updateSaveButtonState() {
let descriptionText = descriptionTextView.text ?? ""
saveButton.isEnabled = !descriptionText.isEmpty
}

Answer 1

We'll to use it a dynamic way and not only in single place, i tried to make it easier to implement around the whole app, subclassing the UITextView is one of the only ways we got here #holex has suggested isEdited boolean flag and it gave me an idea, Thanks to that.
Here is the steps to implement it:
First of all set the defaultText of the textView and set the target of the method that will be called when the textView will be edited, so you can customize what ever you want.
#IBOutlet weak var saveButton: UIBarButtonItem!
#IBOutlet weak var textView: SBTextView!{
didSet{
textView.defaultText = "Hello"
textView.setTarget = (selector:#selector(self.updateSaveButtonState),target:self)
}
}
Lets say you'll setup the saveButton in viewDidLoad:
override func viewDidLoad() {
super.viewDidLoad()
// setup save button action
saveButton.action = #selector(saveAction(_:))
saveButton.target = self
self.updateSaveButtonState()
}
And last is your save action and the selector to update the view using isEdited flag.
//MARK:- Actions
#objc private func updateSaveButtonState(){
// has not been changed keep save button disabled
if self.textView.isEdited == false{
self.saveButton.isEnabled = false
self.saveButton.tintColor = .gray
}else {
// text has been changed enable save button
self.saveButton.isEnabled = true
self.saveButton.tintColor = nil // will reset the color to default
}
}
#objc private func saveAction(_ saveButton:UIBarButtonItem){
self.textView.updateDefaultText()
}
TextView Custom Class:
//
// SBTextView.swift
//
//
// Created by Saad Albasha on 11/17/17.
// Copyright © 2017 AaoIi. All rights reserved.
//
import UIKit
class SBTextView: UITextView,UITextViewDelegate {
var isEdited = false
private var selector : Selector?
private var target : UIViewController?
var setTarget: (selector:Selector?,target:UIViewController?) {
get{
return (selector,target)
}
set(newVal) {
selector = newVal.0
target = newVal.1
}
}
var textViewDefaultText = ""
var defaultText: String {
get {
return textViewDefaultText
}
set(newVal) {
textViewDefaultText = newVal
self.text = newVal
self.isEdited = false
}
}
//MARK:- Life Cycle
override init(frame: CGRect, textContainer: NSTextContainer?) {
super.init(frame: frame, textContainer: textContainer)
self.setupTextview()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
self.setupTextview()
}
private func setupTextview(){
// setup textview
self.text = textViewDefaultText
self.delegate = self
}
func updateDefaultText(){
self.defaultText = self.text!
// update save button state
target!.perform(self.selector, with: nil, with: nil)
}
//MARK:- Delegate
internal func textViewDidChange(_ textView: UITextView) {
if textViewDefaultText != textView.text! {
isEdited = true
}else {
isEdited = false
}
// update save button state
target!.perform(self.selector, with: nil, with: nil)
}
}
I hope this helps.