Scroll to bottom of UITextView erratic in iOS 7

Question

The following code will work fine in iOS < 7.0. In iOS 7 the scrolling will be choppy and erratic while the UITextView is updating. I\'m not sure if this is a bug in iO

Answer 1

Swift 2.0 - IOS 8

This is basically a Swift 2.0 version of dklt's answer above. Previously I was using the same method without the 2 lines of scrollEnabled. Most of the time it works fine. However, when scrollToBottom() is called in quick succession at almost the same time, it doesn't works sometimes.

The 2 lines of scrollEnabled doesn't makes much sense, but after adding them the method works consistently!

Note: I have tried to put the 2 lines of scrollEnabled in various position before or after the scrollRangeTovisible, as was suggested in dklt's answer's comments...

ONLY dklt's original solution works for me. The rest doesn't.

func scrollToBottom()
{
    let range:NSRange = NSMakeRange(self.textView.text.characters.count - 1, 1)

    self.textView.scrollRangeToVisible(range)
    self.textView.scrollEnabled = false
    self.textView.scrollEnabled = true
}

Answer 2

Basically setScrollEnabled = YES need to be set before layoutSubviews get called. It worked for me.

Answer 3

For those who are using Swift, I post here the same answer as RawMean (thanks again!). As I wrote this (dec. 2014), the problem still exist in iOS 8.1 and his solution work perfectly...

var textView: UITextView!
var textStorage: NSTextStorage!
var layoutManager: NSLayoutManager!
var textContainer: NSTextContainer!


override func viewDidLoad() {
    textStorage = NSTextStorage()
    layoutManager = NSLayoutManager()
    textStorage.addLayoutManager(layoutManager)

    let newTextViewRect = view.bounds
    let containerSize = CGSize(width: newTextViewRect.width, height: CGFloat.max)

    textContainer = NSTextContainer(size: containerSize)
    layoutManager.addTextContainer(textContainer)

    textView = UITextView(frame: newTextViewRect, textContainer: textContainer)

    textView.delegate = self
    view.addSubview(textView)

}

override func viewDidLayoutSubviews() {
    textView.frame = view.bounds
}

and I used the scrollRangeToVisible method to scroll smoothly at the bottom as text is added...

let length = countElements(textView.text)
let range:NSRange = NSMakeRange(length - 1, 1)
textView.scrollRangeToVisible(range)