Scroll UITextView To Bottom - ios

Question

I am making a an app that has a UITextView and a button.
When I click the button some text will add in the UITextView.
But when clicking the button, I wan't to scroll down to the bottom of the text field so the user can see the last text added.
How to make the UITextView to scroll down to the bottom?
I tried:
int numLines = LogTextView.contentSize.height / LogTextView.font.lineHeight+1;
NSLog(#"%d",numLines);
NSUInteger length = self.LogTextView.text.length;
self.LogTextView.selectedRange = NSMakeRange(0, length);
but it will not work...
I also tried:
self.LogTextView.contentSize=CGSizeMake(length,0);

Answer 1

You can use the following code if you are talking about UITextView:
-(void)scrollTextViewToBottom:(UITextView *)textView {
if(textView.text.length > 0 ) {
NSRange bottom = NSMakeRange(textView.text.length -1, 1);
[textView scrollRangeToVisible:bottom];
}
}
SWIFT 4:
func scrollTextViewToBottom(textView: UITextView) {
if textView.text.count > 0 {
let location = textView.text.count - 1
let bottom = NSMakeRange(location, 1)
textView.scrollRangeToVisible(bottom)
}
}

Answer 2

Try this if you have problem on iOS 7 or above. See this SO answer.
- (void)scrollTextViewToBottom:(UITextView *)textView {
NSRange range = NSMakeRange(textView.text.length, 0);
[textView scrollRangeToVisible:range];
// an iOS bug, see https://stackoverflow.com/a/20989956/971070
[textView setScrollEnabled:NO];
[textView setScrollEnabled:YES];
}

Answer 3

With Swift 3
let bottom = self.textView.contentSize.height - self.textView.bounds.size.height
self.textView.setContentOffset(CGPoint(x: 0, y: bottom), animated: true)

Answer 4

Swift 5
extension UITextView {
func simple_scrollToBottom() {
let textCount: Int = text.count
guard textCount >= 1 else { return }
scrollRangeToVisible(NSRange(location: textCount - 1, length: 1))
}
}
// Usage
textView.simple_scrollToBottom()

Answer 5

Make a range, specifying encoding, to the last character, then scroll to that range
Something other than utf8 might be appropriate depending on your content
let range = NSMakeRange(self.textView.text.lengthOfBytes(using: .utf8), 0);
self.textView.scrollRangeToVisible(range);

Answer 6

You have to implement a delegate method. The code below checks whether a newline has been entered and, if so, scrolls to the bottom of the textView:
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
if ([text isEqualToString:#"\n"]) {
textView.contentOffset = CGPointMake(0.0, textView.contentSize.height);
}
return YES;
}

Answer 7

This works for me! :D
CGPoint bottomOffset = CGPointMake(0, self.textView.contentSize.height - self.textView.bounds.size.height);
[self.description1 setContentOffset:bottomOffset animated:YES];

Answer 8

As a generic approach for scrolling to bottom, it can be done on a UIScrollView.
extension UIScrollView {
func scrollToBottom() {
let contentHeight = contentSize.height - frame.size.height
let contentoffsetY = max(contentHeight, 0)
setContentOffset(CGPoint(x: 0, y: contentoffsetY), animated: true)
}
}
This will work on all descendants of UIScrollView like UITextView, UITableView etc..

Answer 9

textView.scrollRangeToVisible(NSRange(..<textView.text.endIndex, in: textView.text))
This solution does a couple of notable things slightly different:
Utilizes the String.Index interface (likely more performant than e.g. .count)
Uses a PartialRangeUpTo which avoids an explicit range start position, reducing the code to a clean one-liner

Answer 10

The Swift version of #Hong Duan answer
func scrollTextViewToBottom(textView: UITextView) {
if textView.text.count > 0 {
let location = textView.text.count - 1
let bottom = NSMakeRange(location, 1)
textView.scrollRangeToVisible(bottom)
// an iOS bug, see https://stackoverflow.com/a/20989956/971070
textView.isScrollEnabled = false
textView.isScrollEnabled = true
}
}