UITextView automatic scroll down

Question

I have an UIView and I add a editable UITextView to it,

UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake(5, 5, 2         


        

Answer 1

if found a solution

i put the textview into a view and set the view to clipToBounds = YES then i put the textView to a height of 70

that fixed the problem.

very strange solution, but it finally works :)

Answer 2

I think you'll have to do

[textView scrollRangeToVisible:[textView selectedRange]];

in textDidChange.

Answer 3

To scroll to the end of the buffer I tried

[textView scrollRangeToVisible:NSMakeRange([textView.text length]-1, 1)];

But nothing happened. Instead this works

textView.selectedRange = NSMakeRange(textView.text.length - 1, 0);

Answer 4

I found that if the text added to the UITextView contained carriage returns, then the textview would not scroll correctly.

I added the logic as follows to allow the bounds to be correctly calculated before scrolling to range.

BOOL autoscroll = NO;

//I added a 10 px buffer here to allow for better detection as the textview is auto populated 
if (textView.contentOffset.y >= (textView.contentSize.height - textView.frame.size.height - 10))
{
    autoscroll = YES;
}

[textView setText:messageString];
[textView layoutSubviews];

if(autoscroll) {
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.1 * NSEC_PER_SEC)),     dispatch_get_main_queue(), ^{
        [textView scrollRangeToVisible:NSMakeRange(textView.text.length - 1, 1)];
    });
}

Answer 5

When adding text to a text box programmatically, I found I also needed to add "[textView layoutIfNeeded]" to set things up before the new scroll position could be calculated correctly.

for example:

[newString appendFormat:@"%@\n",addText];
textView.text = newString;
[textView layoutIfNeeded];
NSRange range = NSMakeRange(textView.text.length - 2, 1); //I ignore the final carriage return, to avoid a blank line at the bottom
[textView scrollRangeToVisible:range]

Without this addition the textbox would sometimes not scroll, or would scroll several lines every time a single line of data was added.

Answer 6

This works:

- (void)textViewDidChange:(UITextView *)textView {
    if (_moveToBottom) {
        int y = textView.contentSize.height - textView.frameHeight + self.textView.contentInset.bottom + self.textView.contentInset.top;
        if(y > 0) {
            [textView setContentOffset:CGPointMake(0, y) animated:YES];
        }
        _moveToBottom = NO;
    }
    else {
        [textView scrollRangeToVisible:NSMakeRange([textView.text length]-1, 1)];
    }
}

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
    if ([text isEqualToString:@"\n"] && range.location == [textView.text length]) {
        _moveToBottom = YES;
    }
    return YES;
}