Obsolete code in handleTextViewDidChangeNotification

[zyavrik]

The following code is obsolete regarding three commended lines:

- (void)handleTextViewDidChangeNotification:(NSNotification *)notification
{
if (notification.object == self)
{
    CGRect line = [self caretRectForPosition: self.selectedTextRange.start];
    CGFloat overflow = line.origin.y + line.size.height - ( self.contentOffset.y + self.bounds.size.height - self.contentInset.bottom - self.contentInset.top );

    if ( overflow > 0 )
    {
        // We are at the bottom of the visible text and introduced a line feed, scroll down (iOS 7 does not do it)
        // Scroll caret to visible area
        CGPoint offset = self.contentOffset;
        offset.y += overflow + 7; // leave 7 pixels margin
        // Cannot animate with setContentOffset:animated: or caret will not appear
//            [UIView animateWithDuration:.2 animations:^{
//                [self setContentOffset:offset];
//            }];
    }
}
}

[zyavrik]

The initial issue and correct fix for iOS 7.x are described here: http://stackoverflow.com/questions/22315755/ios-7-1-uitextview-still-not-scrolling-to-cursor-caret-after-new-line?lq=1 On iOS 8 the issue is fixed.

[zyavrik]

Another solution can be found here: https://github.com/steipete/PSPDFTextView/blob/master/PSPDFTextView/PSPDFTextView.m

[zyavrik]

Most correct fix:

#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v) ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)
#define is_iOS7 SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0")
#define is_iOS8 SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"8.0")

@implementation CYRTextView {
    ...old code...
    BOOL settingText;
}

- (id)initWithFrame:(CGRect)frame {
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleTextViewDidChangeNotification:) name:UITextViewTextDidChangeNotification object:self];
}

- (void)scrollToCaretInTextView:(UITextView *)textView animated:(BOOL)animated {
    CGRect rect = [textView caretRectForPosition:textView.selectedTextRange.end];
    rect.size.height += textView.textContainerInset.bottom;
    [textView scrollRectToVisible:rect animated:animated];
}

- (void)handleTextViewDidChangeNotification:(NSNotification *)notification {
    if (notification.object == self && is_iOS7 && !is_iOS8 && !settingText) {
        UITextView *textView = self;
        if ([textView.text hasSuffix:@"\n"]) {
            [CATransaction setCompletionBlock:^{
                [self scrollToCaretInTextView:textView animated:NO];
            }];
        } else {
            [self scrollToCaretInTextView:textView animated:NO];
        }
    }
}

- (void)setText:(NSString *)text {
    settingText = YES;
   ...old code..
    settingText = NO;
}