IOS 7 textview contentsize offset : textview contentsize 스크롤

IOS7이 되고 나서  텍스트 뷰에서 글 작성 할때 키보드로 글이 내려가 버리는 현상 발견 .. ~ ㅠㅠ

- (void)textViewDidChange:(UITextView *)textView {

    CGRect line = [textView caretRectForPosition:

                   textView.selectedTextRange.start];

    CGFloat overflow = line.origin.y + line.size.height

    - ( textView.contentOffset.y + textView.bounds.size.height

       - textView.contentInset.bottom - textView.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 = textView.contentOffset;

        offset.y += overflow + 7; // leave 7 pixels margin

        // Cannot animate with setContentOffset:animated: or caret will not appear

        [UIView animateWithDuration:.2 animations:^{

            [textView setContentOffset:offset];

        }];

    }

}