iOS7 UITextView 光标问题

最近在项目中遇到UITextView在ios7上出现编辑进入最后一行时光标消失，看不到最后一行，变成盲打，stackOverFlow网站上有大神指出，是ios7本身bug，加上下面一段代码即可：

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

 2     CGRect line = [textView caretRectForPosition:

 3                    textView.selectedTextRange.start];

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

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

 6        - textView.contentInset.bottom - textView.contentInset.top );

 7     if ( overflow > 0 ) {

 8         // We are at the bottom of the visible text and introduced a line feed, scroll down (iOS 7 does not do it)

 9         // Scroll caret to visible area

10         CGPoint offset = textView.contentOffset;

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

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

13         [UIView animateWithDuration:.2 animations:^{

14             [textView setContentOffset:offset];

15         }];

16     }

17 }