UITextView issues in iOS6 and iOS7

UITextView is so buggy on iOS6/iOS7...

line spacing

// adjust lineSpacing
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
style.minimumLineHeight = LINE_HEIGHT;
style.maximumLineHeight = LINE_HEIGHT;
style.lineHeightMultiple = LINE_HEIGHT;
// Bug: NSFontAttributeName not working in ios6
NSDictionary *attributes = @{
                           NSParagraphStyleAttributeName : style,
[textView setAttributedText:[[NSAttributedString alloc] initWithString:content attributes:attributes]];

font size

//Fixed: font-size not working in ios6
[textView setEditable:YES];
[textView setFont:[UIFont fontWithName:@"Helvetica" size:FONT_SIZE]];
[textView setEditable:NO];


// in iOS6
[textView sizeToFit];
NSLog(@"height:%f", [textView contentSize].height);

in iOS6
height: 416

not working in iOS7
height: 292

[textView setFrame:CGRectMake(10, 10, 300, [self measureHeightOfUITextView:textView])];
NSLog(@"height:%f", [self measureHeightOfUITextView:textView]);
- (CGFloat)measureHeightOfUITextView:(UITextView *)textView
  return [textView sizeThatFits:CGSizeMake(textView.frame.size.width, FLT_MAX)].height;

in iOS6
height: 416

in iOS7
height: 366

Added a screenshot for the final results.

combining all code.
I also create an category for UITextView+Additions.