iOS 如何在Label中显示html的文本

if (self.messageModel) {

        NSString * htmlString = self.messageModel.contentText;
 NSAttributedString * attrStr1 = [[NSAttributedString alloc] initWithData:[htmlString dataUsingEncoding:NSUnicodeStringEncoding] options:@{ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType } documentAttributes:nil error:nil];  //就这句有用

        self.messageTextView.attributedText = attrStr1;

        if () {
            NSMutableAttributedString *attrStr = [[NSMutableAttributedString alloc] initWithString:@"【重要】"];
             [attrStr appendAttributedString:attrStr1];
            NSRange range = NSMakeRange(, );
            [attrStr addAttribute:NSForegroundColorAttributeName value:GNHGreenColor range:range];
            self.messageTextView.attributedText = attrStr;
        }
    }

显示如下：