UILabel设置行高

NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:self.tipsLabel.text];

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
[paragraphStyle setLineSpacing:4];
[attributedString addAttribute:NSParagraphStyleAttributeName
                         value:paragraphStyle
                         range:NSMakeRange(0, [self.tipsLabel.text length])];

self.tipsLabel.attributedText = attributedString;