UILabel行数间隔

 //调整行间距

    NSMutableAttributedString *attributedString = [[NSMutableAttributedStringalloc]
initWithString:_contentLb.text];

    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStylealloc]
init];

    [paragraphStyle setLineSpacing:6];

    [attributedString addAttribute:NSParagraphStyleAttributeNamevalue:paragraphStyle
range:NSMakeRange(0, [_contentLb.textlength])];

    _contentLb.attributedText = attributedString;