UILabel设置下划线

    NSMutableAttributedString *content = [[NSMutableAttributedStringalloc] initWithString:[NSStringstringWithFormat:@"用户协议"]];

    NSRange contentRange = {0,[contentlength]};

    [content addAttribute:NSUnderlineStyleAttributeNamevalue:[NSNumbernumberWithInteger:NSUnderlineStyleSingle]range:contentRange];

    userAgreementLabel.attributedText =content;