給文字添加下劃線

 UILabel *text = [[UILabel alloc]initWithFrame:CGRectMake(135, 70, 200, 60)];
   NSMutableAttributedString *content = [[NSMutableAttributedString alloc] initWithString:@"需要添加下劃線的文字"];
    
   NSRange contentRange = {0,[content length]};
   [content addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleSingle] range:contentRange];
    
    [text setAttributedText:content];
    [self.view addSubview:text];