iOS邮件分享有多种方式，我用到的是openURL的方式，这个方式在分享链接时有个问题，如果链接中有用&拼接的参数，当调起邮件时会发现邮件内容中的链接在第一个&符号的地方被截断了导致链接打不开，尝试了很多方法解决了这个问题，在这里分享一下自己的经验。

1、添加邮件的基本信息

 //邮件
  NSMutableString *mailUrl = [[NSMutableString alloc]init];
  //添加收件人
  NSArray *toRecipients = [NSArray arrayWithObject: @""];
  [mailUrl appendFormat:@"mailto:%@", [toRecipients componentsJoinedByString:@","]];
  //添加抄送
  NSArray *ccRecipients = [NSArray arrayWithObjects:@"", @"", nil];
  [mailUrl appendFormat:@"?cc=%@", [ccRecipients componentsJoinedByString:@","]];
  //添加密送
  NSArray *bccRecipients = [NSArray arrayWithObjects:@"", nil];
  [mailUrl appendFormat:@"&bcc=%@", [bccRecipients componentsJoinedByString:@","]];
  //添加主题
  [mailUrl appendString:[NSString stringWithFormat:@"&subject=我用「%@」分享了一张照片",[UserAdmin sharedInstance].appName]];

2、处理邮件内容（带&符号的链接）

  //添加邮件内容
  NSString *endStr = @"https://www.jianshu.com/u/99f4e6822dc6?cardNo=a123&params=a2342414&code=b12313414";
 // 对特殊字符进行转义将&符号替换为%26
  endStr =[endStr stringByReplacingOccurrencesOfString:@"&" withString:@"%26 "];

    [mailUrl appendString:[NSString stringWithFormat:@"&body=点击下面链接查看%@ <br/><br/><br/><br/> <a href=\"%@\">%@</a> <br/><br/><br/><br/> %@，放到手机里，把家人的健康放在心里<br/>",titleType,endStr,endStr,[UserAdmin sharedInstance].appName]];

3、编码后调起邮箱

NSString *email = [mailUrl stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];
  [[UIApplication sharedApplication] openURL:[NSURL URLWithString:email] options:@{UIApplicationOpenURLOptionUniversalLinksOnly:@NO} completionHandler:^(BOOL success) {
           
  }];