PHPMailer邮件标题中文乱码的解决方法

<?php
/**
 * PHPMailer邮件发送
 * Edit www.jb200.com
*/
 function smtp_main_send( $to, $subject, $message, $from, $fromName )
 {
   $mail = new PHPMailer();

   $mail->CharSet = "UTF-8"; // 设置编码

   $mail->IsSMTP(); // 设置使用SMTP服务发送
   $mail->Host = "smtp.mail.com";
   $mail->Username = "user";
   $mail->Password = "pass";
   $mail->SMTPAuth = true;

   $mail->From = $from;
   $mail->FromName = $fromName;

   if ( is_array( $to ) ) {
     foreach ( $to as $address ) {
       $mail->AddAddress( $address );
     }
   } else {
     $mail->AddAddress( $to );
   }

   $mail->Subject = $subject;
   $mail->Body = $message;
   $mail->AltBody = $message;
   $mail->IsHTML( true );

   return $mail->Send();
 }
?>

function EncodeHeader ($str, $position = 'text', $pl = 0) {
   if ( $pl ) return "=?" . $this->CharSet . "?B?" . base64_encode($str) . "?=";

$result .= $this->HeaderLine("Subject", $this->EncodeHeader(trim($this->Subject),'text', 1));