关于使用phpqrcode二维码无法显示的问题

define('bestfenxiao_PATH', dirname(__FILE__).'/../');
require_once bestfenxiao_PATH.'source/init.php';

$type = isset($_GET['type']) ? $_GET['type'] : redirect($_G['config']['site_url'].'/static/images/no_qrcode.png');
$id = isset($_GET['id']) ? $_GET['id'] : redirect($_G['config']['site_url'].'/static/images/no_qrcode.png');
switch($type){
case 'home':
$url = $_G['config']['wap_site_url'].'/home.php?id='.$id;
break;
case 'page_cat':
$url = $_G['config']['wap_site_url'].'/pagecat.php?id='.$id;
break;
case 'page':
$url = $_G['config']['wap_site_url'].'/page.php?id='.$id;
break;
case 'good_cat':
$url = $_G['config']['wap_site_url'].'/goodcat.php?id='.$id;
break;
case 'good':
$url = $_G['config']['wap_site_url'].'/good.php?id='.$id.(isset($_GET['activity']) ? '&activity='.$_GET['activity'] : '');
break;
case 'ucenter':
$url = $_G['config']['wap_site_url'].'/ucenter.php?id='.$id;
break;
case 'activity':
$url = urldecode($_GET['url']);
break;
default:
redirect($_G['config']['site_url'].'/static/images/no_qrcode.png');
}
import('phpqrcode');
ob_clean();//这个一定要加上，清除缓冲区
QRcode::png(urldecode($url),false,0,7,2);