Warning: Invalid argument supplied for foreach

foreach 전 is_array 나 is_object 인경우에만 foreach 실행

<?

$url="http://wwww.aaa.com/rss/rss_m_utf8.php?uid=1331";

$xml = @simplexml_load_file($url);

                if(is_array($xml->channel->item->read_r_news->r_url) || is_object($xml->channel->item->read_r_news->r_url) ) {

foreach($xml->channel->item->read_r_news->r_url as $item) {

echo $item->url.": $item :: <br>";

} 

}

?>