怎么得到return 的值，

		public function huancheng($key)<br />		{<br />             $key="永兴村到山水人家";<br />             $str="";<br />		     $keys=explode('到',$key);<br />             $json = @file_get_contents("http://api.map.baidu.com/direction/v1?mode=transit&origin=".$keys[0]."&destination=".$keys[1]."&region=舟山&output=json&ak=gfPnxaaiPyNIhM7c3eZ1kmEL");<br />             $ar = json_decode($json,true);<br />             array_walk_recursive($ar, 'funv');<br />             function funv($v, $k) <br />			 {<br />			   global $str;<br />               if($k == 'stepInstruction') <br />			   {$str.= strip_tags($v);} <br />			 }<br />			 return $str;	<br />         }