push推送客户端用receive事件接收payload参数问题

比如

$tosend = array (  
                            'type' => 1,  
                            'content' => 2  
                    );  
$payload = json_encode($tosend );  
$template->set_transmissionContent ($payload );

当payload是json格式的字符串时候，在ios和android下有差异！！
ios下receive事件接收到payload是对象：
{"title":"testapp","payload":{"type":"1","content":"2"}}

但android下确是字符串，如：
{"title":"testapp","payload":"{\"type\":\"1\",\"content\":\"2\"}"}

很郁闷，见图：