使用FOSRestBundle（对象数组）返回正确的JSON

Question

我的POST动作看起来像这样：

public function cpostAction(Request $request)
{
    $records = json_decode($request->getContent(), true);
    $arr = array();
    $em = $this->getDoctrine()->getManager();
    foreach((array)$records as $record) {
        $obj = new \stdClass();
        $entity = new Record();
        $entity->setRouteId($record['routeId']);
        $entity->setDate(new \DateTime('now'));
        $entity->setUserId($record['userId']);
        $entity->setSync($record['sync']);
        $obj->id = $record['id'];
        $em->persist($entity);
        $em->flush();
        $obj->remote_id = $entity->getId();
        $obj = json_encode($obj, true);
        array_push($arr, $obj);
    }

    $view = View::create();
    $view->setFormat('json');
    $view->setData($arr);
    return $this->get('fos_rest.view_handler')->handle($view);
}

如果我保留$obj = json_encode($obj, true);，我会收到此回复

[
    "{\"id\":1,\"remote_id\":52}",
    "{\"id\":2,\"remote_id\":53}",
    "{\"id\":3,\"remote_id\":54}"
]

如果没有这行代码，我会得到

{
    "0": {},
    "1": {},
    "2": {}
}

如何获得正确的JSON？ 感谢您的任何建议！