I got FatalErrorException: for trying to create custom action in sonata admin

Question

I got the following error when I add a custom action in Sonata Admin

FatalErrorException: Error: Class 'Symfony\Component\Debug\Exception\FlattenException' not found in /myproject_path/AppBundle/Admin/BalticsAdmin.php line 106

What is this problem please share me

HERE IS THE CODE

In admin class

protected function configureListFields(ListMapper $listMapper)
{
    $listMapper
        ................................
        .................
        ->add('_action', 'actions', array(
            'actions' => array(
                'show' => array(),
                'edit' => array(),
                'delete' => array(),
                'upload' => array('template' => 'SteelGuruBundle:CRUD:list__action_upload.html.twig'),
            )
        ));
}

protected function configureRoutes(RouteCollection $collection)
{
    $collection->add('upload', $this->getRouterIdParameter().'/upload');
}

THEN I cREATE a controller class in src/.../.../Controller/CRUDController.php with following codes

namespace ...\AppBundle\Controller;

use Sonata\AdminBundle\Controller\CRUDController as Controller;

class CRUDController extends Controller
{
public function uploadAction()
{
    $id = $this->get('request')->get($this->admin->getIdParameter());

    $object = $this->admin->getObject($id);

    if (!$object) {
        throw new NotFoundHttpException(sprintf('unable to find the object with id : %s', $id));
    }

}
}

Then I create a template in src/.../AppBundle/Resources/views/CRUD/list__action_upload.html.twig with the following code

<a class="btn btn-small" href="{{ admin.generateObjectUrl('upload', object) }}">Upload</a>

and then in services.yml I added the following

sg_app.admin.baltic:
    class: ...\AppBundle\Admin\BalticsAdmin
    tags:
        - { name: sonata.admin, manager_type: orm, audit:false, group: Test, label: Upload}
    arguments: [null, ...\AppBundle\Entity\Baltics, ...AppBundle:CRUD]

Thanks for your response

Answer 1

i had a similar problem and found out that i had to add

use Sonata\AdminBundle\Route\RouteCollection;

to the Admin (in your case BalticAdmin).