SLIM 3：PHP变量

Question

im using slim for the first time and want to know why i get undefined in $file variable. Do i have to add the variables to the container or how it works? How the cycle works?, neither work if i add var_dump inside the get.

In another area of the site i use define, but i think it´s not the best way.

Hope you can help.

$app->get('/path/{id}-{title}', function ($request, $response, $args) {

switch ($args['id']) {
    case '1':
        $file = 'pathtofile';
        break;
    case '2':
        $file = 'pathtofile2';
        break;
}

var_dump($args);

return $this->view->render($response, $file.'.html', [
    'id' => $args['id'],
    'title' => $args['title']
]);
})->setName('path');

Thanks