How do I define a different administration theme for a user and administration role in Drupal 8?

I have looked at the context module for Drupal 8. There is a problem with the context condition and the reaction theme related items are all based on the front-end themes. I need the same but for the back-end themes.

My code is the same as the context reaction code for Theme.php. I just changed the submitConfiguration().

   * {@inheritdoc}
  public function submitConfigurationForm(array &$form, FormStateInterface $form_state) {
    $configuration['admin'] = $form_state->getValue('theme');
    $configuration += $this->getConfiguration();
          ->set('admin', $form_state->getValue('theme'))

I defined the following in the context configuration.

  1. Condition => Role:User

    Reaction => Admin Theme: Customtheme

  2. Condition => Role: Administrator

    Reaction => Admin Theme: Seven

Is this possible? Are there other methods for achieving this goal?

2 Answers 2


As the context module is still in alpha I would try a solution in custom code by extending the class AdminNegotiator:



namespace Drupal\mymodule\Theme;

use Drupal\user\Theme\AdminNegotiator;
use Drupal\Core\Routing\RouteMatchInterface;

class CustomAdminNegotiator extends AdminNegotiator {

  public function determineActiveTheme(RouteMatchInterface $route_match) {
    if (in_array('custom_role', $this->user->getRoles())) {
      return 'custom_admin_theme';


and register this service class in mymodule.services.yml tagged as theme negotiator with a priority higher than the default admin negotiator (-40):

    class: Drupal\mymodule\Theme\CustomAdminNegotiator
    arguments: ['@current_user', '@config.factory', '@entity.manager', '@router.admin_context']
      - { name: theme_negotiator, priority: -39 }

The applies() method is kept the same as in AdminNegotiator, so that only users with the correct permission have access to this theme and this only applies for admin routes.


I came here just looking for a solution on how to programmatically set the admin theme (say during hook_install or hook_update).

This code will achieve that:

// Make sure the theme is installed
$theme_handler = \Drupal::service('theme_handler');

// Set it as the admin theme
$config = \Drupal::service('config.factory')->getEditable('system.theme');
$config->set('admin', 'my_custom_admin_theme')->save();

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