interface ThemeNegotiatorInterface in Drupal 9

Defines an interface for classes which determine the active theme.

To set the active theme, create a new service tagged with 'theme_negotiator' (see the theme.negotiator.admin_theme service in user.services.yml for an example). Your service class needs to implement this interface.

If you are setting a theme which is closely tied to the functionality of a particular page or set of pages (such that the page might not function correctly if a different theme is used), make sure to set the priority on the service to a high number so that it is not accidentally overridden by other theme negotiators. By convention, a priority of "1000" is used in these cases; see \Drupal\Core\Theme\AjaxBasePageNegotiator and core.services.yml for an example.

Hierarchy

• interface \Drupal\Core\Theme\ThemeNegotiatorInterface

8 files declare their use of ThemeNegotiatorInterface

AdminDemoNegotiator.php in core/modules/block/src/Theme/AdminDemoNegotiator.php

AdminNegotiator.php in core/modules/user/src/Theme/AdminNegotiator.php

BatchNegotiator.php in core/modules/system/src/Theme/BatchNegotiator.php

CustomThemeNegotiator.php in core/modules/system/tests/modules/theme_test/src/Theme/CustomThemeNegotiator.php

DbUpdateNegotiator.php in core/modules/system/src/Theme/DbUpdateNegotiator.php

... See full list

File

core/lib/Drupal/Core/Theme/ThemeNegotiatorInterface.php, line 22

Namespace

Drupal\Core\Theme

interface ThemeNegotiatorInterface {

  /**
   * Whether this theme negotiator should be used to set the theme.
   *
   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
   *   The current route match object.
   *
   * @return bool
   *   TRUE if this negotiator should be used or FALSE to let other negotiators
   *   decide.
   */
  public function applies(RouteMatchInterface $route_match);

  /**
   * Determine the active theme for the request.
   *
   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
   *   The current route match object.
   *
   * @return string|null
   *   The name of the theme, or NULL if other negotiators, like the configured
   *   default one, should be used instead.
   */
  public function determineActiveTheme(RouteMatchInterface $route_match);

}

Members

Name	Modifiers	Type	Description	Overrides
ThemeNegotiatorInterface::applies	public	function	Whether this theme negotiator should be used to set the theme.	10
ThemeNegotiatorInterface::determineActiveTheme	public	function	Determine the active theme for the request.	10