Step-1: Get instance of messenger service
Method 1
Standard way to get messenger service, in case you want to pass it using dependency injection.
$messenger = \Drupal::service("messenger");
Method 2
Fast way to use helper function.
$messenger = \Drupal::messenger();
Also in the form object or controller we don’t have include it using dependency injection. We can us directly
$messenger = $this->messenger();
Step-2: Adding info/warn/error message
Add message. Allows to send a message of any type, the second parameter accepts the type: $meesenger->addMessage(t('Your message.'), MessengerInterface::TYPE_WARNING);; But in most of the cases it is better to use directly specific method:
- Add Status Message:
$messenger->addStatus(t('Your message')); - Add Warning/Debug:
$messenger->addWarning(t('Your message')); - Add Error Message:
$messenger->addError(t('Your message'));
Step-3: Check the final outcome
