11/03/2020, by Ivan

In the previous article we had a look how to integrate Views modules with custom database for Did this help? module:

https://www.drupal.org/project/did_this_help

In this articles we will override Views filter for  Choice (yes/no) field:

Yes/no field

Now it's usual text field created by "string" handler, which allows to add search key. But we have only two options Yes/No, so it would be better to have dropbox instead of textfield. Let's create a file /did_this_help/src/Plugin/views/filter/DidThisHelp.php:

<?php

namespace Drupal\did_this_help\Plugin\views\filter;

use Drupal\views\Plugin\views\filter\InOperator;

/**
 * Filters by given list of yes/no options.
 *
 * @ingroup views_filter_handlers
 *
 * @ViewsFilter("did_this_help")
 */
class DidThisHelp extends InOperator {

}

We will inherit DidThisHelp class from parent InOperator class, which provides filter with select dropbox, radio buttons or checkboxes depends on Views UI settings. 

In method getValueOptions() we will add list of available options:

  /**
   * {@inheritdoc}
   */
  public function getValueOptions() {
    if (isset($this->valueOptions)) {
      return $this->valueOptions;
    }

    $this->valueOptions = [
      'yes' => $this->t('Yes'),
      'no' => $this->t('No'),
    ];

    return $this->valueOptions;
  }

Property valueOptions has been defined in parent class InOperator, so we need to define only array of options.

In results we got that filter:

Yes/No filter

If we enabled exposed filter, then we see this dropbox:

Yes/No dropdown

You can override any Filter class from this list of classes provided by Views and other modules:

Name Location Description
Access core/modules/node/src/Plugin/views/filter/Access.php Filter by node_access records.
BooleanOperator core/modules/views/src/Plugin/views/filter/BooleanOperator.php Simple filter to handle matching of boolean values
BooleanOperatorString core/modules/views/src/Plugin/views/filter/BooleanOperatorString.php Simple filter to handle matching of boolean values.
Broken core/modules/views/src/Plugin/views/filter/Broken.php A special handler to take the place of missing or broken handlers.
Bundle core/modules/views/src/Plugin/views/filter/Bundle.php Filter class which allows filtering by entity bundles.
Current core/modules/user/src/Plugin/views/filter/Current.php Filter handler for the current user.
Date core/modules/datetime/src/Plugin/views/filter/Date.php Date/time views filter.
Date core/modules/views/src/Plugin/views/filter/Date.php Filter to handle dates stored as a timestamp.
Equality core/modules/views/src/Plugin/views/filter/Equality.php Simple filter to handle equal to / not equal to filters
FilterBooleanOperatorDefaultTest core/modules/views/tests/modules/views_test_data/src/Plugin/views/filter/FilterBooleanOperatorDefaultTest.php Filter to test queryOpBoolean() with default operator.
FilterPluginBase core/modules/views/src/Plugin/views/filter/FilterPluginBase.php Base class for Views filters handler plugins.
GroupByNumeric core/modules/views/src/Plugin/views/filter/GroupByNumeric.php Simple filter to handle greater than/less than filters
HistoryUserTimestamp core/modules/history/src/Plugin/views/filter/HistoryUserTimestamp.php Filter for new content.
InOperator core/modules/views/src/Plugin/views/filter/InOperator.php Simple filter to handle matching of multiple options selectable via checkboxes
LanguageFilter core/modules/views/src/Plugin/views/filter/LanguageFilter.php Provides filtering by language.
LatestRevision core/modules/views/src/Plugin/views/filter/LatestRevision.php Filter to show only the latest revision of an entity.
ListField core/modules/options/src/Plugin/views/filter/ListField.php Filter handler which uses list-fields as options.
ManyToOne core/modules/views/src/Plugin/views/filter/ManyToOne.php Complex filter to handle filtering for many to one relationships, such as terms (many terms per node) or roles (many roles per user).
ModerationStateFilter core/modules/content_moderation/src/Plugin/views/filter/ModerationStateFilter.php Provides a filter for the moderation state of an entity.
Name core/modules/user/src/Plugin/views/filter/Name.php Filter handler for usernames.
NodeComment core/modules/comment/src/Plugin/views/filter/NodeComment.php Filter based on comment node status.
NumericFilter core/modules/views/src/Plugin/views/filter/NumericFilter.php Simple filter to handle greater than/less than filters
Permissions core/modules/user/src/Plugin/views/filter/Permissions.php Filter handler for user roles.
Roles core/modules/user/src/Plugin/views/filter/Roles.php Filter handler for user roles.
Search core/modules/search/src/Plugin/views/filter/Search.php Filter handler for search keywords.
Standard core/modules/views/src/Plugin/views/filter/Standard.php Default implementation of the base filter plugin.
StatisticsLastUpdated core/modules/comment/src/Plugin/views/filter/StatisticsLastUpdated.php Filter handler for the newer of last comment / node updated.
Status core/modules/file/src/Plugin/views/filter/Status.php Filter by file status.
Status core/modules/node/src/Plugin/views/filter/Status.php Filter by published status.
StringFilter core/modules/views/src/Plugin/views/filter/StringFilter.php Basic textfield filter to handle string filtering commands including equality, like, not like, etc.
TaxonomyIndexTid core/modules/taxonomy/src/Plugin/views/filter/TaxonomyIndexTid.php Filter by term id.
TaxonomyIndexTidDepth core/modules/taxonomy/src/Plugin/views/filter/TaxonomyIndexTidDepth.php Filter handler for taxonomy terms with depth.
UidRevision core/modules/node/src/Plugin/views/filter/UidRevision.php Filter handler to check for revisions a certain user has created.
UserUid core/modules/comment/src/Plugin/views/filter/UserUid.php Filter handler to accept a user id to check for nodes that user posted or commented on.
UserUid core/modules/tracker/src/Plugin/views/filter/UserUid.php UID filter to check for nodes that a user posted or commented on.
ViewsFilter core/modules/views/src/Annotation/ViewsFilter.php Defines a Plugin annotation object for views filter handlers.
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