class Checkboxes in Drupal 8

Same name and namespace in other branches

9 core/lib/Drupal/Core/Render/Element/Checkboxes.php \Drupal\Core\Render\Element\Checkboxes

Provides a form element for a set of checkboxes.

Properties:

#options: An associative array whose keys are the values returned for each checkbox, and whose values are the labels next to each checkbox. The #options array cannot have a 0 key, as it would not be possible to discern checked and unchecked states.

Usage example:


$form['high_school']['tests_taken'] = array(
  '#type' => 'checkboxes',
  '#options' => array('SAT' => $this->t('SAT'), 'ACT' => $this->t('ACT')),
  '#title' => $this->t('What standardized tests did you take?'),
  ...
);

Plugin annotation

@FormElement("checkboxes");

Hierarchy

class \Drupal\Component\Plugin\PluginBase implements DerivativeInspectionInterface, PluginInspectionInterface
- class \Drupal\Core\Plugin\PluginBase uses DependencySerializationTrait, MessengerTrait, StringTranslationTrait
  - class \Drupal\Core\Render\Element\RenderElement implements ElementInterface
    class \Drupal\Core\Render\Element\FormElement implements FormElementInterface
    class \Drupal\Core\Render\Element\Checkboxes uses CompositeFormElementTrait

Expanded class hierarchy of Checkboxes

File

core/lib/Drupal/Core/Render/Element/Checkboxes.php, line 31

Namespace

Drupal\Core\Render\Element

View source

class Checkboxes extends FormElement {
  use CompositeFormElementTrait;

  /**
   * {@inheritdoc}
   */
  public function getInfo() {
    $class = get_class($this);
    return [
      '#input' => TRUE,
      '#process' => [
        [
          $class,
          'processCheckboxes',
        ],
      ],
      '#pre_render' => [
        [
          $class,
          'preRenderCompositeFormElement',
        ],
      ],
      '#theme_wrappers' => [
        'checkboxes',
      ],
    ];
  }

  /**
   * Processes a checkboxes form element.
   */
  public static function processCheckboxes(&$element, FormStateInterface $form_state, &$complete_form) {
    $value = is_array($element['#value']) ? $element['#value'] : [];
    $element['#tree'] = TRUE;
    if (count($element['#options']) > 0) {
      if (!isset($element['#default_value']) || $element['#default_value'] == 0) {
        $element['#default_value'] = [];
      }
      $weight = 0;
      foreach ($element['#options'] as $key => $choice) {

        // Integer 0 is not a valid #return_value, so use '0' instead.
        // @see \Drupal\Core\Render\Element\Checkbox::valueCallback().
        // @todo For Drupal 8, cast all integer keys to strings for consistency
        //   with \Drupal\Core\Render\Element\Radios::processRadios().
        if ($key === 0) {
          $key = '0';
        }

        // Maintain order of options as defined in #options, in case the element
        // defines custom option sub-elements, but does not define all option
        // sub-elements.
        $weight += 0.001;
        $element += [
          $key => [],
        ];
        $element[$key] += [
          '#type' => 'checkbox',
          '#title' => $choice,
          '#return_value' => $key,
          '#default_value' => isset($value[$key]) ? $key : NULL,
          '#attributes' => $element['#attributes'],
          '#ajax' => isset($element['#ajax']) ? $element['#ajax'] : NULL,
          // Errors should only be shown on the parent checkboxes element.
          '#error_no_message' => TRUE,
          '#weight' => $weight,
        ];
      }
    }
    return $element;
  }

  /**
   * {@inheritdoc}
   */
  public static function valueCallback(&$element, $input, FormStateInterface $form_state) {
    if ($input === FALSE) {
      $value = [];
      $element += [
        '#default_value' => [],
      ];
      foreach ($element['#default_value'] as $key) {
        $value[$key] = $key;
      }
      return $value;
    }
    elseif (is_array($input)) {

      // Programmatic form submissions use NULL to indicate that a checkbox
      // should be unchecked. We therefore remove all NULL elements from the
      // array before constructing the return value, to simulate the behavior
      // of web browsers (which do not send unchecked checkboxes to the server
      // at all). This will not affect non-programmatic form submissions, since
      // all values in \Drupal::request()->request are strings.
      // @see \Drupal\Core\Form\FormBuilderInterface::submitForm()
      foreach ($input as $key => $value) {
        if (!isset($value)) {
          unset($input[$key]);
        }
      }
      return array_combine($input, $input);
    }
    else {
      return [];
    }
  }

  /**
   * Determines which checkboxes were checked when a form is submitted.
   *
   * @param array $input
   *   An array returned by the FormAPI for a set of checkboxes.
   *
   * @return array
   *   An array of keys that were checked.
   */
  public static function getCheckedCheckboxes(array $input) {

    // Browsers do not include unchecked options in a form submission. The
    // FormAPI tries to normalize this to keep checkboxes consistent with other
    // form elements. Checkboxes show up as an array in the form of option_id =>
    // option_id|0, where integer 0 is an unchecked option.
    //
    // @see \Drupal\Core\Render\Element\Checkboxes::valueCallback()
    // @see https://www.w3.org/TR/html401/interact/forms.html#checkbox
    $checked = array_filter($input, function ($value) {
      return $value !== 0;
    });
    return array_keys($checked);
  }

  /**
   * Determines if all checkboxes in a set are unchecked.
   *
   * @param array $input
   *   An array returned by the FormAPI for a set of checkboxes.
   *
   * @return bool
   *   TRUE if all options are unchecked. FALSE otherwise.
   */
  public static function detectEmptyCheckboxes(array $input) {
    return empty(static::getCheckedCheckboxes($input));
  }

}

Members

Name	Modifiers	Type	Description	Overrides
Checkboxes::detectEmptyCheckboxes	public static	function	Determines if all checkboxes in a set are unchecked.
Checkboxes::getCheckedCheckboxes	public static	function	Determines which checkboxes were checked when a form is submitted.
Checkboxes::getInfo	public	function	Returns the element properties for this element. Overrides ElementInterface::getInfo
Checkboxes::processCheckboxes	public static	function	Processes a checkboxes form element.
Checkboxes::valueCallback	public static	function	Determines how user input is mapped to an element's #value property. Overrides FormElement::valueCallback
CompositeFormElementTrait::preRenderCompositeFormElement	public static	function	Adds form element theming to an element if its title or description is set.
DependencySerializationTrait::$_entityStorages	protected	property	An array of entity type IDs keyed by the property name of their storages.
DependencySerializationTrait::$_serviceIds	protected	property	An array of service IDs keyed by property name used for serialization.
DependencySerializationTrait::__sleep	public	function		1
DependencySerializationTrait::__wakeup	public	function		2
FormElement::processAutocomplete	public static	function	Adds autocomplete functionality to elements.
FormElement::processPattern	public static	function	#process callback for #pattern form element property.
FormElement::validatePattern	public static	function	#element_validate callback for #pattern form element property.
MessengerTrait::$messenger	protected	property	The messenger.	29
MessengerTrait::messenger	public	function	Gets the messenger.	29
MessengerTrait::setMessenger	public	function	Sets the messenger.
PluginBase::$configuration	protected	property	Configuration information passed into the plugin.	1
PluginBase::$pluginDefinition	protected	property	The plugin implementation definition.	1
PluginBase::$pluginId	protected	property	The plugin_id.
PluginBase::DERIVATIVE_SEPARATOR		constant	A string which is used to separate base plugin IDs from the derivative ID.
PluginBase::getBaseId	public	function	Gets the base_plugin_id of the plugin instance. Overrides DerivativeInspectionInterface::getBaseId
PluginBase::getDerivativeId	public	function	Gets the derivative_id of the plugin instance. Overrides DerivativeInspectionInterface::getDerivativeId
PluginBase::getPluginDefinition	public	function	Gets the definition of the plugin implementation. Overrides PluginInspectionInterface::getPluginDefinition	3
PluginBase::getPluginId	public	function	Gets the plugin_id of the plugin instance. Overrides PluginInspectionInterface::getPluginId
PluginBase::isConfigurable	public	function	Determines if the plugin is configurable.
PluginBase::__construct	public	function	Constructs a \Drupal\Component\Plugin\PluginBase object.	92
RenderElement::preRenderAjaxForm	public static	function	Adds Ajax information about an element to communicate with JavaScript.
RenderElement::preRenderGroup	public static	function	Adds members of this group as actual elements for rendering.
RenderElement::processAjaxForm	public static	function	Form element processing handler for the #ajax form property.	1
RenderElement::processGroup	public static	function	Arranges elements into groups.
RenderElement::setAttributes	public static	function	Sets a form element's class attribute. Overrides ElementInterface::setAttributes
StringTranslationTrait::$stringTranslation	protected	property	The string translation service.	1
StringTranslationTrait::formatPlural	protected	function	Formats a string containing a count of items.
StringTranslationTrait::getNumberOfPlurals	protected	function	Returns the number of plurals supported by a given language.
StringTranslationTrait::getStringTranslation	protected	function	Gets the string translation service.
StringTranslationTrait::setStringTranslation	public	function	Sets the string translation service to use.	2
StringTranslationTrait::t	protected	function	Translates a string to the current language or to a given language.

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class Checkboxes in Drupal 8

Plugin annotation

Hierarchy

See also

File

Namespace

Members

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