Doing a simple checkbox in field API

Question

I'm trying to add a simple checkbox in a Drupal 8 Entity Form that displays like the old Form API:

$form['approved'] = [
  '#type' => 'checkbox',
  '#title' => t('Approved'),
  '#description' => t('Check this to indicate this person is approved for membership'),
];

Using D8 style field definitions, this should be something like

$fields['approved'] = BaseFieldDefinition::create('boolean')
  ->setLabel(t('Approved'))
  ->setDescription(t('Volunteer is approved for trusted work.'))
  ->setSettings(array(
    'display_label' => TRUE,
  ))
  ->setDisplayOptions('view', array(
    'type' => 'unicode-yes-no',
    'weight' => -3,
  ))
  ->setDisplayOptions('form', array(
    'type' => 'boolean_checkbox',
    'weight' => -3,
  ))
  ->setDisplayConfigurable('form', TRUE)
  ->setDisplayConfigurable('view', TRUE);

This doesn't quite work; I'm getting a checkbox with the label "On".

How do I fix this? Also has anybody gathered the various parameters used for setDisplayOptions() in one place and documented how these map to the Form API and the Render API? I've been looking at the sources in core/lib/Drupal/Core, and I'm not finding much. And there isn't even a test for the boolean_checkbox widget, so no code to look at there either.

Answer 1

You can always just create a field in the UI and extract the settings from there. Or look at the defaultSettings() method in the plugin class, where you can find this:

/**
 * {@inheritdoc}
 */
public static function defaultSettings() {
  return array(
    'display_label' => FALSE,
  ) + parent::defaultSettings();
}

So, add 'settings' => ['display_label' => TRUE] to your form display definition and you have what you want.

Answer 2

@Bendir has the right idea, but for my field, the configuration was spread over four different config files. These were, for adding a field "approved_example" to the "Article" node type:

• field.field.node.article.field_approval_example.yml
• field.storage.node.field_approval_example.yml
• core.entity_form_display.node.article.default.yml
• core.entity_view_display.node.article.default.yml

    $fields['approved'] = BaseFieldDefinition::create('boolean')
     ->setLabel(t('Approved'))
     ->setDescription(t('Volunteer is approved for trusted work.'))
     ->setDisplayOptions('view', array(
       'settings' => [
         'format' => 'unicode-yes-no',
       ],
       'weight' => -3,
     ))
     ->setDisplayOptions('form', array(
       'settings' => [
         'display_label' => TRUE,
       ],
       'type' => 'boolean_checkbox',
       'weight' => -3,
     ))
     ->setDisplayConfigurable('form', TRUE)
     ->setDisplayConfigurable('view', TRUE);

The documentation problem is that settings can appear at several levels, and that the distinction between "options" and "settings" is not clear in the documentation.

I also think that making On/Off buttons the default UI for fields was the wrong thing for Core to do -- even getting a simple checkbox done in the UI is not very discoverable -- but the code in this answer seems to do the trick.