How do i force a text format and hide the format selector in a formatted text field?

Question

I Want to force a certain text format in a user profile text format field and hide the text format selector dropdown. How do i do it? This is for Drupal 8.

Answer 1

Install the module Allowed Formats and configure the field to allow only one text format. Then the text format selector dropdown will no longer be displayed.

Answer 2

Adapted from the Allowed Formats code:

use Drupal\Core\Form\FormStateInterface;

/**
 * Implements hook_field_widget_form_alter().
 */
function mymodule_field_widget_form_alter(&$element, FormStateInterface $form_state, $context) {
  // Maps field names to an array containing a single format.
  $map = [
    'field_myfield' => ['myformat'],
  ];

  $field_name = $context['items']->getFieldDefinition()->getName();

  if (array_key_exists($field_name, $map)) {
    $element['#allowed_formats'] = $map[$field_name];
    $element['#after_build'][] = '_remove_text_format_box';
  }
}

/**
 * #after_build callback.
 */
function _remove_text_format_box($form_element, FormStateInterface $form_state) {
  // Remove help, guidelines and wrapper.
  unset($form_element['format']['help']);
  unset($form_element['format']['guidelines']);
  unset($form_element['format']['#type']);
  unset($form_element['format']['#theme_wrappers']);

  return $form_element;
}

Answer 3

If you use the #allowed_formats value and limit it to just 1 value; then the selector will disappear. This is code to add your own custom field; but I assume you can do a form alter to set these for an existing (UI placed) field.

$form['message_text'] = [
  '#type' => 'text_format',
  '#format' => 'simple',
  '#allowed_formats' => ['simple'],
  '#title' => $this->t('Message Text:'),
  '#description' => $this->t('Some help text here.'),
];