Example on how to prevent reordering of paragraphs field forms (and other forms) #drupal #form-api #tabledrag

paragraphs_disable_drag_add.php

<?php
/**
 * Removes item sort/add/remove capabilities.
 * 
 * When called on an element during hook_field_attach_form(), this function
 * ensures that no item can be added, removed or reordered.
 * Currently adjusted to paragraphs. The core MV widget may required different
 * button keys.
 */
function EXAMPLE_lock_paragraphs_multiple_value_form(&$element) {
  if(empty($element[$element['#language']])) {
    // For safety only. This case might never happen.
    return;
  }
  $items = &$element[$element['#language']];
  foreach(element_children($items) as $delta) {
    // Disables the remove button, preventing the item from getting deleted.
    if(isset($items[$delta]['actions']['remove_button'])) {
      $items[$delta]['actions']['remove_button']['#access'] = false;
    }
    // Convert weight elements to hidden, to retain their value in
    // $form_state['input'] without allowing user chances.
    if(isset($items[$delta]['_weight'])) {
      $items[$delta]['_weight'] = array(
        '#type' => 'hidden',
        '#value' => $items[$delta]['_weight']['#default_value']
      // Add back original keys, in case other modules rely on them.
      ) + $items[$delta]['_weight'];
    }
  }
  // Disable the add_more button. This prevents additional items from being
  // added.
  if(isset($items['add_more'])) {
    $items['add_more']['#access'] = false;
  }
  $items['#post_render'][] = 'EXAMPLE_disable_tabledrag';
}

/**
 * Disables tableDrag by removing related JS settings.
 * 
 * If this function has been specified as #post_render callback on an element,
 * it is fairly safe to assume that the last call to drupal_add_js() added
 * tableDrag related settings. This function identifies these settings via
 * the generated table id and removes them.
 */
function EXAMPLE_disable_tabledrag($element, $children) {
  $html_ids = drupal_static('drupal_html_id');
  // Per reference, as we might remove an entry
  $js = &drupal_static('drupal_add_js');

  if(!empty($js['settings']['data'])) {
    // Fetch the latest js settings entry
    $data_last = end($js['settings']['data']);
    // The table ID created by theme_multiple_value_form
    $table_id = $children['#field_name'] . '_values';
    // Apply sanitizing from drupal_html_id(). Not very DRY, but it's not
    // like we have a choice here.
    $table_id = strtr(drupal_strtolower($table_id), array(' ' => '-', '_' => '-', '[' => '-', ']' => ''));
    $table_id = preg_replace('/[^A-Za-z0-9\-_]/', '', $table_id);
    $table_id = preg_replace('/\-+/', '-', $table_id);
    // Verify that the html id actually exists, and append a counter if needed.
    if(isset($html_ids[$table_id])) {
      $table_id = $html_ids[$table_id] === 1 ? $table_id : "$table_id--" . $html_ids[$table_id];
      // Finally check if we guessed right and there are tableDrag settings for
      // our table ID.
      if(isset($data_last['tableDrag'][$table_id])) {
        // ... and get rid of them.
        array_pop($js['settings']['data']);
      }
    }
  }
  return $element;
}