template_preprocess_file_widget_multiple

template_preprocess_file_widget_multiple(&$variables)

function template_preprocess_file_widget_multiple(&$variables) {
  $element = $variables['element'];

  // Special ID and classes for draggable tables.
  $weight_class = $element['#id'] . '-weight';
  $table_id = $element['#id'] . '-table';

  // Build up a table of applicable fields.
  $headers = array();
  $headers[] = t('File information');
  if ($element['#display_field']) {
    $headers[] = array(
      'data' => t('Display'),
      'class' => array('checkbox'),
    );
  }
  $headers[] = t('Weight');
  $headers[] = t('Operations');

  // Get our list of widgets in order (needed when the form comes back after
  // preview or failed validation).
  $widgets = array();
  foreach (Element::children($element) as $key) {
    $widgets[] = &$element[$key];
  }
  usort($widgets, '_field_multiple_value_form_sort_helper');

  $rows = array();
  foreach ($widgets as $key => &$widget) {
    // Save the uploading row for last.
    if (empty($widget['#files'])) {
      $widget['#title'] = $element['#file_upload_title'];
      $widget['#description'] = \Drupal::service('renderer')->renderPlain($element['#file_upload_description']);
      continue;
    }

    // Delay rendering of the buttons, so that they can be rendered later in the
    // "operations" column.
    $operations_elements = array();
    foreach (Element::children($widget) as $sub_key) {
      if (isset($widget[$sub_key]['#type']) && $widget[$sub_key]['#type'] == 'submit') {
        hide($widget[$sub_key]);
        $operations_elements[] = &$widget[$sub_key];
      }
    }

    // Delay rendering of the "Display" option and the weight selector, so that
    // each can be rendered later in its own column.
    if ($element['#display_field']) {
      hide($widget['display']);
    }
    hide($widget['_weight']);

    // Render everything else together in a column, without the normal wrappers.
    $widget['#theme_wrappers'] = array();
    $information = drupal_render($widget);
    $display = '';
    if ($element['#display_field']) {
      unset($widget['display']['#title']);
      $display = array(
        'data' => render($widget['display']),
        'class' => array('checkbox'),
      );
    }
    $widget['_weight']['#attributes']['class'] = array($weight_class);
    $weight = render($widget['_weight']);

    // Arrange the row with all of the rendered columns.
    $row = array();
    $row[] = $information;
    if ($element['#display_field']) {
      $row[] = $display;
    }
    $row[] = $weight;

    // Show the buttons that had previously been marked as hidden in this
    // preprocess function. We use show() to undo the earlier hide().
    foreach (Element::children($operations_elements) as $key) {
      show($operations_elements[$key]);
    }
    $row[] = array(
      'data' => $operations_elements,
    );
    $rows[] = array(
      'data' => $row,
      'class' => isset($widget['#attributes']['class']) ? array_merge($widget['#attributes']['class'], array('draggable')) : array('draggable'),
    );
  }

  $variables['table'] = array(
    '#type' => 'table',
    '#header' => $headers,
    '#rows' => $rows,
    '#attributes' => array(
      'id' => $table_id,
    ),
    '#tabledrag' => array(
      array(
        'action' => 'order',
        'relationship' => 'sibling',
        'group' => $weight_class,
      ),
    ),
    '#access' => !empty($rows),
  );

  $variables['element'] = $element;
}