TranslateEditForm::buildForm

public TranslateEditForm::buildForm(array $form, FormStateInterface $form_state)

public function buildForm(array $form, FormStateInterface $form_state) {
  $filter_values = $this->translateFilterValues();
  $langcode = $filter_values['langcode'];

  $this->languageManager->reset();
  $languages = $this->languageManager->getLanguages();

  $langname = isset($langcode) ? $languages[$langcode]->getName() : "- None -";

  $form['#attached']['library'][] = 'locale/drupal.locale.admin';

  $form['langcode'] = array(
    '#type' => 'value',
    '#value' => $filter_values['langcode'],
  );

  $form['strings'] = array(
    '#type' => 'table',
    '#tree' => TRUE,
    '#language' => $langname,
    '#header' => [
      $this->t('Source string'),
      $this->t('Translation for @language', ['@language' => $langname]),
    ],
    '#empty' => $this->t('No strings available.'),
    '#attributes' => ['class' => ['locale-translate-edit-table']],
  );

  if (isset($langcode)) {
    $strings = $this->translateFilterLoadStrings();

    $plurals = $this->getNumberOfPlurals($langcode);

    foreach ($strings as $string) {
      // Cast into source string, will do for our purposes.
      $source = new SourceString($string);
      // Split source to work with plural values.
      $source_array = $source->getPlurals();
      $translation_array = $string->getPlurals();
      if (count($source_array) == 1) {
        // Add original string value and mark as non-plural.
        $plural = FALSE;
        $form['strings'][$string->lid]['original'] = array(
          '#type' => 'item',
          '#title' => $this->t('Source string (@language)', array('@language' => $this->t('Built-in English'))),
          '#title_display' => 'invisible',
          '#plain_text' => $source_array[0],
          '#preffix' => '<span lang="en">',
          '#suffix' => '</span>',
        );
      }
      else {
        // Add original string value and mark as plural.
        $plural = TRUE;
        $original_singular = [
          '#type' => 'item',
          '#title' => $this->t('Singular form'),
          '#plain_text' => $source_array[0],
          '#prefix' => '<span class="visually-hidden">' . $this->t('Source string (@language)', array('@language' => $this->t('Built-in English'))) . '</span><span lang="en">',
          '#suffix' => '</span>',
        ];
        $original_plural = [
          '#type' => 'item',
          '#title' => $this->t('Plural form'),
          '#plain_text' => $source_array[1],
          '#preffix' => '<span lang="en">',
          '#suffix' => '</span>',
        ];
        $form['strings'][$string->lid]['original'] = [
          $original_singular,
          ['#markup' => '<br>'],
          $original_plural,
        ];
      }
      if (!empty($string->context)) {
        $form['strings'][$string->lid]['original'][] = [
          '#type' => 'inline_template',
          '#template' => '<br><small>{{ context_title }}: <span lang="en">{{ context }}</span></small>',
          '#context' => [
            'context_title' => $this->t('In Context'),
            'context' => $string->context,
          ],
        ];
      }
      // Approximate the number of rows to use in the default textarea.
      $rows = min(ceil(str_word_count($source_array[0]) / 12), 10);
      if (!$plural) {
        $form['strings'][$string->lid]['translations'][0] = array(
          '#type' => 'textarea',
          '#title' => $this->t('Translated string (@language)', array('@language' => $langname)),
          '#title_display' => 'invisible',
          '#rows' => $rows,
          '#default_value' => $translation_array[0],
          '#attributes' => array('lang' => $langcode),
        );
      }
      else {
        // Add a textarea for each plural variant.
        for ($i = 0; $i < $plurals; $i++) {
          $form['strings'][$string->lid]['translations'][$i] = array(
            '#type' => 'textarea',
            // @todo Should use better labels https://www.drupal.org/node/2499639
            '#title' => ($i == 0 ? $this->t('Singular form') : $this->formatPlural($i, 'First plural form', '@count. plural form')),
            '#rows' => $rows,
            '#default_value' => isset($translation_array[$i]) ? $translation_array[$i] : '',
            '#attributes' => array('lang' => $langcode),
            '#prefix' => $i == 0 ? ('<span class="visually-hidden">' . $this->t('Translated string (@language)', array('@language' => $langname)) . '</span>') : '',
          );
        }
        if ($plurals == 2) {
          // Simplify interface text for the most common case.
          $form['strings'][$string->lid]['translations'][1]['#title'] = $this->t('Plural form');
        }
      }
    }
    if (count(Element::children($form['strings']))) {
      $form['actions'] = array('#type' => 'actions');
      $form['actions']['submit'] = array(
        '#type' => 'submit',
        '#value' => $this->t('Save translations'),
      );
    }
  }
  $form['pager']['#type'] = 'pager';
  return $form;
}