public function AjaxAddRemoveElements::buildForm in Examples for Developers 3.x

Form with 'add more' and 'remove' buttons.

Overrides FormInterface::buildForm

File

modules/form_api_example/src/Form/AjaxAddRemoveElements.php, line 26

Class

AjaxAddRemoveElements

Example ajax add remove buttons.

Namespace

Drupal\form_api_example\Form

Code

public function buildForm(array $form, FormStateInterface $form_state) {
  $form['description'] = [
    '#type' => 'item',
    '#markup' => $this
      ->t('This example shows an add-more button and a remove button for each specific element.'),
  ];

  // Get the number of names in the form already.
  $num_lines = $form_state
    ->get('num_lines');

  // We have to ensure that there is at least one name field.
  if ($num_lines === NULL) {
    $form_state
      ->set('num_lines', 1);
    $num_lines = $form_state
      ->get('num_lines');
  }

  // Get a list of fields that were removed.
  $removed_fields = $form_state
    ->get('removed_fields');

  // If no fields have been removed yet we use an empty array.
  if ($removed_fields === NULL) {
    $form_state
      ->set('removed_fields', []);
    $removed_fields = $form_state
      ->get('removed_fields');
  }
  $form['#tree'] = TRUE;
  $form['names_fieldset'] = [
    '#type' => 'fieldset',
    '#title' => $this
      ->t('People coming to picnic'),
    '#prefix' => '<div id="names-fieldset-wrapper">',
    '#suffix' => '</div>',
  ];
  for ($i = 0; $i < $num_lines; $i++) {

    // Check if field was removed.
    if (in_array($i, $removed_fields)) {

      // Skip if field was removed and move to the next field.
      continue;
    }

    /* Create a new fieldset for each person
     * where we can add first and last name
     */

    // Fieldset title.
    $form['names_fieldset'][$i] = [
      '#type' => 'fieldset',
      '#title' => $this
        ->t('Person') . ' ' . ($i + 1),
    ];

    // Date.
    $form['names_fieldset'][$i]['firstname'] = [
      '#type' => 'textfield',
      '#title' => $this
        ->t('First name'),
    ];

    // Amount.
    $form['names_fieldset'][$i]['lastname'] = [
      '#type' => 'textfield',
      '#title' => $this
        ->t('Last name'),
    ];
    $form['names_fieldset'][$i]['actions'] = [
      '#type' => 'submit',
      '#value' => $this
        ->t('Remove'),
      '#name' => $i,
      '#submit' => [
        '::removeCallback',
      ],
      '#ajax' => [
        'callback' => '::addmoreCallback',
        'wrapper' => 'names-fieldset-wrapper',
      ],
    ];
  }
  $form['names_fieldset']['actions'] = [
    '#type' => 'actions',
  ];
  $form['names_fieldset']['actions']['add_name'] = [
    '#type' => 'submit',
    '#value' => $this
      ->t('Add one more'),
    '#submit' => [
      '::addOne',
    ],
    '#ajax' => [
      'callback' => '::addmoreCallback',
      'wrapper' => 'names-fieldset-wrapper',
    ],
  ];
  $form['actions']['submit'] = [
    '#type' => 'submit',
    '#value' => $this
      ->t('Submit'),
  ];
  return $form;
}