ConfirmFormBase to FormBase

Question

Drupal 8.7.x

I have a Form button with a confirmation page to delete an ingredient. I'm trying to convert it to a standard Form that just deletes it without confirmation, however I keep getting an error.

Confirmation Form (works just fine) src/Form/DeleteIngredient.php:

 <?php

namespace Drupal\recipe_search\Form;

use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Form\ConfirmFormBase;
use Drupal\Core\Url;

/**
 * Class DeleteIngredient
 *
 * @package Drupal\recipe_search\Form
 */
class DeleteIngredient extends ConfirmFormBase{

  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'delete_ingredient';
  }

  public $cid;

  public function getQuestion() {
    return t('Do you want to delete %cid?', array('%cid' => $this->cid));
  }

  public function getCancelUrl() {
    return new Url('recipe_search.recipes');
  }

  public function getDescription() {
    return t('Only do this if you are sure!');
  }
  /**
   * {@inheritdoc}
   */
  public function getConfirmText() {
    return t('Delete it!');
  }
  /**
   * {@inheritdoc}
   */
  public function getCancelText() {
    return t('Cancel');
  }

  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state, $cid = NULL) {
    $this->pid = $cid;
    return parent::buildForm($form, $form_state);
  }

  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {

    $database = \Drupal::database();
    $database->delete('ingredient_list')
      ->condition('pid', $this->pid)
      ->execute();

    $form_state->setRedirect('recipe_search.recipes');

  }

Tried this for normal form without confirmation src/Form/DeleteIngredient.php:

<?php

namespace Drupal\recipe_search\Form;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;

/**
 * Class DeleteIngredient
 *
 * @package Drupal\recipe_search\Form
 */
class DeleteIngredient extends FormBase{

  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'delete_ingredient';
  }

  public $cid;

  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state, $cid = NULL) {
    $this->pid = $cid;
    return parent::buildForm($form, $form_state);
  }

  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {

    $database = \Drupal::database();
    $database->delete('ingredient_list')
      ->condition('pid', $this->pid)
      ->execute();

    $form_state->setRedirect('recipe_search.recipes');

  }
}

This is where I return the form to the twig template src/Block/RecipeSearch.php:

//FETCH THE INGREDIENTS TO MAKE AN API CALL
$result = $connection->select('ingredient_list', 'il');
$result->fields('il', array('ingredient', 'pid'));
$result->condition('uid', $uid);
$data = $result->execute();
$results = $data->fetchAll(\PDO::FETCH_OBJ);

foreach ($results as $field) {
  $delete = Url::fromUserInput('/delete/'.$field->pid);

  array_push($ingredients, ["ingredient" => $field->ingredient, "delete" => $delete]);
  array_push($ingredientsArray, $field->ingredient);
}; 

This is the Error I'm getting:

Error: Cannot call abstract method Drupal\Core\Form\FormInterface::buildForm() in Drupal\recipe_search\Form\DeleteIngredient->buildForm() (line 32 of /var/www/html/web/modules/custom/recipe_search/src/Form/DeleteIngredient.php)

I guess you cannot use buildForm while extending FormBase but I don't know how I should solve this.

Thanks in advance!

Answer 1

There is no FormBase::buildForm() method. FormBase implements FormStateInterface, and the method FormStateInterface::buildForm() exists. So when you extend FormBase, you must implement buildForm(), however you do not/cannot call parent::buildForm(). Instead, you must build the form array yourself, and return that.

This differs from ConfirmForm which has a buildForm() method, which is why when you extend ConfirmForm you can call parent::buildForm().