--- /dev/null
+<?php
+
+namespace Drupal\{{ machine_name }}\Form;
+
+use Drupal\Core\Form\ConfigFormBase;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Configure {{ name }} settings for this site.
+ */
+class {{ class }} extends ConfigFormBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getFormId() {
+ return '{{ form_id }}';
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function getEditableConfigNames() {
+ return ['{{ machine_name }}.settings'];
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function buildForm(array $form, FormStateInterface $form_state) {
+ $form['example'] = [
+ '#type' => 'textfield',
+ '#title' => $this->t('Example'),
+ '#default_value' => $this->config('{{ machine_name }}.settings')->get('example'),
+ ];
+ return parent::buildForm($form, $form_state);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function validateForm(array &$form, FormStateInterface $form_state) {
+ if ($form_state->getValue('example') != 'example') {
+ $form_state->setErrorByName('example', $this->t('The value is not correct.'));
+ }
+ parent::validateForm($form, $form_state);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function submitForm(array &$form, FormStateInterface $form_state) {
+ $this->config('{{ machine_name }}.settings')
+ ->set('example', $form_state->getValue('example'))
+ ->save();
+ parent::submitForm($form, $form_state);
+ }
+
+}