addContextAssignmentElement example

return !empty($this->configuration['negate']);
  }

  /** * {@inheritdoc} */
  public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
    if ($form_state instanceof SubformStateInterface) {
      $form_state = $form_state->getCompleteFormState();
    }
    $contexts = $form_state->getTemporaryValue('gathered_contexts') ?: [];
    $form['context_mapping'] = $this->addContextAssignmentElement($this, $contexts);
    $form['negate'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('Negate the condition'),
      '#default_value' => $this->configuration['negate'],
    ];
    return $form;
  }

  /** * {@inheritdoc} */
  

/** * {@inheritdoc} */
  public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
    $form['label'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Administrative label'),
      '#default_value' => $this->configuration['label'],
    ];
    $contexts = $form_state->getTemporaryValue('gathered_contexts') ?: [];
    $form['context_mapping'] = $this->addContextAssignmentElement($this, $contexts);
    return $form;
  }

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

  /** * {@inheritdoc} */

use ContextAwarePluginTrait;
  use ContextAwarePluginAssignmentTrait;

  /** * {@inheritdoc} */
  public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
    $form = $this->traitBuildConfigurationForm($form, $form_state);

    // Add context mapping UI form elements.     $contexts = $form_state->getTemporaryValue('gathered_contexts') ?: [];
    $form['context_mapping'] = $this->addContextAssignmentElement($this, $contexts);

    return $form;
  }

}