Custom Field Type only shows -hidden- Widget I want to create a Field Type with text_textfield as default widget.
But all I get is -hidden-

Here is my FieldType Class

&lt;?php

namespace Drupal\gettweet\Plugin\Field\FieldType;

use Drupal\Component\Utility\Random;
use Drupal\Core\Field\FieldDefinitionInterface;
use Drupal\Core\Field\FieldItemBase;
use Drupal\Core\Field\FieldStorageDefinitionInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\Core\TypedData\DataDefinition;

/**
 * Plugin implementation of the 'get_tweet_field_type' field type.
 *
 * @FieldType(
 *   id = "get_tweet_field_type",
 *   label = @Translation("Get tweet"),
 *   description = @Translation("Reference a tweet token"),
 *   default_widget = "text_textfield",
 *   default_formatter = "text_default"
 * )
 */
class GetTweetFieldType extends FieldItemBase {

  /**
   * {@inheritdoc}
   */
  public static function defaultStorageSettings() {
    return [
      'max_length' =&gt; 255,
      'is_ascii' =&gt; FALSE,
      'case_sensitive' =&gt; FALSE,
    ] + parent::defaultStorageSettings();
  }

  /**
   * {@inheritdoc}
   */
  public static function propertyDefinitions(FieldStorageDefinitionInterface $field_definition) {
    // Prevent early t() calls by using the TranslatableMarkup.
    $properties['value'] = DataDefinition::create('string')
      -&gt;setLabel(new TranslatableMarkup('Text value'))
      -&gt;setSetting('case_sensitive', $field_definition-&gt;getSetting('case_sensitive'))
      -&gt;setRequired(TRUE);

    return $properties;
  }

  /**
   * {@inheritdoc}
   */
  public static function schema(FieldStorageDefinitionInterface $field_definition) {
    $schema = [
      'columns' =&gt; [
        'value' =&gt; [
          'type' =&gt; $field_definition-&gt;getSetting('is_ascii') === TRUE ? 'varchar_ascii' : 'varchar',
          'length' =&gt; (int) $field_definition-&gt;getSetting('max_length'),
          'binary' =&gt; $field_definition-&gt;getSetting('case_sensitive'),
        ],
      ],
    ];

    return $schema;
  }

  /**
   * {@inheritdoc}
   */
  public function getConstraints() {
    $constraints = parent::getConstraints();

    if ($max_length = $this-&gt;getSetting('max_length')) {
      $constraint_manager = \Drupal::typedDataManager()-&gt;getValidationConstraintManager();
      $constraints[] = $constraint_manager-&gt;create('ComplexData', [
        'value' =&gt; [
          'Length' =&gt; [
            'max' =&gt; $max_length,
            'maxMessage' =&gt; t('%name: may not be longer than @max characters.', [
              '%name' =&gt; $this-&gt;getFieldDefinition()-&gt;getLabel(),
              '@max' =&gt; $max_length
            ]),
          ],
        ],
      ]);
    }

    return $constraints;
  }

  /**
   * {@inheritdoc}
   */
  public static function generateSampleValue(FieldDefinitionInterface $field_definition) {
    $random = new Random();
    $values['value'] = $random-&gt;word(mt_rand(1, $field_definition-&gt;getSetting('max_length')));
    return $values;
  }

  /**
   * {@inheritdoc}
   */
  public function storageSettingsForm(array &amp;$form, FormStateInterface $form_state, $has_data) {
    $elements = [];

    $elements['max_length'] = [
      '#type' =&gt; 'number',
      '#title' =&gt; t('Maximum length'),
      '#default_value' =&gt; $this-&gt;getSetting('max_length'),
      '#required' =&gt; TRUE,
      '#description' =&gt; t('The maximum length of the field in characters.'),
      '#min' =&gt; 1,
      '#disabled' =&gt; $has_data,
    ];

    return $elements;
  }

  /**
   * {@inheritdoc}
   */
  public function isEmpty() {
    $value = $this-&gt;get('value')-&gt;getValue();
    return $value === NULL || $value === '';
  }

}
If you are absolutely sure your field type is compatible with some existing widgets and formatters you can reuse them by implementing hook_field_widget_info_alter and hook_field_formatter_info_alter.

/**
 * Implements hook_field_widget_info_alter().
 */
function gettweet_field_widget_info_alter(array &amp;$info) {
  $info['text_textfield']['field_types'][] = 'get_tweet_field_type';
}

/**
 * Implements hook_field_formatter_info_alter().
 */
function gettweet_field_formatter_info_alter(array &amp;$info) {
  $info['text_default']['field_types'][] = 'get_tweet_field_type';
}