Custom Field Type only shows -hidden- Widget
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';
}