Taxonomy tags are not saved - Field API - Drupal 7

Question

I am creating a new content type and I want to add a Tags field. I created a vocabulary and a taxonomy_term_reference, field but this field is giving this notice every time I try to add content and click save:

Notice: Undefined index: tid in taxonomy_field_is_empty() (line 1562 of /var/www/html/drupal/modules/taxonomy/taxonomy.module).

This is the code I am using.

news.install

function news_install() {
  node_types_rebuild();
  $types = node_type_get_types();
  // Add the body field to the node type
  node_add_body_field($types['news']);

  // Load the instance definition for our content type's body
  $body_instance = field_info_instance('node', 'body', 'news');
  // Configure the body field
  $body_instance['type'] = 'text_summary_or_trimmed';
  // Save our changes to the body field instance.
  field_update_instance($body_instance);
  // Create all the fields we are adding to our content type.
  foreach (_news_installed_fields() as $field) {
    field_create_field($field);
  }


  // Create all the instances for our fields.
  foreach (_news_installed_instances() as $instance) {
    $instance['entity_type'] = 'node';
    $instance['bundle'] = 'news';
    $instance['required'] = True;
    field_create_instance($instance);
  }

  // Create vocabulary for tags
  $news_tags_vocab = (object) array(
    'name' => 'Tags vocabulary',
    'description' => 'This vocabulary is used for the tags field',
    'machine_name' => 'news_tags_vocab',
    );

  taxonomy_vocabulary_save($news_tags_vocab);
}

function _news_installed_fields() {
  $t = get_t();
  return array(
    'news_title' => array(
      'field_name' => 'news_title',
      'label' => $t('Title'),
      'type' => 'text',
      ),
    'news_image' => array(
      'field_name' => 'news_image',
      'label' => $t('Image'),
      'type' => 'image',
    ),
    'news_tags' => array(
      'field_name' => 'news_tags',
      'label' => $t('Add Tags'),
      'type' => 'taxonomy_term_reference',
      'settings' => array(
        'allowed_values' => array(
          array(
            'vocabulary' => 'news_tags_vocab',
            'parent' => 0,
            ),
          ),
        ),
      ),
    ),
  );
}

/**
 * Return a structured array defining the field instances associated with this content type.
 */
function _news_installed_instances() {
  $t = get_t();
  return array(
    'news_title' => array(
      'field_name' => 'news_title',
      'type' => 'text',
      'label' => $t('The heading of the news topic'),
      'widget' => array(
        'type' => 'text_textfield',
      ),
      'display' => array(
        'news_display_option' => array(
          'label' => $t('The heading of the news topic (display option)'),
          'type' => 'text',
          ),
        ),
      ),
      'news_image' => array(
        'field_name' => 'news_image',
        'type' => 'image',
        'label' => $t('Add Image'),
      ),
      'news_tags' => array(
        'field_name' => 'news_tags',
        'type' => 'taxonomy_term_reference',
        'label' => $t('Add Tags'),
        'widget' => array(
          'type' => 'taxonomy_autocomplete'
        ),
        'display' => array(
          'default' => array('type' => 'hidden'),
          'teaser' => array('type' => 'hidden')
        ),
      ),
    )
  );
}

/**
 * Implements hook_uninstall().
 */
function news_uninstall() {
  // Delete the taxonomy with its terms
  $vocab = taxonomy_vocabulary_machine_name_load('news_tags_vocab');
  taxonomy_vocabulary_delete($vocab->vid);

  // Gather all the example content that might have been created while this
  // module was enabled.
  $sql = 'SELECT nid FROM {node} n WHERE n.type = :type';
  $result = db_query($sql, array(':type' => 'news'));
  $nids = array();
  foreach ($result as $row) {
    $nids[] = $row->nid;
  }

  // Delete all the nodes at once
  node_delete_multiple($nids);
  // Loop over each of the fields defined by this module and delete
  // all instances of the field, their data, and the field itself.
  foreach (array_keys(_news_installed_fields()) as $field) {
    field_delete_field($field);
  }
  // Loop over any remaining field instances attached to the news
  // content type (such as the body field) and delete them individually.
  $instances = field_info_instances('node', 'news');
  foreach ($instances as $instance_name => $instance) {
    field_delete_instance($instance);
  }
  // Delete our content type
  node_type_delete('news');
  // Purge all field infromation
  field_purge_batch(1000);
}

What's wrong in my code, and how can I fix it?

Answer 1

The solution for this problem is to implement Hook_form() So, the following code must be added into news.module file.

function news_form($node, $form_state){
  return node_content_form($node, $form_state);
}

Tricky but easy :)