Drupal7: Field Node Entity Beispiel (Example / Kickstarter) Module

/**
 * Implements hook_field_schema().
 */
function snip_field_schema($field) {
 
 $columns = array();
 
 if ($field['type'] == 'cssfield') {
  $columns = array(
    'columns' => array(
      'css' => array(
        'type' => 'text',
        'size' => 'big',
        'not null' => FALSE,
      ),
    ),
  );
 }
 
 if ($field['type'] == 'htmlfield') {
  $columns = array(
    'columns' => array(
      'html' => array(
        'type' => 'text',
        'size' => 'big',
        'not null' => FALSE,
      ),
    ),
  );
 }
 
 return $columns;
}

/**
 * Implements hook_theme().
 */
function snip_theme() {
 return array(
   'snip_formatter_snip_formatter_css' => array(
     'render element' => 'element',
   ),
   'snip_formatter_snip_formatter_html' => array(
     'render element' => 'element',
   ),
 );
}
 
/**
 * Implementation of hook_field_info().
 * 
 * Our main field, same key as in "module".install file
 */
function snip_field_info() {
 return array(
   'cssfield' => array(
     'label' => t('CSS Field'),
     'description' => t('Snipper'),
     'default_widget' => 'snip_widget_css',
     'default_formatter' => 'snip_formatter_css',
   ),
   'htmlfield' => array(
     'label' => t('HTML Field'),
     'description' => t('snip'),
     'default_widget' => 'snip_widget_html',
     'default_formatter' => 'snip_formatter_html',
   ),
 );
}
 
/**
 * Implements hook_field_formatter_info().
 * 
 * The main output handler. Map each formatter to a field
 * Rendering will run on hook_field_formatter_view()
 */
function snip_field_formatter_info() {
 return array(
   'snip_formatter_css' => array(
     'label' => 'Formatter: cssfield',
     'description' => 'Formatter: cssfield',
     'field types' => array('cssfield'),
   ),
   'snip_formatter_html' => array(
     'label' => 'Formatter: htmlfield',
     'description' => 'Formatter: htmlfield',
     'field types' => array('htmlfield'),
   ),
 );
}
 
/**
 * Implementation of hook_field_widget_info().
 * 
 * Main input / form for fields. We can provide diffrent forms here
 * Rendering will ron on hook_field_widget_form()
 */
function snip_field_widget_info() {
 return array(
   'snip_widget_css' => array(
     'label' => 'Widget: CSS',
     'field types' => array('cssfield'),
     #'multiple values' => FIELD_BEHAVIOR_DEFAULT,
   ),
   'snip_widget_html' => array(
     'label' => 'Widget: HTML',
     'field types' => array('htmlfield'),
     #'multiple values' => FIELD_BEHAVIOR_DEFAULT,
   ),
 );
}
 
 
/**
 * Implementation of hook_element_info().
 * 
 * You only need this hook if you need to filter widget types on hook_field_widget_form().
 * Use  #type as your array key and map a #process function to it
 * 
 */
function snip_element_info() {
 return array(
   'snip_widget_css' => array(
     '#input' => TRUE,
     '#process' => array('snip_cssfield_field_widget_form'),
   ),
   'snip_widget_html' => array(
     '#input' => TRUE,
     '#process' => array('snip_htmlfield_field_widget_form'),
   ),
 );
}
 
/**
 * Implements hook_field_widget_form().
 * 
 * You can also add field form directly here.
 * 
 * $element['css'] = array(
 *   '#type' => 'textfield',
 *   [...]
 * );
 * 
 * But if your module provides more than one widget for fields better use a hook_elements_info() wrapper named by #type
 * 
 * 
 */
function snip_field_widget_form(&$form, &$form_state, $field, $instance, $langcode, $items, $delta, $element) {
 
 $element += array(
   '#type' => $instance['widget']['type'],
   '#default_value' => isset($items[$delta]) ? $items[$delta] : '',
 );
 
  /* or without hook_elements_info()
   $element['css'] = array(
   '#type' => 'textfield',
   '#title' => t('css'),
   '#default_value' => isset($defaults['css']) ? $defaults['css'] : '',
   '#required' => $element['#required'],
   '#description' => t($field['description']),
   );
  */
 
 return $element;
}
 
/**
 * Implements hook_field_formatter_view().
 * 
 * Output all different output formatter on a theme function;
 * You can also use it without theme(); #markup is your friend
 * 
 */
function snip_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
 $elements = array();
 
 foreach ($items as $delta => $item) {
  $elements[$delta] = array(
    '#markup' => theme('snip_formatter_' . $display['type'], array('element' => $item, 'field' => $instance, 'entity' => $entity)),
  );
 }
 
 return $elements;
}
 
/**
 * Implemented on snip_element_info()
 * 
 * Our form additional form elements on node forms
 */
function snip_htmlfield_field_widget_form($element, $form_state, $complete_form) {
 
 $defaults = $element['#value'];
 $field = field_widget_instance($element, $form_state);
 
 $element['html'] = array(
   '#type' => 'textfield',
   '#title' => t('html'),
   '#default_value' => isset($defaults['html']) ? $defaults['html'] : '',
   '#required' => $element['#required'],
   '#description' => t($field['description']),
 );
 
 return $element;
}
 
/**
 * Implemented on snip_element_info()
 * 
 * Our form additional form elements on node forms
 */
function snip_cssfield_field_widget_form($element, $form_state, $complete_form) {
 
 $defaults = $element['#value'];
 $field = field_widget_instance($element, $form_state);
 
 $element['css'] = array(
   '#type' => 'textfield',
   '#title' => t('css'),
   '#default_value' => isset($defaults['css']) ? $defaults['css'] : '',
   '#required' => $element['#required'],
   '#description' => t($field['description']),
 );
 
 return $element;
}
 
 
/**
 * Implementation of hook_is_empty().
 * 
 * Give Drupal a chance to check if field is empty.
 * Hook is perform e.g. on node save form (not on rendering / viewing)
 * 
 */
function snip_field_is_empty($item, $field) {
 
 if ($field['type'] == 'cssfield') {
  return empty($item['css']);
 }
 
 if ($field['type'] == 'htmlfield') {
  return empty($item['html']);
 }
 
 return false;
}
 
/**
 * Define function in hook_theme() and call on hook_field_formatter_view()
 */
function theme_snip_formatter_snip_formatter_css($variables) {
 // notice: if you need the node object use $variables['entity']
 return $variables['element']['css'];
}
 
/**
 * Define function in hook_theme() and call on hook_field_formatter_view()
 */
function theme_snip_formatter_snip_formatter_html($variables) {
 return $variables['element']['html'];
}