function nodeapi_example_form_alter in Examples for Developers 6

Same name and namespace in other branches

1. 7 nodeapi_example/nodeapi_example.module \nodeapi_example_form_alter()

Implementation of hook_form_alter().

By implementing this hook, we're able to modify any form. We'll only make changes to two types: a node's content type configuration and edit forms.

We need to have a way for administrators to indicate which content types should have our rating field added. This is done by inserting a checkbox in the node's content type configuration page, in the 'Workflow' group.

Related topics

File

nodeapi_example/nodeapi_example.module, line 35

This is an example outlining how a module can be used to extend existing content types.

Code

function nodeapi_example_form_alter(&$form, $form_state, $form_id) {
  if ($form_id == 'node_type_form' && isset($form['identity']['type'])) {

    // Alter the node type's configuration form to add our setting. We don't
    // need to worry about saving this value back to the variable, the form
    // we're altering will do it for us.
    $form['workflow']['nodeapi_example'] = array(
      '#type' => 'radios',
      '#title' => t('NodeAPI Example Rating'),
      '#default_value' => variable_get('nodeapi_example_' . $form['#node_type']->type, 0),
      '#options' => array(
        0 => t('Disabled'),
        1 => t('Enabled'),
      ),
      '#description' => t('Should this node have a rating attached to it?'),
    );
  }
  elseif (isset($form['type']) && isset($form['#node']) && $form['type']['#value'] . '_node_form' == $form_id) {

    // If the rating is enabled for this node type, we insert our control
    // into the form.
    $node = $form['#node'];
    if (variable_get('nodeapi_example_' . $form['type']['#value'], 0)) {

      // Note that $form['nodeapi_example_rating'] will become
      // $node->nodeapi_example_rating in hook_nodeapi validate op
      // This also means that if there is a fieldgroup defined,
      // $form['group']['field'], that it will become $node->field.
      $form['nodeapi_example_rating'] = array(
        '#type' => 'select',
        '#title' => t('Rating'),
        '#default_value' => isset($node->nodeapi_example_rating) ? $node->nodeapi_example_rating : '',
        '#options' => array(
          0 => t('Unrated'),
          1,
          2,
          3,
          4,
          5,
        ),
        '#required' => TRUE,
        '#weight' => 0,
      );
    }
  }
}