Save and Retrieve Admin Settings from the database

Question

I created a config form in the admin/config page. (Just a link field that needs to be saved for later retrieval) Im confused as to how to save and retrieve the form data.

When creating a custom form in a block I have been successful using:

variable_get('link_title', '')

However when creating a custom form it seems to require a different way. I attempted to save the data in hook_form_submit. However Im not sure how to retrieve when you return to the form at a later date.

function read_more_news_admin_form($form, &$form_state) {
        $form = array();
        $form['link_container'] = array(
            '#type' => 'container',
            '#attributes' => array('class' => array('some-class')),
            '#tree' => TRUE,
        );
        $form['link_container']['link'] = array(
            '#type' => 'link_field',
            '#field_name' => 'link_field',
            '#language' => 'und',
            '#field_parents' => array(),
            '#delta' => 0,
            '#default_value' => array(
                'title' => variable_get('link_title', ''),
                'url' => variable_get('link_url', ''),
            ),
        );
        return system_settings_form($form);
    }

    function read_more_news_form_submit($form_id, $form_values) {
      drupal_write_record('readmorelink', $form_state['values']); 
    }

Answer 1

I don't know how system_settings_form will handle form elements of which the parent element has the tree property set. So it is best to go with a submit handler and do it yourself.

function read_more_news_admin_form($form, &$form_state) {
  $form = array();
  $form['link_container'] = array(
    '#type' => 'container',
    '#attributes' => array('class' => array('some-class')),
    '#tree' => TRUE,
  );
  $form['link_container']['link'] = array(
    '#type' => 'link_field',
    '#field_name' => 'link_field',
    '#language' => 'und',
    '#field_parents' => array(),
    '#delta' => 0,
    '#default_value' => array(
      'title' => variable_get('link_title', ''),
      'url' => variable_get('link_url', ''),
    ),
  );
  $form['submit'] = array('#type' => 'submit', '#value' => t('Submit'));
  return $form;
}

function read_more_news_admin_form_submit(&$form, &$form_state) {
  variable_set('link_title', $form_state['values']['link_container']['link']['title']);
  variable_set('link_url', $form_state['values']['link_container']['link']['url']);
  //drupal_write_record('readmorelink', $form_state['values']);
}

Answer 2

You don't need to use a separate submit handler if you are using system_settings_form() unless you need to do something out of the ordinary.

Setting the #default_value of each element with variable_get will retain the settings of your form. variable_get will check if the variable exists and use the stored variable if there is one, otherwise it will use the 2nd argument in the call.

A basic working example would be like this:

function HOOK_admin_form($node, &$form_state) {
  $form['MODULE_ELEMENT'] = array(
    '#type' => 'textfield',
    '#default_value' => variable_get('MODULE_ELEMENT', 'value'),
    '#title' => t('title'),
    '#required' => TRUE,
  );

  $form['MODULE_ELEMENT2'] = array(
    '#type' => 'textfield',
    '#default_value' => variable_get('MODULE_ELEMENT2', 'value'),
    '#title' => t('title'),
    '#required' => TRUE,
  );

  return system_settings_form($form);
}