You know that list of checkboxes on the theme settings page that let you turn on and off parts of the theme like the logo or slogan? Well, you can add your own options to that list really easily in Drupal 7. In D6, this was kind of a pain, because you had to write all sorts of functions to save and load your settings to the database and handle everything properly. In D7, that’s all done through the Form API, so the heavy lifting is done for you. All you need to do is tell it to add some form fields, and what the new setting is called!

You’ll need to create a theme-settings.php file in your theme, and add this code to it:

<?php
function themename_form_system_theme_settings_alter(&$form, &$form_state) {
  $form['theme_settings']['your_option'] = array(
    '#type' => 'checkbox',
    '#title' => t('Your Option'),
    '#default_value' => theme_get_setting('your_option'),
  );
}

• ['theme_settings'] is the existing fieldset to add your option to. You can leave it off, but by pointing it to the theme_settings group, it’ll be added to the existing list of checkbox display options for your theme. Handy!
• ['your_option'] is the name of your new option.
• #type tells Drupal what kind of form element to create.
• #title is the title (or in this case, label) text for the form element.
• #default_value tells Drupal where to find the initial setting for the form element.

We set #default_value to theme_get_setting('your_option'), which tells Drupal to look for this setting in the database. But here’s the brilliant part — if it can’t find that setting in the database, it will check in your theme’s .info file! So add this line:

settings[your_option] = 1

Now your theme will use the default setting unless the admin overrides it on the theme settings page.

You’ll want to actually do something with this setting, so here’s the PHP call to load it.

theme_get_setting('your_option');

You can call this in from any of your .tpl.php files. For a simple checkbox option like this, you can build an if() statement around it, like so:

<?php if (theme_get_setting('your_option')): ?>
  <!-- Your code here! -->
<?php endif; ?>

In this example, we added a checkbox, but you can add just about any form elements you can think of, including radio buttons and text input fields. What sort of options will you add to your theme?

References

• theme_get_setting() and THEME_settings() improvements in Drupal 7
• Drupal 7 form API reference
• Advanced theme settings – this is for D6, but it’s still helpful