How do I add a checkbox to the performance page and have it repopulate?

Question

I would like to add a checkbox of my own to the performance page in the Drupal administration. I am using hook_form_alter like this:

function nci_assay_depot_form_alter(&$form, &$form_state, $form_id){
    switch($form_id){
        case "system_performance_settings":
            $form["caching"]["nci_assay_depot"] = array(
                "#type" => "checkbox"
                ,"#title" => "Refresh Assay Depot Cache when 'Clear All Caches'"
                ,"#default_value" => 1
                ,"#disabled" => 0
                ,"#description" => null
                ,"#weight" => -2
            ) ;
        break;
    }
}

It will display on the page, but the value will not be saved. Any thoughts?

Answer 1

• to have it "repopulate" after save provide a #default_value key that retrieves it on page load.
• to actually save it append (add another) custom form submit handler to the form, after the original one gets fired. Something like $form['#submit'][] = 'mymodule_mysubmit_handler'; You will have to check where the submit handler is set already in the form, or the element you're trying to hook into (such as $form['caching'] ...