Enable/disable a menu item programatically depending on a variable value

Question

I need to show a menu item only in certain moments. Imagine that I've a form with some options. If 'A' is selected, I need to enable a menu item that has a form for adding information about 'A'.

I have done a module that has a hook_menu like this:

> function secciones_menu() {
>   
> 
>   $items = array();
> 
>       $items['secciones'] = array(
>           'title' => t('Crear Sección'),
>           'description' => t('Crear Secciones'),
>           'page callback' => 'drupal_get_form',
>           'page arguments' => array('secciones_wizard'),
>           'access callback' = TRUE,
>           'type' => MENU_NORMAL_ITEM,
>           'menu_name' => 'main-menu',         'customized' => 1, // Must be 1 in order to not dispaly the link in any language
>           'language'  => 'es', // language is required in order to make the item translatable   );  

return $items; }

And then have my form for 'A'. So how I can enable or disable the menu item, depending a variable value?

Thank you !

EDIT 1:

What I've done is change the access callback and the menu type:

function agenda_menu() {


  $items = array();


  $items['agenda'] = array(
        'title' => t('4. Crear agenda'),
        'description' => t('Crear agenda'),
        'parent'=>array('Configurar Revista'),
        'page callback' => 'drupal_get_form',
        'page arguments' => array('agenda_wizard'),
        'access callback' => 'agenda_access_callback',
        'type' => MENU_DEFAULT_LOCAL_TASK,
        'menu_name' => 'main-menu',
        'customized' => 1, // Must be 1 in order to not dispaly the link in any language
            'language'  => 'es', // language is required in order to make the item translatable
  );


  return $items;
}

And then I've done the next code:

function agenda_access_callback(){

    //db query
    //insert that query in $options array
    foreach ($result as $row) {
        $options[$row->id_seccion] = $row->id_seccion;
    }

    if(isset($options)){ //if the array is not empty
        return TRUE; //the menu item is visible
    }
    else{
        return FALSE; //otherwise, is not visible
    }
}

Ok, this is what I have done, but it doesn't work. Any idea? Thank you.

Answer 1

The usual way to enable a menu item only in certain circumstances is to use a custom access callback, in which you would evaluate whether this option is set. So:

'access callback' = 'my_module_access_callback',
...

function my_module_access_callback() {
   return my_module_test_option_is_true();
}

But it's a little hard to be sure if this will work for your case as you haven't given us much to go on.