break;
    case 'edit':
        // Edit an announcement.
        $announcement = SystemAnnouncementManager::get_announcement($_GET['id']);
        $values['id'] = $announcement->id;
        $values['title'] = $announcement->title;
        $values['content'] = $announcement->content;
        $values['start'] = api_get_local_time($announcement->date_start);
        $values['end'] = api_get_local_time($announcement->date_end);
        $values['range'] = substr(api_get_local_time($announcement->date_start), 0, 16) . ' / ' . substr(api_get_local_time($announcement->date_end), 0, 16);
        $values['visible_teacher'] = $announcement->visible_teacher;
        $values['visible_student'] = $announcement->visible_student;
        $values['visible_guest'] = $announcement->visible_guest;
        $values['lang'] = $announcement->lang;
        $values['action'] = 'edit';
        $groups = SystemAnnouncementManager::get_announcement_groups($announcement->id);
        $values['group'] = isset($groups['group_id']) ? $groups['group_id'] : 0;
        $action_todo = true;
        break;
}
if ($action_todo) {
    if (isset($_REQUEST['action']) && $_REQUEST['action'] == 'add') {
        $form_title = get_lang('AddNews');
        $url = api_get_self();
    } elseif (isset($_REQUEST['action']) && $_REQUEST['action'] == 'edit') {
        $form_title = get_lang('EditNews');
        $url = api_get_self() . '?id=' . intval($_GET['id']);
    }
    $form = new FormValidator('system_announcement', 'post', $url);
    $form->addElement('header', '', $form_title);
    $form->addText('title', get_lang('Title'), true);