How can I limit a wordpress meta_box to a single page?

Question

I need a way to limit the meta box to a single page (ID=84) ... if I do the following it works, but sbumit data does not go through and data is not saved ...

add_action('admin_init','violin_init');

function violin_init()
{
    if ($_GET['post'] == '84')
    {
        wp_enqueue_style('violin_admin_css', VIOLIN_THEME_PATH . '/custom/meta.css');

        add_meta_box('violin_options_meta', 'Highlight Content', 'violin_options_meta', 'page', 'normal', 'high');

        add_action('save_post','violin_save_meta');
    }
}

Answer 1

I've found a solution that works, but I wish there was a way through the wordpress API and/or one of wordpress' globals ...

the following works:

if ($_GET['post'] == '84' OR $_REQUEST['post_ID'] == '84')

Additionally you can also filter by a specific template:

$post_id = $_GET['post'] ? $_GET['post'] : $_POST['post_ID'] ;

$template_file = get_post_meta($post_id,'_wp_page_template',TRUE);

if ($template_file == 'home.php') {} // by template file

if ($post_id == 84) {} // by page ID

I wrote a blog post on it: Page Specific WordPress Meta Box