Get Current Admin Screen Information In WordPress 3.3

There’re a couple of variables can help us determining which admin screen we’re seeing: $pagenow for current page ID, $typenow for current post type, etc. But using these variables requires us a huge afford to combine them just to get the correct information we want. Fortunately, since version 3.3, WordPress gives us a more completed solution with WP_Screen class which turns out the best way to get current admin screen information with ease of use.

Note: This topic is started by Kaiser at wp-hackers email list. I’m writing it here and add some notes for quick reference for myself and for others who interested.

To get the current screen object, simply use:

$screen = get_current_screen();

This $screen is an instance of WP_Screen class, which has the following interesting public variables:

Available public variables of current admin screen object

1. $screen->id: The unique ID of the screen.

2. $screen->base: The base type of the screen. This is typically the same as $screen->id but with any post types and taxonomies stripped.

For example, the base of post.php or post-new.php is post for all post types.

3. $screen->action: Any action associated with the screen.

• add for *-add.php and *-new.php screens.
• Empty otherwise.

4. $screen->is_network: Whether the screen is in the network admin.

5. $screen->is_user: Whether the screen is in the user admin.

6. $screen->parent_file: The parent file for the screen per the admin menu system.

Some $parent_file values are edit.php?post_type=page, edit.php, and options-general.php.

7. $screen->parent_base: The base menu parent.

This is derived from $parent_file by removing the query string and any .php extension.

For example, $parent_file values of edit.php?post_type=page and edit.php?post_type=post have a $parent_base of edit.

8. $screen->post_type: The post type associated with the screen, if any.

For example:

• The edit.php?post_type=page screen has a post type of page.
• The edit-tags.php?taxonomy=$taxonomy&post_type=page screen has a post type of page.

9. $screen->taxonomy: The taxonomy associated with the screen, if any.

For example, the edit-tags.php?taxonomy=category screen has a taxonomy of category.

Enqueue scripts and styles for editing custom post type page only

We’ll see an example of screen object to do a very popular thing in WordPress: enqueuing scripts and styles for admin pages.

WordPress gives us a hook wp_enqueue_scripts which has a parameter $hook_prefix to determine the current admin screen. But this parameter can’t give us information about the current post type unless we use another variable $typenow or check the $_GET.

But everything is now easier with screen object:

add_action( 'admin_enqueue_scripts', 'rw_enqueue_scripts' );

/**
 * Enqueue scripts and styles for editing page of 'slider' post type only
 *
 * @return void
 */
function rw_enqueue_scripts()
{
    $screen = get_current_screen();

    // Check screen base and current post type
    if ( 'post' === $screen->base && 'slider' === $screen->post_type )
    {
        wp_enqueue_script( 'slider-options', get_stylesheet_directory_uri() . '/js/slider-option.js', array( 'jquery' ) );
        // Enqueue other scripts and styles
    }
}