Wordpress Plugin not loading CSS on the plugin's option page in the admin menu

Question

I'm building a WordPress plugin, but I'm having trouble loading the css on the plugin's options page in the admin menu. I consulted the codex at http://codex.wordpress.org/Function_Reference/wp_enqueue_style

And here's what I got (I simplified the code by taking out all the parts irrelevant to my question and changing the plugin name):

<?php

if (!class_exists('My_Plugin')){
    class My_Plugin{

        public function __construct(){

            //add admin page
            add_action('admin_menu', array($this, 'my_plugin_menu'));
            add_action('admin_init', array($this, 'my_admin_init'));
        }

        //adds a page in the admin menu under posts
        public function my_admin(){

            //ensure user is admin
            if ( !current_user_can( 'manage_options' ) )  {
                wp_die( __( 'You do not have sufficient permissions to access this page.' ) );
            }
            ?>
            <div class="wrap">
            <?php screen_icon(); ?>
            <h1>My Plugin</h1>
            </div>
            <?php
        }

        //admin initialization function
        public function my_admin_init(){
            //register admin page's css
            wp_register_style('my_style', plugins_url('my_style.css', __FILE__));
        }

        //add css files for admin menu()
        public function my_admin_enqueue_styles(){
            wp_enqueue_style('my_style');
        }

        //add menu page under posts
        public function my_plugin_menu(){
            $page = add_submenu_page('edit.php', 'My Plugin', 'My Plugin', 'manage_options', 'my-plugin', array($this, 'my_admin'));
            //add css
            add_action('admin_print_styles-'.$page, 'my_admin_enqueue_styles');
        }
    }

    //instantiate the class
    $mp = new My_Plugin();
}

In the my_style.css file I just stuck h1{color:red;} in order to test it out. The options page loads fine, but firebug isn't showing the css as being loaded at all. I'm stumped. What do I need to do?

am i right to say this has nothing to do with css? atleast the [css] tag — iConnor

Chris Chris · Accepted Answer · 2013-06-06T21:34:03

Figured it out... It was the line:

add_action('admin_print_styles-'.$page, 'my_admin_enqueue_styles');

Since I'm doing all this inside a class, I need to pass the second parameter as an array with $this

add_action('admin_print_styles-'.$page, array($this, 'my_admin_enqueue_styles'));

I did it with the other hooks, just missed this since it's not done that way in the codex. Silly me.

Wordpress Plugin not loading CSS on the plugin's option page in the admin menu

1 Answers