#WordPressPlugin: Switch admin color scheme via toolbar

admin-color-switch.php

<?php
/**
 * Plugin Name: Admin Color Switcher
 * Version: 0.1
 * Description: Switch admin color scheme via toolbar
 * Author: Dominik Schilling
 * Author URI: http://wphelper.de/
 * Plugin URI: http://wpgrafie.de/
 *
 *
 * License: GPLv2 or later
 *
 *	Copyright (C) 2013 Dominik Schilling
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version 2
 *	of the License, or (at your option) any later version.
 *
 *	This program is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License
 *	along with this program; if not, write to the Free Software
 *	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

/**
 * Don't call this file directly.
 */
if ( ! class_exists( 'WP' ) ) {
	die();
}

/**
 * The class which controls the plugin.
 *
 * Used hooks:
 *  - wp_before_admin_bar_render
 *
 * Inits at 'admin_init' hook.
 *
 */
class DS_Admin_Color_Switcher {

	/**
	 * A name for the change request
	 *
	 * @since  0.1
	 * @var    string
	 */
	static public $name = 'ds_switch_admin_color';

	/**
	 * Hooks into 'wp_before_admin_bar_render' to register toolbar items.
	 * Calls update_user_meta() when a change is requested.
	 *
	 * @since 0.1
	 */
	public static function init() {
		if ( isset( $_REQUEST[ self::$name ] ) )
			self::update_user_meta();

		add_action( 'wp_before_admin_bar_render', array( __CLASS__, 'admin_bar' ) );
	}

	/**
	 * Renders the toolbar items.
	 *
	 * @since  0.1
	 */
	public static function admin_bar() {
		global $wp_admin_bar, $_wp_admin_css_colors;

		// Get the current color
		$current_color = get_user_option( 'admin_color', get_current_user_id() );

		// Add parent item
		$wp_admin_bar->add_menu( array(
			'id'    => 'admin-color-scheme',
			'title' => $_wp_admin_css_colors[ $current_color ]->name,
			'href'  => '#'
		) );

		// Add sub items
		foreach ( $_wp_admin_css_colors as $color => $color_info ) {
			$title = $color_info->name;

			// Highlight current color
			if ( $color == $current_color )
				$title  = sprintf( '<strong>%s</strong>' , $color_info->name );

			$link = add_query_arg( self::$name, $color );

			$wp_admin_bar->add_menu( array(
				'parent' => 'admin-color-scheme',
				'id'     => 'admin-color-scheme-' . $color,
				'title'  => $title,
				'href'   => $link
			) );
		}
	}

	/**
	 * Updates the user meta.
	 *
	 * @since  0.1
	 */
	public static function update_user_meta() {
		update_user_meta(
			 get_current_user_id(),
			'admin_color',
			$_REQUEST[ self::$name ]
		);
	}
}

// Beam me up, Scotty.
add_action( 'admin_init', array( 'DS_Admin_Color_Switcher', 'init' ) );