WP Mobile Detector

gistfile1.php

<?php
/*
Plugin Name: Theme Mobile Detector
Version: 1.0
*/

# Replace all occurrences of "theme" with your theme name

if (get_option('template') == 'theme') {
	if (!session_id()) session_start();
	
	if (isset($_GET['desktop']) && $_GET['desktop'] == 1) {
		unset($_SESSION['mobile']);
		$_SESSION['desktop'] = 1;
	}
	
	if (isset($_GET['mobile'])) {
		unset($_SESSION['desktop']);
		$_SESSION['mobile'] = 1;
	}
	
	if (!isset($_SESSION['desktop']) || $_SESSION['desktop'] != 1) {
		$iphone = preg_match('~iphone~iu', $_SERVER['HTTP_USER_AGENT']);
		$ipod = preg_match('~ipod~iu', $_SERVER['HTTP_USER_AGENT']);
		
		$android = preg_match('~android~iu', $_SERVER['HTTP_USER_AGENT']);
		$android_tablet = $android;
		if ($android) {
			$android_phone = preg_match('~mobile~iu', $_SERVER['HTTP_USER_AGENT']);
			$android_tablet = !$android_phone;
		}
		
		$blackberry = preg_match('~blackberry~iu', $_SERVER['HTTP_USER_AGENT']);
		$palm = preg_match('~palm~iu', $_SERVER['HTTP_USER_AGENT']);
		$iemobile = preg_match('~iemobile~iu', $_SERVER['HTTP_USER_AGENT']);
		$zunewp7 = preg_match('~zunewp7~iu', $_SERVER['HTTP_USER_AGENT']);
		
		if (!is_admin()) {
			if ($iphone || $ipod || $android_phone || $blackberry || $palm || $iemobile || $zunewp7 || isset($_SESSION['mobile'])) {
				define('THEME_MOBILE', true);
				add_filter('stylesheet', create_function('', 'return "theme-mobile";'));
				// add_filter('template', create_function('', 'return "theme";')); # Comment out if mobile theme is child of desktop theme
			} else {
				define('THEME_MOBILE', false);
			}
		}
	}
}
?>