Loads a template part incl. the appropriate stylesheet for desktop or mobile devices, based on custom conditional tags.

get_device_template.php

<?php
    /**
     * STYLESHEETS
     */
    	function print_device_styles( $client = 'desktop' ) 
    	{
    		$client = apply_filters( 'set_theme_client', $client );
    		wp_enqueue_style( $client.'-css' );
    	}
    	add_action( 'wp_head', 'print_device_styles', 11 );
    
    /**
     * TEMPLATE PARTS
     * The functionallows 3 subfolders for template parts that sit in a theme root folder named _devices_.
     */
    	function get_device_template_part( $args = array( 'file' => NULL, 'suffix' => 'default', 'client' => 'desktop', 'media' => 'screen' ) 
    	{
    		if ( ! $args['file'] )
    			wp_die( sprintf( __('You have to specify a file name if you want to load a template part with the %1$s function.', 'textdomain', '<pre>get_device_template_part()</pre>' );
    
    		$template_path = trailingslashit( STYLESHEETPATH.'/devices/templates-'.$args['client'] );
    		$ui_path = trailingslashit( STYLESHEETPATH.'/ui/css-'.$args['client'] );
    		$ui_suffix = '.css'; // could be switched between '.dev.css' & '.css'
    
    		// add styles & template directory
    		// NOTE: You have to define the following two functions on your own.
    		// Just get some device detection class and add them.
    		if ( is_condition_mobile() ) 
    		{
    			$args['client'] = 'mobile';
    			$args['screen'] = 'handheld';
    		}
    		elseif ( is_condition_tablet() )
    		{
    			$args['client'] = 'tablet';
    			$args['screen'] = 'handheld';
    		}
    
    		// register styles
    		// Example: wp_register_style( 'mobile-css', /theme_root/ui/css-mobile/mobile.css, false 'handheld' );
    		wp_register_style( $args['client'].'-css', $ui_path.$args['client'].$ui_suffix, false, $args['screen'] );
    
    		add_filter( 'set_theme_client', function('set_theme_client') { return $args['client'];} );
    
		// REQUIRE file
		// {$template}-{$suffix}.php
    		if ( file_exists( $template_path.$args['file'].'-'.$args['suffix'].'.php' ) )
    		{
    			require( $template_path.$args['file'].'-'.$args['suffix'].'php' );
    		}
		// {$template}.php
    		elseif ( file_exists( $template_path.$args['file'].'.php' ) )
    		{
    			require( $template_path.$args['file'].'.php' );
    		}
		// {$template}-default.php
    		elseif ( file_exists( $template_path.$args['file'].'-default.php' ) )
    		{
    			require( $template_path.$args['file'].'-default.php' );
    		}
    	}
    
    // CALL THEM in a template file
    // This will require a file named {$template}-{$suffix}.php from your devices folder
    // based on your conditional functions that detect your devices
    // If not found, it will search for a file named {$template}.php
    // and if it wasn't found it will search for a file named {$template}-default.php
    	get_device_template_part( array( 'file' => 'nav', 'suffix' => 'main' ) );
?>