WordPress costom post type with it's own taxonomy. Also adds an archive option to show the posts ordered by taxonomy name

rrwd_custom_post_type_with_taxonomy.php

<?php
/**
* This code adds a costom post type with it's own taxonomy to WordPress
* And adds an archive option to show the posts ordered by taxonomy name
* Rian Rietveld - rrwd.nl
* November 22, 2012
* Add this to the functions.php in your WordPress child theme
* Here, as an example, the custom post type is book and the taxonony is genre
*/


// define and register the custom post type
function register_prefix_name_cpt() {

$labels = array(
    'name' => _x('Books', 'post type general name', 'your_text_domain'),
    'singular_name' => _x('Book', 'post type singular name', 'your_text_domain'),
    'add_new' => _x('Add New', 'book', 'your_text_domain'),
    'add_new_item' => __('Add New Book', 'your_text_domain'),
    'edit_item' => __('Edit Book', 'your_text_domain'),
    'new_item' => __('New Book', 'your_text_domain'),
    'all_items' => __('All Books', 'your_text_domain'),
    'view_item' => __('View Book', 'your_text_domain'),
    'search_items' => __('Search Books', 'your_text_domain'),
    'not_found' =>  __('No books found', 'your_text_domain'),
    'not_found_in_trash' => __('No books found in Trash', 'your_text_domain'), 
    'parent_item_colon' => __('Parent item: ', 'your_text_domain'), 
    'menu_name' => __('Books', 'your_text_domain')

  );
  $args = array(
  'labels' => $labels,
        'hierarchical' => true,
        'description' => __( 'Description here','your_text_domain'),
        'supports' => array( 'title', 'editor', 'excerpt', 'thumbnail' ),
        'taxonomies' => array( 'prefix_name_taxonomy' ),
        'public' => true,
        'show_ui' => true,
        'show_in_menu' => true,
        'menu_position' => 21,
        'show_in_nav_menus' => true,
        'publicly_queryable' => true,
        'exclude_from_search' => false,
        'has_archive' => true,
        'query_var' => true,
        'can_export' => true,
    	'rewrite' => array( 'slug' => __( 'book', 'URL slug', 'your_text_domain' ) ),
        'capability_type' => 'page'
  ); 

    register_post_type( 'prefix_name_cpt', $args );
}
add_action( 'init', 'register_prefix_name_cpt' );


// add the custom post type to the query results
function prefix_get_posts( $query ) {
    
	if ( is_category() || is_tag() && empty( $query->query_vars['suppress_filters'] ) && !is_admin()  )
		$query->set( 'post_type', array( 'post', 'page', 'prefix_name_cpt', 'nav_menu_item','prefix_name_taxonomy' ) );

	return $query;
}
add_action( 'pre_get_posts', 'prefix_get_posts' );


// define and register the  taxonony
function prefix_create_prefix_name_taxonomy()  {

	$labels = array(
    	'name' => _x( 'Genres', 'taxonomy general name' ),
    	'singular_name' => _x( 'Genre', 'taxonomy singular name' ),
    	'search_items' =>  __( 'Search Genres' ),
    	'all_items' => __( 'All Genres' ),
    	'parent_item' => __( 'Parent Genre' ),
    	'parent_item_colon' => __( 'Parent Genre:' ),
    	'edit_item' => __( 'Edit Genre' ), 
    	'update_item' => __( 'Update Genre' ),
    	'add_new_item' => __( 'Add New Genre' ),
    	'new_item_name' => __( 'New Genre Name' ),
    	'menu_name' => __( 'Genre' ),
  	); 	

  	register_taxonomy( 'prefix_name_taxonomy', array( 'prefix_name_cpt' ), array(
    	'hierarchical' => true,
    	'labels' => $labels,
    	'show_ui' => true,
    	'query_var' => true,
    	'rewrite' => array( 'slug' => 'name_taxonomy' ),
  	) );
  
}  
add_action( 'init', 'prefix_create_prefix_name_taxonomy', 0 );


/**
* Get the custom post type, ordered alphabetically by taxonomy name
* The posts are ordered by date
* The taxonomies are placed inside a div, with an H2 as heading
* This function can (for example) be added in a template file archive-prefix_name_cpt.php of your child theme
* 
*/

function prefix_show_ctp_by_taxonomy() {
	// thanks to nickam at http://wordpress.org/support/topic/list-posts-by-taxonomy-tag
	
	$post_type = 'prefix_name_cpt';
	$tax = 'prefix_name_taxonomy';
	$tax_terms = get_terms( $tax, 'hide_empty=0' );

	$nr_div = 1; // counter for the displayed div's, to add extra style at the third block
	
	// list for each taxonomy, list the posts
	if ( $tax_terms ) {
		
  		foreach ( $tax_terms  as $tax_term ) {
			
    		$args = array(
     	 		'post_type' => $post_type,
    	  		"$tax" => $tax_term->slug,
     	 		'post_status' => 'publish',
      			'posts_per_page' => -1,
				'ordery' => 'date'
    		);
	
   		 	$my_query = null;
   			$my_query = new WP_Query ($args );
			
   			if( $my_query->have_posts() ) {

				if ( fmod($nr_div, 3) == 0 ) { // add an extra style class to the third div for changing margins for example
					echo '<div class="prefix-cpt-tax-div last">'."\n";
				} else {
					echo '<div class="prefix-cpt-tax-div">'."\n";					
				}
	      		echo '	<h2>' .  $tax_term->name . "</h2>\n";
				
				echo "	<ul>\n";
				
	      		while ( $my_query->have_posts() ) : $my_query->the_post(); 
        			?>		<li><a href="<?php the_permalink() ?>"><?php the_title(); ?></a></li><?php
     			endwhile;
				
				echo "	</ul> \n";
				
				echo "</div><!-- end .prefix-cpt-tax-div --> \n";
				
				$nr_div++;
				
    		}
			
    		wp_reset_query();
			
  		}	
	}	
	
}
?>