Demonsrtation of OOP in a WordPress Custom Post Type Plugin

oop-plugin-full.php

<?php

/*
* Plugin Name: OOP Custom Post Type Plugin
* Plugin URI: https://gist.github.com/johnregan3/434a511bbab95fdd33e1
* Description: Simple demonstration of OOP in a plugin
* Author: johnregan3
* Author URI: http://johnregan3.wordpress.com
* Version: 0.1
* Text Domain: jr3-oop-plugin
* License: GNU General Public License v2 or later
* License URI: http://www.gnu.org/licenses/gpl-2.0.html
* 
* @package WordPress
* @subpackage JR3 OOP Plugin
*/


/**
 * Contents of OOP CPT Plugin
 *
 * @since  0.1.0
 * @access public
 */
class JR3_Books {


	/**
	 * Fires all hooks for this plugin
	 *
	 * @static
	 * @action  init
	 * @action  manage_pages_custom_column
	 * @action  restrict_manage_posts
	 * @filter  manage_edit-jr3_Docs_columns
	 * @filter  parse_query
	 * @return  void
	 */
	static function setup() {
		add_action( 'init', array( __CLASS__, 'register_books_cpt' ) );
		add_action( 'init', array( __CLASS__, 'register_genres_taxonomy' ) );

		/*
		 * Extras 
		 *
		 * Just some fun stuff to do with the Post List.
		 * Adding/populating a custom "Genre" column, as well as a filter to sort by Genre.
		 */
		add_filter( 'manage_edit-jr3_books_columns', array( __CLASS__, 'register_columns' ) );
		add_action( 'manage_pages_custom_column', array( __CLASS__, 'populate_column' ), 10, 2 );
		add_action( 'restrict_manage_posts', array( __CLASS__, 'render_genres_filter' ) );
		add_filter( 'parse_query', array( __CLASS__, 'filter_genres' ) );
	}


	/**
	 * Basic setup of a Custom Post Type
	 *
	 * @static
	 * @uses    regsiter_post_type()
	 * @return  void
	 */
	static function register_books_cpt() {

		$labels = array(
			'name'               => __( 'Books', 'jr3-oop-plugin' ),
			'singular_name'      => __( 'Book', 'jr3-oop-plugin' ),
			'all_items'          => __( 'All Books', 'jr3-oop-plugin' ),
			'add_new_item'       => __( 'Add New Book', 'jr3-oop-plugin' ),
			'edit_item'          => __( 'Edit Book', 'jr3-oop-plugin' ),
			'new_item'           => __( 'New Book', 'jr3-oop-plugin' ),
			'view_item'          => __( 'View Book', 'jr3-oop-plugin' ),
			'search_items'       => __( 'Search Books', 'jr3-oop-plugin' ),
			'parent_item_colon'  => __( 'Parent Book', 'jr3-oop-plugin' ),
		);

		register_post_type( 'jr3_books',
			array(
				'labels'        => $labels,
				'public'        => true,
				'has_archive'   => true,
				'menu_position' => 21,
				'hierarchical'  => true,
				'taxonomies'    => array(
					'jr3_genres',
				),
				'supports'      => array(
					'title',
					'editor',
					'revisions',
					'page-attributes',
				),
			)
		);
	}


	/**
	 * Register Custom Taxonomy for this Custom Post Type
	 *
	 * @static
	 * @return  void
	 */
	static function register_genres_taxonomy() {

		$labels = array(
			'name'               => __( 'Genres', 'jr3-oop-plugin' ),
			'singular_name'      => __( 'Genre', 'jr3-oop-plugin' ),
			'all_items'          => __( 'All Genres', 'jr3-oop-plugin' ),
			'add_new_item'       => __( 'Add New Genre', 'jr3-oop-plugin' ),
			'edit_item'          => __( 'Edit Genre', 'jr3-oop-plugin' ),
			'new_item'           => __( 'New Genre', 'jr3-oop-plugin' ),
			'view_item'          => __( 'View Genre', 'jr3-oop-plugin' ),
			'search_items'       => __( 'Search Genres', 'jr3-oop-plugin' ),
			'parent_item_colon'  => __( 'Parent Genre', 'jr3-oop-plugin' ),
		);

		register_taxonomy(
			'jr3_genres',
			'jr3_books',
			array(
				'labels' => $labels,
				'show_ui' => true,
				'hierarchical' => true,
			)
		);
	}


	/**
	 * Insert new column into Post list
	 *
	 * @static
	 * @param   array  $columns  Post List columns
	 * @return  array  Updated Post List Columns
	 */
	static function register_columns( $columns ) {
		$columns['jr3_genres'] = 'Genre';
		return $columns;
	}


	/**
	 * Fill our Genres column with this post's Genre
	 *
	 * @static
	 * @uses   get_the_term_list()
	 * @param  array $column   Post List column
	 * @param  int   $post_id  Post ID
	 * @return void
	 */
	static function populate_column( $column, $post_id ) {
		if ( 'jr3_genres' == $column ) {
			$terms = get_the_term_list( $post_id , 'jr3_genres' , '' , ',' , '' );
            if ( is_string( $terms ) ) {
				echo $terms;
			}
		}
	}


	/**
	 * Creates a "Genres" (Taxonomy) dropdown above the Post list
	 *
	 * @static
	 * @uses    get_current_screen()
	 * @uses    wp_dropdown_categories()
	 * @global  $wp_query
	 * @return  void
	 */
	static function render_genres_filter() {

		$screen = get_current_screen();

		if ( $screen->post_type == 'jr3_books' ) {
			global $wp_query;

			$selected = ( isset( $wp_query->query['jr3_genres'] ) ? $wp_query->query['jr3_genres'] : '' );

			$args = array(
				'show_option_all' => 'All Genres',
				'taxonomy'        => 'jr3_genres',
				'name'            => 'jr3_genres',
				'orderby'         => 'name',
				'selected'        => $selected,
				'hierarchical'    => false,
				'depth'           => 3,
				'show_count'      => false,
				'hide_empty'      => true,
			);

			wp_dropdown_categories( $args );
		}
	}


	/**
	 * Performs the project taxonomy filtering
	 *
	 * @static
	 * @param   obj  $query  WP_Query object
	 * @return  void
	 */
	static function filter_genres( $query ) {
		$query_vars = &$query->query_vars;
		if ( isset( $query_vars['jr3_genres'] ) && is_numeric( $query_vars['jr3_genres'] ) ) {
			$term = get_term_by( 'id', $query_vars['jr3_genres'], 'jr3_genres' );
			if ( $term ) {
				$query_vars['jr3_genres'] = $term->slug;
			}
		}
	}

}

//This loads the plugin by firing the setup() method (or "function").
add_action( 'plugins_loaded', array( 'JR3_Books', 'setup' ) );