Ticket #21240: custom-taxonomy-columns.php

<?php
new CPT_Columns( 'Event', 'Evemts', 'dw-events' );

class CPT_Columns {

        private $single;
        private $plural;
        private $slug;
        private $taxonomies;
        static $instance;

        function __construct( $post_type, $plural = '', $slug = '' ) {

                self::$instance = $this;

                $this->single = $post_type;
                $this->plural = !empty( $plural ) ? $plural : $post_type .'s';
                $this->slug = !empty( $slug ) ? $slug : sanitize_title( $this->plural );

                add_filter( 'manage_edit-'. $this->slug .'_columns', array( &$this, 'columns' ) );
                add_action( 'manage_posts_custom_column', array( &$this, 'columns_display' ) );

        }

        public function columns( $columns ) {
                $taxonomies = get_object_taxonomies( $this->slug );

                if ( !empty( $taxonomies ) ){

                        foreach ( $taxonomies as $key => $tax ) {
                                if ( $tax == 'post_tag' || $tax == 'post_category' ) continue;

                                $object = get_taxonomy( $tax );
                                if ( !$object->hierarchical ) continue;

                                $this->taxonomies[] = $tax;


                                $columns[$tax.'_column'] = $object->label;
                        }
                }

                return $columns;
        }

        public function columns_display( $column ) {

                if ( !empty( $this->taxonomies ) ){

                        foreach ( $this->taxonomies as $tax ) {
                                if ( $column == $tax.'_column' ) {
                                        $this->taxonomy_column( $tax, ucfirst( str_replace( '-', ' ', $tax ) ) );
                                }
                        }
                }
        }

        public function taxonomy_column( $tax = '', $name = '' ) {
                global $post;
                $id = $post->ID;
                $categories = get_the_terms( $id, $tax );
                if ( !empty( $categories ) ) {
                        $out = array();
                        foreach ( $categories as $c ) {
                                $out[] = sprintf( '<a href="%s">%s</a>',
                                esc_url( add_query_arg( array( 'post_type' => $post->post_type, $tax => $c->slug ), 'edit.php' ) ),
                                esc_html( sanitize_term_field( 'name', $c->name, $c->term_id, 'category', 'display' ) )
                                );
                        }
                        echo join( ', ', $out );
                } else {
                        _e( 'No '. $name .' Specified' );
                }

        }
}