A class to add a selectbox filter by custom field value in Custom Post Type listing page in admin

To add a select-box filter to any Post Type/Custom Post Type listing page, just create new object

new Admin_Custom_Field_Filter(array('CUSTOM-POST-TYPE' => array('CUSTOM-FIELD-1','CUSTOM-FIELD-2')));

in which, 'CUSTOM-POST-TYPE' is the name of the post type/custom post type you want to add 'CUSTOM-FIELD-1', 'CUSTOM-FIELD-2' are the names of the custom fields you want to filter by. Add many custom fields as you want, each item will add new select-box

By default, items in the select-box filter will have Text value the same with it's Value. To modify this value, use filter

add_filter('admin_custom_field_filter_value','custom_admin_custom_field_filter_value',10,3);

For examle

function custom_admin_custom_field_filter_value($value,$custom_post_type,$custom_field){ if($custom_post_type == 'custom-post-type' && $custom_field == 'custom-field'){ $post = get_post($value); if($post){ return $post->post_title; } } return $value; }