WordPress 技巧：后台文章列表添加自定义分类筛选

如果你的文章或者文章类型添加了自定义分类，下面的代码可以在 WordPress 后台文章列表添加自定义分类下拉筛选框，快速通过自定义分类筛选文章。

add_action('restrict_manage_posts', function($post_type){
	if($taxonomies	= get_object_taxonomies($post_type, 'objects')){
		foreach($taxonomies as $taxonomy) {

			if(empty($taxonomy->hierarchical) || empty($taxonomy->show_admin_column)){
				continue;
			}

			if($taxonomy->name == 'category'){
				$taxonomy_key	= 'cat';
			}else{
				$taxonomy_key	= $taxonomy->name.'_id';
			}

			$selected	= 0;
			if(!empty($_REQUEST[$taxonomy_key])){
				$selected	= $_REQUEST[$taxonomy_key];
			}elseif(!empty($_REQUEST['taxonomy']) && ($_REQUEST['taxonomy'] == $taxonomy->name) && !empty($_REQUEST['term'])){
				if($term		= get_term_by('slug', $_REQUEST['term'], $taxonomy->name)){
					$selected	= $term->term_id;
				}
			}elseif(!empty($taxonomy->query_var) && !empty($_REQUEST[$taxonomy->query_var])){
				if($term	= get_term_by('slug', $_REQUEST[$taxonomy->query_var], $taxonomy->name)){
					$selected	= $term->term_id;
				}
			}

			wp_dropdown_categories(array(
				'taxonomy'			=> $taxonomy->name,
				'show_option_all'	=> $taxonomy->labels->all_items,
				'show_option_none'	=> '没有设置',
				'hide_if_empty'		=> true,
				'hide_empty'		=> 0,
				'hierarchical'		=> 1,
				'show_count'		=> 0,
				'orderby'			=> 'name',
				'name'				=> $taxonomy_key,
				'selected'			=> $selected
			));
		}
	}
});