有没有办法在帖子类型中获取所有已注册的元字段？

Question

I'm creating a dynamic form that user can select a post type and show all meta fields registered on that selected post type, is there a way to get all meta fields in a post types?

Answer 1

You'll use custom sql query to get these meta keys/fields.

With this function you'll be able to exclude/include the empty meta_keys and the hidden ones.

function get_all_meta_keys($post_type = 'post', $exclude_empty = false, 
    $exclude_hidden = false){
    global $wpdb;
    $query = "
        SELECT DISTINCT($wpdb->postmeta.meta_key) 
        FROM $wpdb->posts 
        LEFT JOIN $wpdb->postmeta 
        ON $wpdb->posts.ID = $wpdb->postmeta.post_id 
        WHERE $wpdb->posts.post_type = '%s'
    ";
    if($exclude_empty) 
        $query .= " AND $wpdb->postmeta.meta_key != ''";
    if($exclude_hidden) 
        $query .= " AND $wpdb->postmeta.meta_key NOT RegExp '(^[_0-9].+$)' ";

    $meta_keys = $wpdb->get_col($wpdb->prepare($query, $post_type));

    return $meta_keys;
}