获取自定义帖子类型的归档类别ID

Question

I'm trying to get the ID of the category on a category archive page of a custom post type. So far, I'm using the code below, but it doesn't seem to be working. This code is in my taxonomy-{taxonomy}.php file.

$cat_name = single_cat_title('', false);
$cat_id = get_cat_ID($cat_name);

// $cat_name = 'Category Name', which works fine but,
// $cat_id = 0, which is obviously not the id of the category

Do I need to do something special for retrieving the ID of a category of a custom post type?

As a side note, I need this, so I can pass the ID into the get_categories() function

$args = array(
    'child_of' => $cat_id,
    'taxonomy' => 'taxonomy'
);

$categories = get_categories($args);

Answer 1

There are several ways to get the category id

$category = get_category( get_query_var( 'cat' ) );
$cat_id = $category->cat_ID;

OR

$category = get_the_category(); 
$cat_id = $category[0]->cat_ID; // or foreach through

OR

if(is_category()) { $cat_ID = get_query_var('cat'); }

OR just

var_dump($wp_query->get_queried_object())

will give the current object for the template like for query on a category archive this is the category object

OR even none of these worked then here is the custom query

global $wpdb;
$category=$wpdb->get_results("SELECT * FROM `wp_terms` WHERE `name` ='$cat_name'");
$category[0]->term_id;

Answer 2

wp_get_ post _categories can only get POST categories not a custom post's categories, try this instead:

$category = get_the_terms( $post->ID, 'custom-taxonomy-here' ); //////find custom taxonomy category name
foreach ( $category as $cat){
echo $cat->name;
}

http://wordpress.org/support/topic/wp_get_post_categories-equivalent-for-custom-taxonomies