Custom post type archive page not showing on archive-posttype.php

Question

I am trying to create archives page for my custom post types but it is going to a default archive page not the archive page which i have created for archives

Here is my code for custom post type

    // Register Custom Post Type
function gallery_post_type() {

    $labels = array(
        'name' => _x('Gallery images', 'Post Type General Name', 'horst'),
        'singular_name' => _x('Gallery image', 'Post Type Singular Name', 'horst'),
        'menu_name' => __('Photo Gallery', 'horst'),
        'name_admin_bar' => __('Photo Gallery', 'horst'),
        'archives' => __('Item Archives', 'horst'),
        'parent_item_colon' => __('Parent Photo:', 'horst'),
        'all_items' => __('All Photos', 'horst'),
        'add_new_item' => __('Add New Photo', 'horst'),
        'add_new' => __('Add New Gallery image', 'horst'),
        'new_item' => __('New Photo', 'horst'),
        'edit_item' => __('Edit Photo', 'horst'),
        'update_item' => __('Update Photo', 'horst'),
        'view_item' => __('View Photo', 'horst'),
        'search_items' => __('Search Photos', 'horst'),
        'not_found' => __('Not found', 'horst'),
        'not_found_in_trash' => __('Not found in Trash', 'horst'),
        'featured_image' => __('Gallery Image', 'horst'),
        'set_featured_image' => __('Set Gallery image', 'horst'),
        'remove_featured_image' => __('Remove Gallery image', 'horst'),
        'use_featured_image' => __('Use as Gallery image', 'horst'),
        'insert_into_item' => __('Insert into item', 'horst'),
        'uploaded_to_this_item' => __('Uploaded to this Photo', 'horst'),
        'items_list' => __('Photos list', 'horst'),
        'items_list_navigation' => __('Photo list navigation', 'horst'),
        'filter_items_list' => __('Filter Photo list', 'horst'),
    );
    $args = array(
        'label' => __('Gallery image', 'horst'),
        'description' => __('gallery imges for gallery page', 'horst'),
        'labels' => $labels,
        'supports' => array('title', 'thumbnail',),
        'hierarchical' => true,
        'taxonomies' => array(
            'gallery_categories',
        ),
        'rewrite' => array(
            'slug' => 'gallery',
        ),
        'public' => true,
        'show_ui' => true,
        'show_in_menu' => true,
        'menu_position' => 5,
        'menu_icon' => 'dashicons-format-gallery',
        'show_in_admin_bar' => true,
        'show_in_nav_menus' => true,
        'can_export' => true,
        'has_archive' => true,
    );
    register_post_type('gallery', $args);
}

add_action('init', 'gallery_post_type');

and this is my custom taxonomy

// Register Custom Taxonomy
function custom_taxonomy() {

    $labels = array(
        'name'                       => _x( 'Gallery Maps', 'Taxonomy General Name', 'text_domain' ),
        'singular_name'              => _x( 'Gallery Map', 'Taxonomy Singular Name', 'text_domain' ),
        'menu_name'                  => __( 'Gallery Maps', 'text_domain' ),
        'all_items'                  => __( 'All Items', 'text_domain' ),
        'parent_item'                => __( 'Parent Item', 'text_domain' ),
        'parent_item_colon'          => __( 'Parent Item:', 'text_domain' ),
        'new_item_name'              => __( 'New Item Name', 'text_domain' ),
        'add_new_item'               => __( 'Add New Item', 'text_domain' ),
        'edit_item'                  => __( 'Edit Item', 'text_domain' ),
        'update_item'                => __( 'Update Item', 'text_domain' ),
        'view_item'                  => __( 'View Item', 'text_domain' ),
        'separate_items_with_commas' => __( 'Separate items with commas', 'text_domain' ),
        'add_or_remove_items'        => __( 'Add or remove items', 'text_domain' ),
        'choose_from_most_used'      => __( 'Choose from the most used', 'text_domain' ),
        'popular_items'              => __( 'Popular Items', 'text_domain' ),
        'search_items'               => __( 'Search Items', 'text_domain' ),
        'not_found'                  => __( 'Not Found', 'text_domain' ),
        'no_terms'                   => __( 'No items', 'text_domain' ),
        'items_list'                 => __( 'Items list', 'text_domain' ),
        'items_list_navigation'      => __( 'Items list navigation', 'text_domain' ),
    );
    $args = array(
        'labels'                     => $labels,
        'hierarchical'               => true,
        'public'                     => true,
        'show_ui'                    => true,
        'show_admin_column'          => true,
        'show_in_nav_menus'          => true,
        'show_tagcloud'              => true,
    );
    register_taxonomy( 'gallery_categories', array( 'gallery' ), $args );

}
add_action( 'init', 'custom_taxonomy');

I don't know where am i doing wrong?

Answer 1

Custom template should be archive-gallery.php instead of archive-posttype.php

It's archive-$posttype.php where $posttype is the custom post type slug.

WordPress first looks for archive-$posttype.php and if it's not available then chooses archive.php

Update

Same for the custom taxonomies also , the flow is:

taxonomy-$taxonomy-$term.php --> taxonomy-$taxonomy.php -->  taxonomy.php --> archive.php

So for gallery_categories custom taxonomy use taxonomy-gallery_categories.php