Using categories with pages

Question

I am attempting to use categories for pages (not posts) as a way of filtering child pages.

I am working towards having a 'Work' page that lists all its children, and each of these children will also have categories applied to them. Another sub menu will allow you to choose a category and only those child pages will be listed.

So far:

functions.php - Show categories meta box for pages

function myplugin_settings() {  
    register_taxonomy_for_object_type('category', 'page');  
}
add_action( 'init', 'myplugin_settings' );

Set up a category menu, which is rendered on my 'work' page

<?php wp_nav_menu(array('theme_location' => 'category-menu')); ?>

category.php - Get the ID of the category we're looking at

<?php get_header(); ?>

<?php $cat_id = get_cat_id( single_cat_title("",false) ); ?>

<p>
<?php echo $cat_id; ?>
</p>

<?php get_footer(); ?>

This is where I am stuck: How can I loop though my work child pages that have the category ID that I am getting in my category.php template?

I understand that categories aren't really designed for pages so I am open to suggestions as to how to set and filter my pages by some kind of category.

I am already using Advanced Custom Fields so there is scope to use that; I would rather not use any other plugins.

Answer 1

As you have stated, pages aren't meant to have categories. I would rather look into custom post types and taxonomies, but the implementation is still up to you as I don't know your structures

I have never tried this before, neither do I know if this will actually work, but you can try the pre_get_posts action to amend the main query to display pages on your category.php template

add_action( 'pre_get_posts', function ( $query ) {
    if ( !is_admin() && $query->is_category() && $query->is_main_query() ) {
        $query->set( 'post_type', array( 'post', 'page' ) );
    }
});