Change the behaviour of archive cpt category and single cpt by plugin, not by theme

Question

I need to know: I have wrote at 60% one plugin, it works well in backend (some settings, some cpt, some custom fields... nothing special). It uses custom post type with custom fields.

For now I need to change default archive category behaviour as well as change behaviour of single posts of this CPT _doesn't_touching_ templates (because this plugin will be used not only in the 1 site and there will be many templates).

Just programmatically, by filters/actions - change it as I like.. for example, I will need to show up this custom fields in this single custom post type.

Does somebody knows about how to do it by plugin?

Answer 1

You can use templates located within your plugin instead of theme files, like so:

add_filter('archive_template', 'redirect_to_plugin_archive_template');
function redirect_to_plugin_archive_template($template) {

    if(is_post_type_archive('my_cpt')) {
        return dirname(__FILE__) . '/templates/my_archive_template.php';
    }
}

add_filter('single_template', 'redirect_to_plugin_single_template');
function redirect_to_plugin_single_template($template) {

    if(is_singular('my_cpt')) {
        return dirname(__FILE__) . '/templates/my_single_template.php';
    }
}

Obviously you need to change the custom post type slug and the template paths, but that's the general idea.