wp_list_categories + widget

Question

With the code below, I added a span tag + placed the category count inside the link.

add_filter('wp_list_categories', 'cat_count_span');    
function cat_count_span($links) {       
    $links = str_replace('</a> (', '<span>', $links);
    $links = str_replace(')', '</span></a>', $links);
    return $links;    
}

The problem I'm having... this modification will apply on all pages or widgets that uses wp_list_categories. And I'd like to have the opposite effect. The code should only apply inside my custom made category widget.

What do I need to change so it will work the way I'd like it to work?

Answer 1

Your widget must have a method that looks something like this:

public function widget( $args, $instance ) {
    echo $args['before_widget'];
    if ( ! empty( $instance['title'] ) ) {
        echo $args['before_title'] . apply_filters( 'widget_title', $instance['title'] ). $args['after_title'];
    }
    wp_list_categories();
    echo $args['after_widget'];
}

Apply your filter inside that method, then remove it:

public function widget( $args, $instance ) {
    echo $args['before_widget'];
    if ( ! empty( $instance['title'] ) ) {
        echo $args['before_title'] . apply_filters( 'widget_title', $instance['title'] ). $args['after_title'];
    }
    add_filter('wp_list_categories', 'cat_count_span'); 
    wp_list_categories();
    remove_filter('wp_list_categories', 'cat_count_span'); 
    echo $args['after_widget'];
}

The same thing works with the backend form method.

Reference:
https://codex.wordpress.org/Widgets_API#Example