BuddyPress - Exclude Posts From The Activity Stream by Category

filter_activity_stream_by_category.php

<?php
// Exclude posts from the activity stream by category
function filter_activity_stream_by_category($where_conditions, $select_sql, $from_sql, $join_sql, $where_sql) {
    // Get the term ID for the parent category 'your-category-slug'
    $parent_category_id = get_cat_ID('your-category-slug'); // Change 'your-category-slug' to the slug of the category you would like to exclude and all it's subcategories 
    
    // Get all child category IDs of 'category-slug'
    $child_categories = get_term_children($parent_category_id, 'category');
    $child_categories_ids = array_map('intval', $child_categories); // Ensure they are integers
    
    // Include the parent category ID if also required to be excluded
    $child_categories_ids[] = $parent_category_id;
    // Convert category IDs to a comma-separated string
    $categories_string = implode(',', $child_categories_ids);
    // Get posts IDs in these categories
    $query_args = array(
        'posts_per_page' => -1,
        'category_in' => $child_categories_ids, // Use category_in to include children
        'fields' => 'ids'
    );
    $posts_in_categories = get_posts($query_args);
    // Convert IDs to string format for SQL query
    if (!empty($posts_in_categories)) {
        $ids_to_exclude = implode(',', $posts_in_categories);
        $where_conditions['exclude_posts'] = "a.secondary_item_id NOT IN ($ids_to_exclude)";
    }
    return $where_conditions;
}
add_filter('bp_activity_get_where_conditions', 'filter_activity_stream_by_category', 10, 5);