buddypress-activity-post-with-wp-user-frontend

function wpuf_bp_add_user_activity($activity_content) {
    global $bp;
    $user_id = get_current_user_id();
    $from_user_link = bp_core_get_userlink($user_id);
    $activity_action = sprintf(__('%s posted an update', 'buddypress'), $from_user_link);
    $primary_link = bp_core_get_userlink($user_id, false, true);
    $activity_id = bp_activity_add(array(
        'user_id' => $user_id,
        'action' => $activity_action,
        'content' => $activity_content,
        'primary_link' => $primary_link,
        'component' => $bp->activity->id,
        'type' => 'activity_update'
    ));
    return $activity_id;
}

function wpuf_bp_add_group_activity($group_id, $content) {
    $user_id = get_current_user_id();
    $activity_id = groups_post_update(array(
        'user_id' => $user_id,
        'group_id' => $group_id,
        'content' => $content
    ));
    return $activity_id;
}

function wpufe_add_bp_activities($post_id) {
    if (isset($_POST['bp_activity'])) {
        $content = trim($_POST['bp_activity']);
        if (!strlen($content)) {
            return;
        }
        $group_id = 1;
        wpuf_bp_add_user_activity($content);
        wpuf_bp_add_group_activity($group_id, $content);
    }
}
add_action('wpuf_add_post_after_insert', 'wpufe_add_bp_activities');