Here is the solution that we discussed on
http://buddypress.org/support/topic/filter-members-list-based-on-profile-field/
It is based on http://codex.buddypress.org/developer/bp_user_query/#code-examples
class BP_Custom_User_Ids {
private $custom_ids = array();
public function __construct() {
$this->custom_ids = $this->get_custom_ids();
add_action( 'bp_pre_user_query_construct', array( $this, 'custom_members_query' ), 1, 1 );
add_filter( 'bp_get_total_member_count', array( $this, 'custom_members_count' ), 1, 1 );
}
private function get_custom_ids() {
global $wpdb;
//figure out if the logged-in user is male or female
$sex = xprofile_get_field_data( 5, bp_loggedin_user_id() );
if ( $sex == 'Male' )
$query = "SELECT user_id FROM {$wpdb->prefix}bp_xprofile_data WHERE field_id = 5 AND value="Female"";
else
$query = "SELECT user_id FROM {$wpdb->prefix}bp_xprofile_data WHERE field_id = 5 AND value="Male"";
$custom_ids = $wpdb->get_col( $query );
return $custom_ids;
}
function custom_members_query( $query_array ) {
$query_array->query_vars['include'] = $this->custom_ids;
}
function custom_members_count ( $count ) {
$new_count = count( $this->custom_ids );
return $new_count;
}
}
function custom_user_ids( ) {
new BP_Custom_User_Ids ();
}
add_action( 'bp_before_directory_members', 'custom_user_ids' );