/* parte 1 */
        public function OpenConnection(){

            $connection = mysqli_connect(Database::_HOST, Database::_DB_USER, Database::_DB_PASSWORD, Database::_DB);

            mysqli_set_charset($connection,"utf8");

            if(!$connection){
                echo "<p font color=\"red\">Erro: Não foi possível conectar com o banco de dados." . PHP_EOL . "</p>";
                echo "<p font color=\"red\">Erro: " . mysqli_connect_errno() . PHP_EOL . "</p>";
                echo "<p font color=\"red\">Erro: " . mysqli_connect_error() . PHP_EOL . "</p>";
            }
            return $connection;
        }//DBOpenConnection's end

/* parte 2 */

        $connection = Database::getInstance()->OpenConnection();
            $sql = "select * from user where user_name = ? and password = ?;";
            $statement = $connection->prepare($sql);

            //if any error happen in connection
            if (!$statement) {
                echo 'erro na consulta: '. $connection->errno .' - '. $connection->error;
            }

            //associate the user name and password with sql parameters,
            //execute the query and store the result
            $statement->bind_param('ss', $userName,$password);
            $statement->execute();
            $result = $statement->get_result();

            $user;

            //create and set the user variable
            while($row = mysqli_fetch_array($result)){

                $user = new User($row["idUser"], $row["name"], $row["email"], $row["user_name"], $row["password"], $row["type"], $row["active"], $row["idAdministrator"]);
            }

            echo "teste: ".$user->name;

            //close statement and connection
            $statement->close();
            Database::getInstance()->CloseConnection($connection);

            return $user; //aqui ta retornando nulo...