class Database {
    public $isConn;
    protected $datab;

    // Connect zur DB
    public function __construct($username = "root_portal", $password = "Mxt59l$4", $host = "localhost", $dbname = "db12354864"){
        $this->isConn = TRUE;
        try{
            $this->datab = new PDO("mysql:host={$host};dbname={$dbname};charset=utf8", $username, $password);

            $this->datab->setAttribute(PDO::ATRR_ERRMODE, PDO::ERRMODE_EXCEPTION);
            $this->datab->setAttribute(PDO::ATRR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);

        }catch(PDOException $e){
            throw new Exception($e->getMessage());

        }
    }
    // Verbindung beenden
    public function Disconnect(){
        $this->datab = NULL;
        $this->isConn = FALSE;
    }
    // Hole eine Spalte
    public function getRow($query, $params = array()){
        try {
            $stmt = $this->datab->prepare($query);
            $stmt->execute($params);
            return $stmt->fetch();
        }catch (PDOException $e){
            throw new Exception($e->getMessage());
        }
    }
}

test php
<?php

require_once 'module/mysqli.php';

$db = new Database();

$getRow = $db->getRow("SELECT * FROM user WHERE id = ?", $params = array(1));
var_dump($getRow);

?>