class KnopHandler implements ActionListener{
        private Rekenmachine rekenmachine;
            public void actionPerformed(ActionEvent e){
                Rekenmachine r = new Rekenmachine();
                if(e.getSource() == buttons[1]){
                    r.setTextVak();
                }
                if(e.getSource() == buttons[2]){
                    System.out.println("bla");
                }
            }
    }