import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JRadioButton;

public class testje3 extends JFrame {

    public class GooiHandler implements ActionListener {
        @Override
        public void actionPerformed(ActionEvent e) {
            int will = 1 + (int) (Math.random() * 6);
            if (radBlauw.isSelected() == true) {
                for (int i = 0; i < will; i++) {
                    btn[i].setBackground(Color.BLUE);
                }
                for (int i = 0; i < btn.length; i++) {
                    btn[i].setBackground(Color.LIGHT_GRAY);
                }
            } else {
                for (int i = 0; i < will; i++) {
                    btn[i].setBackground(Color.RED);
                }
                for (int i = 0; i < btn.length; i++) {
                    btn[i].setBackground(Color.LIGHT_GRAY);
                }
            }
        }
    }

    JRadioButton radBlauw = new JRadioButton("Blauw");
    JRadioButton radRood = new JRadioButton("Rood");
    JButton btn[] = new JButton[6];
    JButton btnGooi = new JButton("Gooi");

    public testje3() {
        super("Dobbelsteen");

        JPanel inhoudsPaneel = new JPanel(new BorderLayout());
        JPanel links = new JPanel(new GridLayout(1, 1));
        JPanel rechts = new JPanel(new GridLayout(3, 3));

        for (int i = 0; i < 6; i++) {
            btn[i] = new JButton();
            rechts.add(btn[i]);
        }
        inhoudsPaneel.setOpaque(true);

        links.add(btnGooi);
        rechts.add(radBlauw);
        rechts.add(radRood);

        inhoudsPaneel.add(links, BorderLayout.WEST);
        inhoudsPaneel.add(rechts, BorderLayout.EAST);

        btnGooi.addActionListener(new GooiHandler());

        add(inhoudsPaneel);

        setDefaultCloseOperation(DISPOSE_ON_CLOSE);
        setSize(400, 200);
        setLocation(500, 500);
        setVisible(true);

    }

    public static void main(String[] args) {
        new testje3();
    }
}