import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import java.awt.GridLayout;

public class GridEksempel {
    public static void main(String[] args) {
        /* Setter opp vinduet */
        try {
            UIManager.setLookAndFeel(
                UIManager.getCrossPlatformLookAndFeelClassName());
        } catch (Exception e) {
            System.exit(1);
        }

        JFrame vindu = new JFrame("Mitt Program");
        vindu.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();
        vindu.add(panel);

        /* Lager ActionListener til knappene, slik at de skriver ut nr naar man trykker */
        // (Trenger ikke aa gjoere dette, kan ogsaa ha knapper som ikke gjoer noe)
        class KnappListener implements ActionListener {
            int nr;
            public KnappListener(int nr) {
                this.nr = nr;
            }

            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println(nr);
            }
        }

        /* Lager rutenettet */
        int rader = 3;
        int kol = 4;
        panel.setLayout(new GridLayout(rader, kol));

        int teller = 1;

        // For hver kolonne i hver rad, sett en knapp der
        for (int r = 0; r < rader; r++ ) {
            for (int k = 0; k < kol; k++) {
                JButton nrKnapp = new JButton("" + teller);
                nrKnapp.addActionListener(new KnappListener(teller));
                teller++;
                panel.add(nrKnapp);
            }
        }

        /* Pakker sammen og viser GUI-vinduet */
        vindu.pack();
        vindu.setVisible(true);
    }
}