import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.util.Random;
import java.util.Scanner;

class EndreFarge {
    public static void main (String[] arg) {
        JFrame vindu = new JFrame("Endre farge p? en knapp");
        vindu.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(5,5));
        
        vindu.add(panel);

        // Lager sjakkmoenster. Anenhver er hvit og svart
        for (int i = 0; i < 25; i++) {
            if (i % 2 == 0)
                panel.add(new MinKnapp(Color.WHITE));
            else
                panel.add(new MinKnapp(Color.BLACK));
        }

        vindu.pack();
        vindu.setVisible(true);
    }
}

class MinKnapp extends JButton{

    boolean farget = false;
    Color start;
    Random r = new Random();

    public MinKnapp(Color start){
        this.start = start;
        initGUI();
    }

    class EndreKnappTekst implements ActionListener{
    
        @Override
        public void actionPerformed(ActionEvent e){
            farget = !farget;
            if(farget){
                // Setter fargen til aa vaere en tilfeldig farge
                Color c = new Color(r.nextInt(256),r.nextInt(256),r.nextInt(256),r.nextInt(256));
                setBackground(c);
            } 
            else{
                setBackground(start);
            } 
        }
    }

    public void initGUI(){
        setBackground(start);
        // For aa faa farge paa mac:
        setOpaque(true);            // Gjoer knappen gjennomsiktig
        setBorderPainted(false);    // Fjerner kantene slik at knappen er usynlig
        addActionListener(new EndreKnappTekst());
    }
}