Using methods within Swing application

Question

I'm creating my first Swing application -> Tic Tac Toe. I've seen a lot of tutorials but I still can't understand three things:

The first is: How to create methods and use them in my code (e. g. isWinner method in my code below)? I added it to actionPerformed but it still won't do a thing. How should I call it to make it work real-time?

The second is: I'm not a fan of static methods. Shall I create an object of my class and then call methods?

The third is: Is my isWinner method ok? Or should I change the way I'm trying to check if the winner appears?

I saw a lot of content on the Internet and examples of creating games like that.

EDIT Changed the isWinner method. Now I call it from the actionPerformed method. Still does nothing...

package one.more.time;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

@SuppressWarnings("serial")
public class GameWindow extends JFrame implements ActionListener{

    String player = "X";
    JButton but[] = new JButton[9];
    JLabel status = new JLabel("Start!");


    public GameWindow() {
        setLayout(new BorderLayout());

        for (int i = 0; i < but.length; i++){
            but[i] = new JButton(Integer.toString(i+1));
            but[i].addActionListener(this);
        }

        JPanel gamePanel = new JPanel();
        gamePanel.setLayout(new GridLayout(3, 3));

        for (int i = 0; i < but.length; i++){
            gamePanel.add(but[i]);
        }

        add(gamePanel, BorderLayout.CENTER);
        add(status, BorderLayout.SOUTH);
        setSize(new Dimension(300, 300));
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        setVisible(true);
    }



    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new GameWindow();
            }
        });
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        JButton src = (JButton) e.getSource();
        src.setActionCommand("player");
        src.setText(player);
        src.setEnabled(false);
        if (isWinner(but, player)) {
            System.exit(0);
        };
    }

    boolean isWinner(JButton butt[], String player){
        JButton but[] = butt;
         for (int i = 0; i<3; i++){
         if (but[i].getActionCommand().equals(but[i+3].getActionCommand()) && 
                    but[i+3].getActionCommand().equals(but[i+6].getActionCommand()) &&
                    but[i].getActionCommand().equals(but[i+6].getActionCommand()) && 
                    but[i].getActionCommand().equals(player))
             {
                 return true;
             }
         }
         for (int i = 0; i<9; i+=3)
         if (but[i].getActionCommand().equals(but[i+1].getActionCommand()) && 
                     but[i+1].getActionCommand().equals(but[i+2].getActionCommand()) &&
                     but[i].getActionCommand().equals(but[i+2].getActionCommand()) &&
                    but[i].getActionCommand().equals(player))
            {
                return true;
            }

         if (but[0].getActionCommand().equals(but[4].getActionCommand()) && 
                 but[4].getActionCommand().equals(but[8].getActionCommand())&&
                 but[0].getActionCommand().equals(but[8].getActionCommand()) &&
                but[0].getActionCommand().equals(player))
        {
            return true;
        }
         if (but[2].getActionCommand().equals(but[4].getActionCommand()) && 
                 but[4].getActionCommand().equals(but[6].getActionCommand()) &&
                 but[2].getActionCommand().equals(but[6].getActionCommand()) &&
                but[2].getActionCommand().equals(player))
        {
            return true;
        }

         return false;
     }
}

Answer 1

1-2. Dont make isWinner static. That would allow you to call it from inside your class other non static methods: such as the actionPerformed method.

3. but [I]==but [I+3] - you just compare references of the different JButtons which would be false always. You need to compare the marked player behind them:

   but [I].getActionCommand ().equals ( but [I+3].getActionCommand ());

Edit: Inside the actionPerformed method don't write src.setActionCommand("player"); Replace it of course with the player's actual value: src.setActionCommand(player);

A slightly cleaner isWinner method:

boolean isWinner(JButton buttons[], String player)
{
    for (int i = 0; i < 3; i++)
    {
        if (buttons[i].getActionCommand().equals(player) &&
                buttons[i + 3].getActionCommand().equals(player) &&
                buttons[i + 6].getActionCommand().equals(player))
        {
            return true;
        }
    }

    for (int i = 0; i < 9; i += 3)
        if (buttons[i].getActionCommand().equals(player) &&
                buttons[i + 1].getActionCommand().equals(player) &&
                buttons[i + 2].getActionCommand().equals(player))
        {
            return true;
        }

    if (buttons[0].getActionCommand().equals(player) &&
            buttons[4].getActionCommand().equals(player) &&
            buttons[8].getActionCommand().equals(player))
    {
        return true;
    }

    return buttons[2].getActionCommand().equals(player) &&
            buttons[4].getActionCommand().equals(player) &&
            buttons[6].getActionCommand().equals(player);
}