Lights out game using 2d arrays

Question

I'm trying to make a lights out game, I simplified it to only change one tile at a time but I'm still encountering one bug. I can click to change from yellow to black but I can't click and have the opposite happen. Here is the game if you are unfamiliar: http://www.logicgamesonline.com/lightsout/

My code:

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.net.*;

public class LightsOutPanel extends JPanel implements MouseListener {
    private boolean[][] lights;

    public static void main(String[] args) throws Exception {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setTitle("Lights Out!");
        frame.setResizable(false);
        frame.setVisible(true);

        LightsOutPanel panel = new LightsOutPanel();
        if (panel.lights == null) {
            System.out.println("You did not initialize your light array!" +
                               "It's still null...");
            System.exit(-1);
        }
        panel.addMouseListener(panel);
        panel.setPreferredSize(new Dimension(601, 501));
        panel.setMinimumSize(new Dimension(601, 501));

        Container c = frame.getContentPane();
        c.setLayout(new BorderLayout());
        c.add(panel, BorderLayout.CENTER);

        frame.pack();
    }

    public LightsOutPanel() {
        lights = new boolean[5][6];
        for (int i = 0; i < 5; i++) {
            for (int j = 0; j < 6; j++) {
                lights[i][j] = true;
            }
        }

    }

    // unused methods
    public void mouseClicked(MouseEvent e) {}

    public void mouseReleased(MouseEvent e) {}

    public void mouseEntered(MouseEvent e) {}

    public void mouseExited(MouseEvent e) {}

    public void paint(Graphics g) {
        int boxWidth = 600 / 6;
        int boxHeight = 500 / 5;

        int y = 0;
        for (int row = 0; row < 5; row++) {
            int x = 0;
            for (int col = 0; col < 6; col++) {
                if (lights[row][col]==true) {
                    g.setColor(Color.YELLOW);
                } else {
                    g.setColor(Color.BLACK);
                }
                g.fillRect(x, y, boxWidth, boxHeight);

                g.setColor(Color.BLUE);
                g.drawRect(x, y, boxWidth, boxHeight);
                x += boxWidth;
            }
            y += boxHeight;
        }
    }

    // called when the mouse is pressed - determines what row/column the user
    // has clicked
    public void mousePressed(MouseEvent e) {
        int mouseX = e.getX();
        int mouseY = e.getY();

        int panelWidth = getWidth();
        int panelHeight = getHeight();

        int boxWidth = panelWidth / lights[0].length;
        int boxHeight = panelHeight / lights.length;

        int col = mouseX / boxWidth;
        int row = mouseY / boxHeight;

        toggle(row, col);
        repaint();
    }

    // called to "toggle" the selected row and column, as well as the four
    // adjacent lights
    public void toggle(int row, int col) {

        if (row >= 0 && col >= 0 && row < lights.length && 
            col < lights[0].length)
        {
            if (lights[row][col] = true) {
                lights[row][col] = false;
            } else {
                lights[row][col] = true;
            }
        }

    }
}

Answer 1

Your "core" problem is in your toggle method...

if (lights[row][col] = true) {

= is an assignment, so you saying assign true to lights[row][col] and if lights[row][col] == true then do the following...so it's always true.

A simpler method would be to do....

lights[row][col] = !lights[row][col];

no, if's or else's, nice a simple.

You should also have aa look at Painting in AWT and Swing and Performing Custom Painting . You've violate the paint method chain contract (by not calling super.paint )

Instead of overriding paint , you should be using paintComponent AND you should be calling super.paintComponent before you do any custom painting, this will ensure that the Graphics context is nicely prepared for you