JAVA 6x6 grille coloriage jeu

Pour changer la Colour votre JButton, tout d'abord, vous devez garder une chose à l'esprit, toujours utiliser buttonObject.setOpaque(true);, comme très bien conseillé pour moi une fois par @Robin :-). Comme tiré de Java Docs l'appel à setOpaque(true/false)

Sets the background color of this component. The background color 
is used only if the component is opaque

Ici, j'avais modifié un peu votre code et ajouté quelques commentaires sur ce que j'avais ajouté, voyez est-ce ce que vous vouliez.

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

public class ButtonColours extends JFrame
{
    private static ButtonColours buttonColours;
    /*
     * Access Specifier is public, so that they can be 
     * accessed by the ColourDialog class.
     */ 
    public JButton[][] buttons;
    private static final int GRID_SIZE = 600;
    public static final int ROW = 6;
    public static final int COLUMN = 6;
    // Gap between each cell.
    private static final int GAP = 2;
    private static final Color DEFAULT_COLOUR = new Color(100,100,100);
    public static final String DEFAULT_COMMAND = "6";

    // Instance Variable for the ColourDialog class.
    private ColourDialog dialog = null;

    private BufferedReader input;
    private DataInputStream dataInputStream;
    private FileInputStream fileInputStream;
    private String line= "";

    /*
     * Event Handler for each JButton, inside
     * the buttons ARRAY.
     */
    public ActionListener buttonActions = new ActionListener()
    {
        public void actionPerformed(ActionEvent ae)
        {
            JButton button = (JButton) ae.getSource();
            System.out.println(ae.getActionCommand());
            if (dialog != null && dialog.isShowing())
                dialog.dispose();
            dialog = new ColourDialog(buttonColours, "COLOUR CHOOSER", false, button);      
            dialog.setVisible(true);
            button.setBackground(DEFAULT_COLOUR);
            button.setName("6");
        }
    };

    public ButtonColours()
    {
        buttons = new JButton[ROW][COLUMN];
        try
        {
            fileInputStream = new FileInputStream("start.txt");
            dataInputStream = new DataInputStream(fileInputStream);         
            input = new BufferedReader(new InputStreamReader(dataInputStream));
        }
        catch(IOException ioe)
        {
            ioe.printStackTrace();
        }
    }

    /*
     * Instead of explicitly calling getPreferredSize() method
     * we will override that method instead, for good
     * visual appearance fo the Program on different 
     * Platforms, i.e. Windows, MAC OS, LINUX
     */
    public Dimension getPreferredSize()
    {
        return (new Dimension(GRID_SIZE, GRID_SIZE));
    }

    private void readFile()
    {
        int rowNumber = -1;
        int columnNumber = -1;
        try
        {
            while((line = input.readLine()) != null)
            {
                String[] temp = line.split(" ");
                rowNumber = Integer.parseInt(temp[0].substring(1, temp[0].length()));
                columnNumber = Integer.parseInt(temp[1].substring(1, temp[1].length()));
                String colour = temp[2].trim();
                System.out.println("Row is : " + rowNumber);
                System.out.println("Column is : " + columnNumber);
                System.out.println("Colour is : " + colour);
                if (colour.equals("RED") && rowNumber < ROW && columnNumber < COLUMN)   
                {
                    System.out.println("I am working !");
                    buttons[rowNumber][columnNumber].setBackground(Color.RED);
                    buttons[rowNumber][columnNumber].setName("0");
                }
                else if (colour.equals("YELLOW") && rowNumber < ROW && columnNumber < COLUMN)
                {
                    buttons[rowNumber][columnNumber].setBackground(Color.YELLOW);
                    buttons[rowNumber][columnNumber].setName("1");
                }
                else if (colour.equals("BLUE") && rowNumber < ROW && columnNumber < COLUMN)
                {
                    buttons[rowNumber][columnNumber].setBackground(Color.BLUE);
                    buttons[rowNumber][columnNumber].setName("2");
                }
                else if (colour.equals("GREEN") && rowNumber < ROW && columnNumber < COLUMN)
                {
                    buttons[rowNumber][columnNumber].setBackground(Color.GREEN);
                    buttons[rowNumber][columnNumber].setName("3");
                }
                else if (colour.equals("PURPLE") && rowNumber < ROW && columnNumber < COLUMN)
                {
                    buttons[rowNumber][columnNumber].setBackground(new Color(102,0,102));
                    buttons[rowNumber][columnNumber].setName("4");
                }
                else if (colour.equals("BROWN") && rowNumber < ROW && columnNumber < COLUMN)
                {
                    buttons[rowNumber][columnNumber].setBackground(new Color(102,51,0));
                    buttons[rowNumber][columnNumber].setName("5");
                }
            }
        }
        catch(IOException ioe)
        {
            ioe.printStackTrace();
        }
    }

    private void createAndDisplayGUI()
    {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationByPlatform(true);

        JComponent contentPane = (JComponent) getContentPane();
        contentPane.setLayout(new GridLayout(ROW, COLUMN, GAP, GAP));

        for (int i = 0; i < ROW; i++)
        {
            for (int j = 0; j < COLUMN; j++)
            {
                buttons[i][j] = new JButton();
                buttons[i][j].setOpaque(true);
                buttons[i][j].setBackground(DEFAULT_COLOUR);
                buttons[i][j].setActionCommand(i + " " + j);
                buttons[i][j].setName("6");
                buttons[i][j].addActionListener(buttonActions);
                contentPane.add(buttons[i][j]);
            }
        }
        pack();
        setVisible(true);
        readFile();
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                buttonColours = new ButtonColours();
                buttonColours.createAndDisplayGUI();
            }
        });
    }
}

class ColourDialog extends JDialog
{
    private Color[] colours = {
                                                Color.RED, 
                                                Color.YELLOW,
                                                Color.BLUE,
                                                Color.GREEN,
                                                new Color(102,0,102),
                                                new Color(102,51,0)
                                            };
    private int[] colourIndices = new int[6];
    private JButton redButton;
    private JButton yellowButton;
    private JButton blueButton;
    private JButton greenButton;
    private JButton purpleButton;
    private JButton brownButton;

    private JButton clickedButton;
    private int leftRowButtons;
    private int leftColumnButtons;

    public ColourDialog(final ButtonColours frame, String title, boolean isModal, JButton button)
    {
        super(frame, title, isModal);

        leftRowButtons = 0;
        leftColumnButtons = 0;

        clickedButton = button;

        setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        setLocationByPlatform(true);

        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(0, 1, 5, 5));
        panel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));

        redButton = new JButton("RED");
        redButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                String possibleColour = "0";
                /*
                 * Here we will check, if RED is clicked,
                 * do we have any block with the same colour
                 * or not, if yes then nothing will happen
                 * else we will change the background
                 * to RED.
                 */
                if (checkBlockColours(frame, possibleColour))
                {
                    clickedButton.setBackground(Color.RED);
                    clickedButton.setName("0");
                    dispose();
                    System.out.println("LEFT in ROW : " + leftRowButtons);
                    System.out.println("LEFT in COLUMN : " + leftColumnButtons);
                    System.out.println("Button Name : " + clickedButton.getName());
                    fillRemaining(frame);
                }
            }
        });
        yellowButton = new JButton("YELLOW");
        yellowButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                String possibleColour = "1";
                if (checkBlockColours(frame, possibleColour))
                {
                    clickedButton.setBackground(Color.YELLOW);
                    clickedButton.setName("1");
                    dispose();
                    System.out.println("LEFT in ROW : " + leftRowButtons);
                    System.out.println("LEFT in COLUMN : " + leftColumnButtons);
                    System.out.println("Button Name : " + clickedButton.getName());
                    fillRemaining(frame);
                }
            }
        });
        blueButton = new JButton("BLUE");
        blueButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                String possibleColour = "2";
                if (checkBlockColours(frame, possibleColour))
                {
                    clickedButton.setBackground(Color.BLUE);
                    clickedButton.setName("2");
                    dispose();
                    System.out.println("LEFT in ROW : " + leftRowButtons);
                    System.out.println("LEFT in COLUMN : " + leftColumnButtons);
                    System.out.println("Button Name : " + clickedButton.getName());
                    fillRemaining(frame);
                }
            }
        });
        greenButton = new JButton("GREEN");
        greenButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                String possibleColour = "3";
                if (checkBlockColours(frame, possibleColour))
                {
                    clickedButton.setBackground(Color.GREEN);
                    clickedButton.setName("3");
                    dispose();
                    System.out.println("LEFT in ROW : " + leftRowButtons);
                    System.out.println("LEFT in COLUMN : " + leftColumnButtons);
                    System.out.println("Button Name : " + clickedButton.getName());
                    fillRemaining(frame);
                }
            }
        });
        purpleButton = new JButton("PURPLE");
        purpleButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                String possibleColour = "4";
                if (checkBlockColours(frame, possibleColour))
                {
                    clickedButton.setBackground(new Color(102,0,102));
                    clickedButton.setName("4");
                    dispose();
                    System.out.println("LEFT in ROW : " + leftRowButtons);
                    System.out.println("LEFT in COLUMN : " + leftColumnButtons);
                    System.out.println("Button Name : " + clickedButton.getName());
                    fillRemaining(frame);
                }
            }
        });
        brownButton = new JButton("BROWN");
        brownButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                String possibleColour = "5";
                if (checkBlockColours(frame, possibleColour))
                {
                    clickedButton.setBackground(new Color(102,51,0));
                    clickedButton.setName("5");
                    dispose();
                    System.out.println("LEFT in ROW : " + leftRowButtons);
                    System.out.println("LEFT in COLUMN : " + leftColumnButtons);
                    System.out.println("Button Name : " + clickedButton.getName());
                    fillRemaining(frame);
                }
            }
        });

        panel.add(redButton);
        panel.add(yellowButton);
        panel.add(blueButton);
        panel.add(greenButton);
        panel.add(purpleButton);
        panel.add(brownButton);

        add(panel);

        pack();
    }

    private boolean checkBlockColours(ButtonColours frame, String possibleColour)
    {
        leftRowButtons = 0;
        leftColumnButtons = 0;
        String command = clickedButton.getActionCommand();
        String[] array = command.split(" ");
        int row = Integer.parseInt(array[0]);
        int column = Integer.parseInt(array[1]);        
        // First we will check in ROW. for the same colour, that is clicked.
        for (int i = 0; i  < ButtonColours.COLUMN; i++)
        {
            if (i != column)
            {
                JButton button = frame.buttons[row][i];
                if (button.getName().equals(possibleColour))
                    return false;
                else if (button.getName().equals(ButtonColours.DEFAULT_COMMAND))    
                    leftRowButtons++;
            }   
        }
        // Now we will check in COLUMN, for the same colour, that is clicked.
        for (int i = 0; i  < ButtonColours.ROW; i++)
        {
            if (i != row)
            {
                JButton button = frame.buttons[i][column];
                if (button.getName().equals(possibleColour))
                    return false;
                else if     (button.getName().equals(ButtonColours.DEFAULT_COMMAND))    
                    leftColumnButtons++;
            }   
        }
        return true;
    }

    private void fillRemaining(ButtonColours frame)
    {
        String command = clickedButton.getActionCommand();
        String[] array = command.split(" ");
        int row = Integer.parseInt(array[0]);
        int column = Integer.parseInt(array[1]);    
        int emptyRow = -1;
        int emptyColumn = -1;
        if (leftRowButtons == 1)
        {
            for (int i = 0; i  < ButtonColours.COLUMN; i++)
            {
                JButton button = frame.buttons[row][i];
                int colourIndex = Integer.parseInt(button.getName()); 
                switch(colourIndex)
                {
                    case 0:
                        colourIndices[0] = 1;
                        break;
                    case 1:
                        colourIndices[1] = 1;
                        break;
                    case 2:
                        colourIndices[2] = 1;
                        break;
                    case 3:
                        colourIndices[3] = 1;
                        break;
                    case 4:
                        colourIndices[4] = 1;
                        break;
                    case 5:
                        colourIndices[5] = 1;
                        break;
                    default:
                        emptyRow = row;
                        emptyColumn = i;
                }               
            }
            for (int i = 0; i < colourIndices.length; i++)
            {
                if (colourIndices[i] == 0)
                {
                    frame.buttons[emptyRow][emptyColumn].setBackground(colours[i]);
                    setButtonName(frame.buttons[emptyRow][emptyColumn], i);
                    System.out.println("Automatic Button Name : " + frame.buttons[emptyRow][emptyColumn].getName());
                    System.out.println("Automatic Row : " + emptyRow);
                    System.out.println("Automatic Column : " + emptyColumn);
                    disableListenersRow(frame, row);
                    if (checkBlockColours(frame, ButtonColours.DEFAULT_COMMAND))
                    {
                        System.out.println("LEFT in ROW : " + leftRowButtons);
                        System.out.println("LEFT in COLUMN : " + leftColumnButtons);
                        System.out.println("Button Name : " + clickedButton.getName());
                        fillRemaining(frame);
                    }
                    break;
                }
            }
        }
        if (leftColumnButtons == 1)
        {
            for (int i = 0; i  < ButtonColours.ROW; i++)
            {
                JButton button = frame.buttons[i][column];
                int colourIndex = Integer.parseInt(button.getName()); 
                switch(colourIndex)
                {
                    case 0:
                        colourIndices[0] = 1;
                        break;
                    case 1:
                        colourIndices[1] = 1;
                        break;
                    case 2:
                        colourIndices[2] = 1;
                        break;
                    case 3:
                        colourIndices[3] = 1;
                        break;
                    case 4:
                        colourIndices[4] = 1;
                        break;
                    case 5:
                        colourIndices[5] = 1;
                        break;
                    default:
                        emptyRow = i;
                        emptyColumn = column;
                }               
            }
            for (int i = 0; i < colourIndices.length; i++)
            {
                if (colourIndices[i] == 0)
                {
                    frame.buttons[emptyRow][emptyColumn].setBackground(colours[i]);
                    setButtonName(frame.buttons[emptyRow][emptyColumn], i);
                    System.out.println("Automatic Button Name : " + frame.buttons[emptyRow][emptyColumn].getName());
                    System.out.println("Automatic Row : " + emptyRow);
                    System.out.println("Automatic Column : " + emptyColumn);
                    disableListenersColumn(frame, column);
                    if (checkBlockColours(frame, ButtonColours.DEFAULT_COMMAND))
                    {
                        System.out.println("LEFT in ROW : " + leftRowButtons);
                        System.out.println("LEFT in COLUMN : " + leftColumnButtons);
                        System.out.println("Button Name : " + clickedButton.getName());
                        fillRemaining(frame);
                    }
                    break;
                }
            }
        }
    }

    private void setButtonName(JButton button, int index)
    {
        switch(index)
        {
            case 0:
                button.setName("0");
                break;
            case 1:
                button.setName("1");
                break;
            case 2:     
                button.setName("2");
                break;
            case 3:
                button.setName("3");
                break;
            case 4:
                button.setName("4");
                break;
            case 5:
                button.setName("5");
                break;
        }       
    }

    private void disableListenersRow(ButtonColours frame, int row)
    {
        System.out.println("Disabled ROW : " + row);        
        for (int i = 0; i < ButtonColours.ROW; i++)
        {
            frame.buttons[row][i].removeActionListener(frame.buttonActions);
            System.out.println("DISABLED BUTTONS : " + row + " " + i);
        }           
    }

    private void disableListenersColumn(ButtonColours frame, int column)
    {
        System.out.println("Disabled COLUMN : " + column);
        for (int i = 0; i < ButtonColours.COLUMN; i++)
        {
            frame.buttons[i][column].removeActionListener(frame.buttonActions);
            System.out.println("DISABLED BUTTONS : " + i + " " + column);
        }
    }
}

Voici la sortie de ce truc :-)