Question

Coding a game of Connect four with a 6 x 7 grid. It will use colored output to show where pieces have been put already.

Answer 1

Please let me know if you have any doubts or you want me to modify the code. And if you find this code useful then don't forget to rate my answer as thumps up. Thank you! :)

public class ConnectFourMain {
    public static void main(String[] args) {
        @SuppressWarnings("unused")
        ConnectFourGui gui = new ConnectFourGui();
    }

}
-------------------------------------------------------------------------------------
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingConstants;

public class ConnectFourGui extends JFrame {

    private static final long serialVersionUID = 1L;
    private JLabel title;
    private JButton[] buttons;
    private JLabel[][] board;
    private JButton reset;
    private BlinkLabel blinker;

    private ImageIcon arrow;
    private ImageIcon emptySlot;
    private ImageIcon redSlot;
    private ImageIcon blackSlot;

    private int player;
    private boolean isWinner;

    public ConnectFourGui() {

        setTitle("Connect Four");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(7, 7));
        panel.setBackground(Color.YELLOW);

        JPanel panel2 = new JPanel();
        panel2.setBackground(Color.BLACK);

        JPanel panelTop = new JPanel();
        panelTop.setLayout(new BorderLayout());

        this.title = new JLabel("Connect Four");
        title.setForeground(Color.RED);
        title.setFont(new Font("Sans-Serif", Font.BOLD, 50));
        title.setHorizontalAlignment(SwingConstants.CENTER);

        Board gameBoard = new Board();
        player = 1;
        isWinner = false;

        arrow = new ImageIcon("arrowButton.png");
        emptySlot = new ImageIcon("emptySlot.png");
        redSlot = new ImageIcon("redSlot.png");
        blackSlot = new ImageIcon("blackSlot.png");
        buttons = new JButton[7];
        board = new JLabel[6][7];
        reset = new JButton("RESTART");
        blinker = new BlinkLabel("");

        reset.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent a){
                gameBoard.reset();
                player = 1;
                title.setText("Connect Four");
                blinker.setBlinking(false);
                blinker.setText("");

                for (int i = 0; i < 6; i++){
                    for (int j = 0; j < 7; j++){
                        board[i][j].setIcon(emptySlot);
                    }
                }
            }
        });

        for (int i = 0; i < 7; i++) {
            int column = i;
            this.buttons[i] = new JButton(arrow);
            buttons[i].setBackground(Color.WHITE);
            panel.add(buttons[i]);
            buttons[i].addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent a) {
                    if (player == 1) {
                        player = 2;
                        try {
                            gameBoard.move(1, column);
                            for (int k = 5; k >= 0; k--) {
                                if (board[k][column].getIcon() == emptySlot) {
                                    board[k][column].setIcon(redSlot);
                                    isWinner = gameBoard.isWinner();
                                    if (isWinner == true) {
                                        title.setText("");
                                        blinker.setText("RED IS WINNER!");
                                        panel2.add(blinker, BorderLayout.CENTER);
                                        blinker.setBlinking(true);
                                    }
                                    break;
                                }
                            }
                        } catch (NoEmptySpaceColumnException e) {
                            player = 1;
                        }

                    } else {
                        player = 1;
                        try {
                            gameBoard.move(2, column);
                            for (int k = 5; k >= 0; k--) {
                                if (board[k][column].getIcon() == emptySlot) {
                                    board[k][column].setIcon(blackSlot);
                                    isWinner = gameBoard.isWinner();
                                    if (isWinner == true) {
                                        title.setText("");
                                        blinker.setText("BLACK IS WINNER!");
                                        panel2.add(blinker, BorderLayout.CENTER);
                                        blinker.setBlinking(true);
                                    }
                                    break;
                                }
                            }
                        } catch (NoEmptySpaceColumnException e) {
                            player = 2;
                        }
                    }
                }
            });
        }
        for (int i = 0; i < 6; i++){
            for (int j = 0; j < 7; j++){
                board[i][j] = new JLabel(emptySlot);
                panel.add(board[i][j]);
            }
        }
        panel2.add(reset, BorderLayout.WEST);
        panel2.add(title, BorderLayout.CENTER);

        panelTop.add(panel2, BorderLayout.NORTH);
        panelTop.add(panel, BorderLayout.CENTER);

        getContentPane().add(panelTop);
        pack();
        setLocationRelativeTo(null);
        setVisible(true);
    }

}
------------------------------------------------------------------------------------
public class Board {

    private int[][] gameBoard;

    public Board() {
        gameBoard = new int[6][7];
    }

    public void move(int player, int column) throws NoEmptySpaceColumnException {

        // check if column is full
        if (gameBoard[0][column] != 0) {
            throw new NoEmptySpaceColumnException();
        }

        // if column is partially full- put in bottom most
        // available space
        else {
            for (int i = 5; i >= 0; i--) {
                if (gameBoard[i][column] == 0) {
                    gameBoard[i][column] = player;
                    break;
                }
            }
        }
    }

    public boolean isWinner() {
        boolean winner = false;

        // check if four values are consecutive horizontally
        for (int row = 0; row < gameBoard.length; row++) {
            for (int column = 0; column < gameBoard[row].length - 3; column++) {
                if (gameBoard[row][column] == gameBoard[row][column + 1]
                        && gameBoard[row][column + 1] == gameBoard[row][column + 2]
                        && gameBoard[row][column + 2] == gameBoard[row][column + 3] && gameBoard[row][column] != 0) {
                    winner = true;
                    break;
                }
            }
        }

        // check if four values are consecutive vertically
        if (winner == false) {
            for (int row = 0; row < gameBoard.length - 3; row++) {
                for (int column = 0; column < gameBoard[row].length; column++) {

                    if (gameBoard[row][column] == gameBoard[row + 1][column]
                            && gameBoard[row + 1][column] == gameBoard[row + 2][column]
                            && gameBoard[row + 2][column] == gameBoard[row + 3][column]
                            && gameBoard[row][column] != 0) {
                        winner = true;
                        break;
                    }
                }
            }
        }

        // check if four values are diagonal
        if (winner == false) {
            for (int row = 0; row < gameBoard.length - 3; row++) {
                for (int column = 0; column < gameBoard[row].length - 3; column++) {

                    if ((gameBoard[row][column] == gameBoard[row + 1][column + 1]
                            && gameBoard[row + 1][column + 1] == gameBoard[row + 2][column + 2]
                            && gameBoard[row + 2][column + 2] == gameBoard[row + 3][column + 3]
                            && gameBoard[row][column] != 0)|| (gameBoard[row][column + 3] == gameBoard[row + 1][column + 2]
                            && gameBoard[row + 1][column + 2] == gameBoard[row + 2][column + 1]
                            && gameBoard[row + 2][column + 1] == gameBoard[row + 3][column]
                            && gameBoard[row][column+3] != 0)) {
                        winner = true;
                        break;
                    }
                }
            }
        }
        return winner;
    }

    public void display() {
        for (int i = 0; i < 6; i++) {
            for (int j = 0; j < 7; j++) {
                System.out.print(gameBoard[i][j]);
            }
            System.out.print("\n");
        }
    }

    public void reset() {
        for (int i = 0; i < 6; i++) {
            for (int j = 0; j < 7; j++) {
                gameBoard[i][j] = 0;
            }
        }
    }

}
-----------------------------------------------------------------------------------
public class NoEmptySpaceColumnException extends Exception {

    private static final long serialVersionUID = 1L;

    public NoEmptySpaceColumnException(){
        super("All spots in column filled.");
    }

}
----------------------------------------------------------------------------------
import java.awt.Color;
import java.awt.Font;
import java.awt.event.*;

import javax.swing.*;

public class BlinkLabel extends JLabel {
    private static final long serialVersionUID = 1L;

    private final int BLINKING_RATE = 500;

    private boolean blinkingOn = true;

    public BlinkLabel(String text) {
        super(text);
        Timer timer = new Timer( BLINKING_RATE , new TimerListener(this));
        timer.setInitialDelay(0);
        timer.start();
    }

    public void setBlinking(boolean flag) {
        this.blinkingOn = flag;
    }
    public boolean getBlinking(boolean flag) {
        return this.blinkingOn;
    }

    private class TimerListener implements ActionListener {
        private BlinkLabel bl;
        private Color bg;
        private Color fg;
        private boolean isForeground = true;

        public TimerListener(BlinkLabel bl) {
            this.bl = bl;
            fg = Color.RED;
            bg = Color.BLACK;
            this.bl.setFont(new Font("Sans-Serif", Font.BOLD, 50));
        }

        public void actionPerformed(ActionEvent e) {
            if (bl.blinkingOn) {
                if (isForeground) {
                    bl.setForeground(fg);
                }
                else {
                    bl.setForeground(bg);
                }
                isForeground = !isForeground;
            }
            else {
                if (isForeground) {
                    bl.setForeground(fg);
                    isForeground = false;
                }
            }
        }

    }}