Minesweeper in Java

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This tutorial gives a brief overview of what to do to get a small, graphical Minesweeper game running on your Overo. If you have not done so, please go through the tutorials Eclipse on Gumstix for new users and HelloWorld in Java.

This does not explain the game of MineSweeper, rather just lets use utilize the code to see an example of the graphical possibilities using an Overo COM.

  • Create a new Project in Eclipse
  • File -> New Project -> Java Project
  • Create a class Main Class
  • Copy and paste the following code to that class:
  
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JColorChooser;
import javax.swing.JFrame;
import javax.swing.JOptionPane;

public class MainClass {
  public static void main(String args[]) {
    JFrame f = new JFrame("JColorChooser Sample");
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    final JButton button = new JButton("Pick to Change Background");

    ActionListener actionListener = new ActionListener() {
      public void actionPerformed(ActionEvent actionEvent) {
        Color initialBackground = button.getBackground();
        Color background = JColorChooser.showDialog(null,
            "JColorChooser Sample", initialBackground);
        if (background != null) {
          button.setBackground(background);
        }
      }
    };
    button.addActionListener(actionListener);
    f.add(button, BorderLayout.CENTER);
    f.setSize(300, 200);
    f.setVisible(true);
  }

}
  • Create a class MineSweeper (Capital S!)
  • Copy and paste the following code to that class:
import java.awt.AWTEvent;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.Insets;
import java.awt.Point;
import java.awt.Toolkit;
import java.awt.event.AWTEventListener;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;

public class MineSweeper extends JPanel implements AWTEventListener, ActionListener {

	  public static enum State {
	    Clicked, Marked, Initial, WrongMarked
	  }

	  public static enum GameState {
	    NotStarted, Playing, Finished
	  }

	  private static final int  MAX_BOMB_COUNT  = 10;
	  private int          ROWS      = 9, COLUMNS = 9, TOTAL = ROWS * COLUMNS;
	  private JPanel        pnlMain      = new JPanel(new GridLayout(ROWS, COLUMNS));
	  private JLabel        lblBombCount  = new JLabel(MAX_BOMB_COUNT + "");
	  private JLabel        lblTimer    = new JLabel("0");
	  private boolean        isColorCheatOn  = false;
	  private JButton        btnReset    = new JButton("Reset");

	  private void startThread() {
	    Thread th = new Thread(new Runnable() {
	      public void run() {
	        while (state == GameState.Playing) {
	          lblTimer.setText((Long.parseLong(lblTimer.getText()) + 1) + "");
	          lblTimer.updateUI();
	          try {
	            Thread.sleep(1000);
	          } catch (InterruptedException e) {
	            e.printStackTrace();
	          }
	        }
	      }
	    });
	    th.start();
	  }

	  private GameState  state  = GameState.NotStarted;

	  public MineSweeper() {
	    setLayout(new BorderLayout());
	    add(pnlMain, BorderLayout.CENTER);
	    createButtons();
	    addControlPanel();
	    Toolkit.getDefaultToolkit().addAWTEventListener(this, AWTEvent.KEY_EVENT_MASK);
	  }

	  private void showAbout() {
	    JOptionPane.showMessageDialog(this, "<html>Author : Justin Cowles Cowperthwaite <br>Version : 1.0</html>", "About", JOptionPane.INFORMATION_MESSAGE);
	  }

	  private void restartGame() {
	    state = GameState.NotStarted;
	    lblTimer.setText("0");
	    pnlMain.removeAll();
	    createButtons();
	    pnlMain.updateUI();
	    lblBombCount.setText("" + MAX_BOMB_COUNT);
	    lblBombCount.updateUI();
	  }

	  private void addControlPanel() {
	    JPanel pnlTimer = new JPanel(new FlowLayout(FlowLayout.RIGHT));

	    pnlTimer.add(lblTimer);

	    JPanel pnl = new JPanel(new FlowLayout(FlowLayout.CENTER));

	    btnReset.setToolTipText("<HTML>Press <B>F2</B> to reset the current game</HTML>");
	    pnl.add(lblBombCount);
	    pnl.add(btnReset);
	    JPanel pnlN = new JPanel(new GridLayout(1, 3));

	    pnlN.add(lblBombCount);
	    pnlN.add(pnl);
	    pnlN.add(pnlTimer);
	    add(pnlN, BorderLayout.NORTH);
	    btnReset.addActionListener(this);
	  }

	  private void createButtons() {
	    List<Point> lstBombsLocation = new ArrayList<Point>();

	    for (int row = 0; row < ROWS; row++) {
	      for (int col = 0; col < COLUMNS; col++) {
	        JButton btn = getButton(lstBombsLocation, TOTAL, new Point(row, col) {
	          @Override
	          public String toString() {
	            return (int) getX() + ", " + (int) getY();
	          }

	          @Override
	          public boolean equals(Object obj) {
	            return ((Point) obj).getX() == getX() && ((Point) obj).getY() == getY();
	          }
	        });
	        pnlMain.add(btn);
	      }
	    }
	    while (lstBombsLocation.size() < MAX_BOMB_COUNT) {
	      updateBomds(lstBombsLocation, pnlMain.getComponents());
	    }
	    for (Component c : pnlMain.getComponents()) {
	      updateBombCount((GameButton) c, pnlMain.getComponents());
	    }
	    // System.out.println("Total Bomb Count: " + lstBombsLocation.size());
	  }

	  private void updateBomds(List<Point> lstBombsLocation, Component[] components) {
	    // int currentPosition = new Double(((location.x) * COLUMNS ) +
	    // location.getY()).intValue();
	    Random r = new Random();
	    for (Component c : components) {
	      Point location = ((GameButton) c).getPosition();
	      int currentPosition = new Double(((location.x) * COLUMNS) + location.getY()).intValue();
	      int bombLocation = r.nextInt(TOTAL);
	      if (bombLocation == currentPosition) {
	        ((GameButton) c).setBomb(true);
	        lstBombsLocation.add(((GameButton) c).getPosition());
	        return;
	      }
	    }
	  }

	  private GameButton getButton(List<Point> lstBombsLocation, int totalLocations, Point location) {
	    GameButton btn = new GameButton(location);
	    btn.setMargin(new Insets(0, 0, 0, 0));
	    btn.setFocusable(false);
	    if (lstBombsLocation.size() < MAX_BOMB_COUNT) {
	      if (isBomb()) {
	        btn.setBomb(true);
	        lstBombsLocation.add(location);
	      }
	    }
	    btn.addMouseListener(new MouseAdapter() {
	      @Override
	      public void mouseClicked(MouseEvent mouseEvent) {
	        if (state != GameState.Playing) {
	          state = GameState.Playing;
	          startThread();
	        }
	        if (((GameButton) mouseEvent.getSource()).isEnabled() == false) {
	          return;
	        }
	        if (mouseEvent.getButton() == MouseEvent.BUTTON1) {
	          if (((GameButton) mouseEvent.getSource()).getState() == State.Marked) {
	            ((GameButton) mouseEvent.getSource()).setState(State.Initial);
	            lblBombCount.setText((Long.parseLong(lblBombCount.getText()) + 1) + "");
	            ((GameButton) mouseEvent.getSource()).updateUI();
	            return;
	          }
	          ((GameButton) mouseEvent.getSource()).setState(State.Clicked);
	          if (((GameButton) mouseEvent.getSource()).isBomb()) {
	            blastBombs();
	            return;
	          } else {
	            if (((GameButton) mouseEvent.getSource()).getBombCount() == 0) {
	              updateSurroundingZeros(((GameButton) mouseEvent.getSource()).getPosition());
	            }
	          }
	          if (!checkGameState()) {
	            ((GameButton) mouseEvent.getSource()).setEnabled(false);
	          }
	        } else if (mouseEvent.getButton() == MouseEvent.BUTTON3) {
	          if (((GameButton) mouseEvent.getSource()).getState() == State.Marked) {
	            ((GameButton) mouseEvent.getSource()).setState(State.Initial);
	            lblBombCount.setText((Long.parseLong(lblBombCount.getText()) + 1) + "");
	          } else {
	            ((GameButton) mouseEvent.getSource()).setState(State.Marked);
	            lblBombCount.setText((Long.parseLong(lblBombCount.getText()) - 1) + "");
	          }
	        }
	        ((GameButton) mouseEvent.getSource()).updateUI();
	      }
	    });
	    return btn;
	  }

	  private boolean checkGameState() {
	    boolean isWin = false;
	    for (Component c : pnlMain.getComponents()) {
	      GameButton b = (GameButton) c;
	      if (b.getState() != State.Clicked) {
	        if (b.isBomb()) {
	          isWin = true;
	        } else {
	          return false;
	        }
	      }
	    }
	    if (isWin) {
	      state = GameState.Finished;
	      for (Component c : pnlMain.getComponents()) {
	        GameButton b = (GameButton) c;
	        if (b.isBomb()) {
	          b.setState(State.Marked);
	        }
	        b.setEnabled(false);

	      }
	      JOptionPane.showMessageDialog(this, "You win the game :D", "Congrats", JOptionPane.INFORMATION_MESSAGE, null);
	    }
	    return isWin;
	  }

	  private void updateSurroundingZeros(Point currentPoint) {
	    Point[] points = getSurroundings(currentPoint);

	    for (Point p : points) {
	      GameButton b = getButtonAt(pnlMain.getComponents(), p);
	      if (b != null && b.getBombCount() == 0 && b.getState() != State.Clicked && b.getState() != State.Marked && b.isBomb() == false) {
	        b.setState(State.Clicked);
	        updateSurroundingZeros(b.getPosition());
	        b.updateUI();
	      }
	      if (b != null && b.getBombCount() > 0 && b.getState() != State.Clicked && b.getState() != State.Marked && b.isBomb() == false) {
	        b.setEnabled(false);
	        b.setState(State.Clicked);
	        b.updateUI();
	      }
	    }
	  }

	  private void blastBombs() {
	    int blastCount = 0;
	    for (Component c : pnlMain.getComponents()) {
	      ((GameButton) c).setEnabled(false);
	      ((GameButton) c).transferFocus();
	      if (((GameButton) c).isBomb() && ((GameButton) c).getState() != State.Marked) {
	        ((GameButton) c).setState(State.Clicked);
	        ((GameButton) c).updateUI();
	        blastCount++;
	      }
	      if (((GameButton) c).isBomb() == false && ((GameButton) c).getState() == State.Marked) {
	        ((GameButton) c).setState(State.WrongMarked);
	      }
	    }
	    lblBombCount.setText("" + blastCount);
	    lblBombCount.updateUI();
	    state = GameState.Finished;
	    JOptionPane.showMessageDialog(this, "You loose the game :(", "Game Over", JOptionPane.ERROR_MESSAGE, null);
	    for (Component c : pnlMain.getComponents()) {
	      GameButton b = (GameButton) c;
	      b.setEnabled(false);
	    }
	  }

	  private boolean isBomb() {
	    Random r = new Random();
	    return r.nextInt(ROWS) == 1;
	  }

	  public static void main(String[] args) {
	    JFrame fr = new JFrame("MineSweeper");
	    fr.setLayout(new BorderLayout());
	    fr.add(new MineSweeper());
	    fr.setResizable(false);
	    fr.setSize(250, 350);
	    fr.setLocationRelativeTo(null);
	    fr.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	    fr.setVisible(true);
	  }

	  class GameButton extends JButton {
	    private boolean  isBomb    = false;
	    private Point  position  = null;
	    private int    bombCount  = 0;
	    private State  state    = State.Initial;

	    public void setState(State state) {
	      this.state = state;
	      if (getBombCount() == 0 && !isBomb) {
	        setEnabled(false);
	      }
	    }

	    public State getState() {
	      return state;
	    }

	    public int getBombCount() {
	      return bombCount;
	    }

	    public void setBombCount(int bombCount) {
	      this.bombCount = bombCount;
	    }

	    public GameButton(Point position) {
	      setPosition(position);
	      setText(position.toString());
	    }

	    public Point getPosition() {
	      return position;
	    }

	    public void setPosition(Point position) {
	      this.position = position;
	    }

	    public boolean isBomb() {
	      return isBomb;
	    }

	    public void setBomb(boolean isBomb) {
	      this.isBomb = isBomb;
	    }

	    @Override
	    public String getText() {
	      if (state == State.Initial) {
	        return "";
	      }
	      if (state == State.Marked) {
	        return "\u00B6";
	      }
	      if (state == State.Clicked) {
	        if (isBomb) {
	          return "<html><font size='16'><b>*</b></font></html>";
	        } else {
	          if (getBombCount() > 0)
	            return getBombCount() + "";
	          else
	            return "";
	        }
	      }
	      if (state == State.WrongMarked) {
	        return "X";
	      }
	      return super.getText();
	    }

	    @Override
	    public Color getBackground() {
	      if (isColorCheatOn && isBomb) {
	        return Color.MAGENTA;
	      }
	      if (state == State.Clicked) {
	        if (isBomb) {
	          return Color.RED;
	        }
	        if (getBombCount() > 0) {
	          return Color.GREEN;
	        }
	      }
	      if (isEnabled()) {
	        return Color.YELLOW.brighter();
	      } else {
	        return super.getBackground();
	      }
	    }
	  }

	  private Point[] getSurroundings(Point cPoint) {
	    int cX = (int) cPoint.getX();
	    int cY = (int) cPoint.getY();
	    Point[] points = { new Point(cX - 1, cY - 1), new Point(cX - 1, cY), new Point(cX - 1, cY + 1), new Point(cX, cY - 1), new Point(cX, cY + 1), 
                                         new Point(cX + 1, cY - 1), new Point(cX + 1, cY), new Point(cX + 1, cY + 1) };
	    return points;
	  }

	  private void updateBombCount(GameButton btn, Component[] components) {
	    Point[] points = getSurroundings(btn.getPosition());

	    for (Point p : points) {
	      GameButton b = getButtonAt(components, p);
	      if (b != null && b.isBomb()) {
	        btn.setBombCount(btn.getBombCount() + 1);
	      }
	    }
	    btn.setText(btn.getBombCount() + "");
	  }

	  private GameButton getButtonAt(Component[] components, Point position) {
	    for (Component btn : components) {
	      if ((((GameButton) btn).getPosition().equals(position))) {
	        return (GameButton) btn;
	      }
	    }
	    return null;
	  }

	  public void eventDispatched(AWTEvent event) {
	    if (KeyEvent.class.isInstance(event) && ((KeyEvent) (event)).getID() == KeyEvent.KEY_RELEASED) {
	      if (((KeyEvent) (event)).getKeyCode() == KeyEvent.VK_F1) {
	        showAbout();
	      }
	      if (((KeyEvent) (event)).getKeyCode() == KeyEvent.VK_F2) {
	        restartGame();
	      }
	      if (((KeyEvent) (event)).getKeyCode() == KeyEvent.VK_F3) {
	        isColorCheatOn = !isColorCheatOn;
	        if (state == GameState.Playing) {
	          pnlMain.updateUI();
	        }
	      }

	      if (((KeyEvent) (event)).getKeyCode() == KeyEvent.VK_F12) {
	        for (Component c : pnlMain.getComponents()) {
	          GameButton b = (GameButton) c;
	          if (b.isBomb() == false) {
	            b.setState(State.Clicked);
	          } else {
	            b.setState(State.Marked);
	          }
	          b.setEnabled(false);
	        }
	        checkGameState();
	      }
	    }
	  }

	  public void actionPerformed(ActionEvent actionEvent) {
	    if (actionEvent.getSource() == btnReset) {
	      restartGame();
	    }
	  }
	}

Go back to HelloWorld in Java and follow the instructions for Exporting and Running a Java Program on the Over COM. When you are done, you should be able to play a 9x10 colorful game of MineSweeper on the monitor connected to your Overo COM expansion board.