java - Java 贪吃蛇游戏

Question

我正在开发一个蛇程序。到目前为止，我有两个类，一个用于游戏的所有逻辑，另一个作为运行游戏的主类。这是我所拥有的

蛇类:

这是所有常量

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

public class Snake {
// GUI components
private JPanel board;
private JButton[] snakeBodyPart;
private JButton bonusfood;
private JTextArea scoreViewer;

// Constants
private final int SNAKE_RUNNING_SPEED_FASTEST = 25;
private final int SNAKE_RUNNING_SPEED_FASTER = 50;
private final int SNAKE_RUNNING_SPEED_FAST = 100;
private final int BOARD_WIDTH = 500;
private final int BOARD_HEIGHT = 250;
private final int SCORE_BOARD_HEIGHT = 20;
private final int SNAKE_LENGTH_DEFAULT = 4;
private final int SNAKE_BODY_PART_SQURE = 10;
private final int BONUS_FOOD_SQURE = 15;
private final Point INIT_POINT = new Point(100, 150);

// Others values
private enum GAME_TYPE {NO_MAZE, BORDER, TUNNEL};
private int selectedSpeed = SNAKE_RUNNING_SPEED_FASTER;
private GAME_TYPE selectedGameType = GAME_TYPE.NO_MAZE;
private int totalBodyPart;
private int directionX;
private int directionY;
private int score;
private Point pointOfBonusFood = new Point();
private boolean isRunningLeft;
private boolean isRunningRight;
private boolean isRunningUp;
private boolean isRunningDown;
private boolean isBonusFoodAvailable;
private boolean isRunning;
private Random random = new Random();

这是游戏开始的地方

Snake() {
    //initialize all variables.
    resetDefaultValues();
    // initialize GUI.
    init();
    // Create Initial body of a snake.
    createInitSnake();
    // Initialize Thread.
    isRunning = true;
    createThread();
}

这是设置董事会的地方

public void init() {
    JFrame frame = new JFrame("Snake");
    frame.setSize(500, 330);

    //Create Menue bar with functions
    setJMenueBar(frame);
    // Start of UI design
    JPanel scorePanel = new JPanel();
    scoreViewer = new JTextArea("Score ==>" + score);
    scoreViewer.setEnabled(false);
    scoreViewer.setBackground(Color.BLACK);

    board = new JPanel();
    board.setLayout(null);
    board.setBounds(0, 0, BOARD_WIDTH, BOARD_HEIGHT);
    board.setBackground(Color.WHITE);
    scorePanel.setLayout(new GridLayout(0, 1));
    scorePanel.setBounds(0, BOARD_HEIGHT, BOARD_WIDTH, SCORE_BOARD_HEIGHT);
    scorePanel.setBackground(Color.RED);
    scorePanel.add(scoreViewer); // will contain score board

    frame.getContentPane().setLayout(null);
    frame.getContentPane().add(board);
    frame.getContentPane().add(scorePanel);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.addKeyListener(new KeyAdapter() {
        @Override
        public void keyPressed(KeyEvent e) {
            snakeKeyPressed(e);
        }
    });
    frame.setResizable(false);
}

这是菜单

public void setJMenueBar(JFrame frame) {

    JMenuBar mymbar = new JMenuBar();

    JMenu game = new JMenu("Game");
    JMenuItem newgame = new JMenuItem("New Game");
    JMenuItem exit = new JMenuItem("Exit");
    newgame.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            startNewGame();
        }
    });
    exit.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            System.exit(0);
        }
    });
    game.add(newgame);
    game.addSeparator();
    game.add(exit);
    mymbar.add(game);

    JMenu type = new JMenu("Type");
    JMenuItem noMaze = new JMenuItem("No Maze");
    noMaze.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            selectedGameType = GAME_TYPE.NO_MAZE;
            startNewGame();
        }
    });
    JMenuItem border = new JMenuItem("Border Maze");
    border.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            selectedGameType = GAME_TYPE.BORDER;
            startNewGame();
        }
    });
    type.add(noMaze);
    type.add(border);
    mymbar.add(type);

    JMenu level = new JMenu("Level");
    JMenuItem level1 = new JMenuItem("Level 1");
    level1.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            selectedSpeed = SNAKE_RUNNING_SPEED_FAST;
            startNewGame();
        }
    });
    JMenuItem level2 = new JMenuItem("Level 2");
    level2.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            selectedSpeed = SNAKE_RUNNING_SPEED_FASTER;
            startNewGame();
        }
    });
    JMenuItem level3 = new JMenuItem("Level 3");
    level3.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            selectedSpeed = SNAKE_RUNNING_SPEED_FASTEST;
            startNewGame();
        }
    });
    level.add(level1);
    level.add(level2);
    level.add(level3);
    mymbar.add(level);

    JMenu help = new JMenu("Help");
    JMenuItem creator = new JMenuItem("Creator");
    JMenuItem instruction = new JMenuItem("Instraction");
    creator.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {                
            JOptionPane.showMessageDialog(null, "Author: Jack Moffe");
        }
    });

    help.add(creator);
    help.add(instruction);
    mymbar.add(help);

    frame.setJMenuBar(mymbar);
}

这会重置所有值

public void resetDefaultValues() {
    snakeBodyPart = new JButton[2000];
    totalBodyPart = SNAKE_LENGTH_DEFAULT;
    directionX = SNAKE_BODY_PART_SQURE;
    directionY = 0;
    score = 0;
    isRunningLeft = false;
    isRunningRight = true;
    isRunningUp = true;
    isRunningDown = true;
    isBonusFoodAvailable = false;
}

void startNewGame() {
    resetDefaultValues();
    board.removeAll();
    createInitSnake();
    scoreViewer.setText("Score==>" + score);
    isRunning = true;
}

该方法负责初始化蛇的四个 body 部位。

public void createInitSnake() {
    // Location of the snake's head.
    int x = (int) INIT_POINT.getX();
    int y = (int) INIT_POINT.getY();

    // Initially the snake has three body part.
    for (int i = 0; i < totalBodyPart; i++) {
        snakeBodyPart[i] = new JButton();            
        snakeBodyPart[i].setBounds(x, y, SNAKE_BODY_PART_SQURE, SNAKE_BODY_PART_SQURE);
        snakeBodyPart[i].setBackground(Color.GRAY);
        board.add(snakeBodyPart[i]);
        // Set location of the next body part of the snake.
        x = x - SNAKE_BODY_PART_SQURE;
    }

    // Create food.
    createFood();
}

这个方法负责创建蛇的食物。这条蛇的最后一部分被当作了食物，还没有成为蛇的 body 部分。当且仅当蛇头接触到该食物时，该食物才是 body 的一部分。

void createFood() {
    int randomX = SNAKE_BODY_PART_SQURE + (SNAKE_BODY_PART_SQURE * random.nextInt(48));
    int randomY = SNAKE_BODY_PART_SQURE + (SNAKE_BODY_PART_SQURE * random.nextInt(23));

    snakeBodyPart[totalBodyPart] = new JButton();
    snakeBodyPart[totalBodyPart].setEnabled(false);
    snakeBodyPart[totalBodyPart].setBounds(randomX, randomY, SNAKE_BODY_PART_SQURE, SNAKE_BODY_PART_SQURE);
    board.add(snakeBodyPart[totalBodyPart]);

    totalBodyPart++;
}

private void createBonusFood() {
    bonusfood = new JButton();
    bonusfood.setEnabled(false);
    //Set location of the bonus food.
    int bonusFoodLocX = SNAKE_BODY_PART_SQURE * random.nextInt(50);
    int bonusFoodLocY = SNAKE_BODY_PART_SQURE * random.nextInt(25);

    bonusfood.setBounds(bonusFoodLocX, bonusFoodLocY, BONUS_FOOD_SQURE, BONUS_FOOD_SQURE);
    pointOfBonusFood = bonusfood.getLocation();
    board.add(bonusfood);
    isBonusFoodAvailable = true;
}

处理蛇的下一步。并决定应该做什么。即蛇在做什么以及如何响应

void processNextStep() {
    boolean isBorderTouched = false;
    // Generate new location of snake head.
    int newHeadLocX = (int) snakeBodyPart[0].getLocation().getX() + directionX;
    int newHeadLocY = (int) snakeBodyPart[0].getLocation().getY() + directionY;

    // Most last part of the snake is food.
    int foodLocX = (int) snakeBodyPart[totalBodyPart - 1].getLocation().getX();
    int foodLocY = (int) snakeBodyPart[totalBodyPart - 1].getLocation().getY();

    // Check does snake cross the border of the board?
    if (newHeadLocX >= BOARD_WIDTH - SNAKE_BODY_PART_SQURE) {
        newHeadLocX = 0;
        isBorderTouched = true;
    } else if (newHeadLocX <= 0) {
        newHeadLocX = BOARD_WIDTH - SNAKE_BODY_PART_SQURE;
        isBorderTouched = true;
    } else if (newHeadLocY >= BOARD_HEIGHT - SNAKE_BODY_PART_SQURE) {
        newHeadLocY = 0;
        isBorderTouched = true;
    } else if (newHeadLocY <= 0) {
        newHeadLocY = BOARD_HEIGHT - SNAKE_BODY_PART_SQURE;
        isBorderTouched = true;
    }

    // Check has snake touched the food?
    if (newHeadLocX == foodLocX && newHeadLocY == foodLocY) {
        // Set score.
        score += 5;
        scoreViewer.setText("Score==>" + score);

        // Check bonus food should be given or not?
        if (score % 50 == 0 && !isBonusFoodAvailable) {
            createBonusFood();
        }
        // Create new food.
        createFood();
    }

    // Check has snake touched the bonus food?
    if (isBonusFoodAvailable &&
            pointOfBonusFood.x <= newHeadLocX &&
            pointOfBonusFood.y <= newHeadLocY &&
            (pointOfBonusFood.x + SNAKE_BODY_PART_SQURE) >= newHeadLocX &&
            (pointOfBonusFood.y + SNAKE_BODY_PART_SQURE) >= newHeadLocY) {
        board.remove(bonusfood);
        score += 100;
        scoreViewer.setText("Score ==>" + score);
        isBonusFoodAvailable = false;
    }

    // Check is game over?
    if(isGameOver(isBorderTouched, newHeadLocX, newHeadLocY)) {
       scoreViewer.setText("GAME OVER   " + score);
       isRunning = false;
       return;
    } else {
        // Move the whole snake body to forword.
        moveSnakeForword(newHeadLocX, newHeadLocY);
    }

    board.repaint();
}

这个方法负责检测游戏是否结束？当蛇被任何迷宫或自身触及时，游戏应该结束。

private boolean isGameOver(boolean isBorderTouched, int headLocX, int headLocY) {
    switch(selectedGameType) {
        case BORDER:
            if(isBorderTouched) {
                return true;
            }
            break;
        case TUNNEL:
            // TODO put logic here...
            throw new UnsupportedOperationException();
        default:
            break;
    }

    for (int i = SNAKE_LENGTH_DEFAULT; i < totalBodyPart - 2; i++) {
        Point partLoc = snakeBodyPart[i].getLocation();
        System.out.println("("+partLoc.x +", "+partLoc.y+")  ("+headLocX+", "+headLocY+")");
        if (partLoc.equals(new Point(headLocX, headLocY))) {
            return true;
        }
    }

    return false;
}

/**
 * Every body part should be placed to location of the front part.
 * For example if part:0(100,150) , part: 1(90, 150), part:2(80,150) and new head location (110,150) then,
   Location of part:2 should be (80,150) to (90,150), part:1 will be (90,150) to (100,150) and part:3 will be (100,150) to (110,150)
 * This movement process should be start from the last part to first part.
 * We must avoid the food that means most last body part of the snake.
 * Notice that we write (totalBodyPart - 2) instead of (totalBodyPart - 1).
 * (totalBodyPart - 1) means food and (totalBodyPart - 2) means tail.
 * @param headLocX
 * @param headLocY
 */
public void moveSnakeForword(int headLocX, int headLocY) {
    for (int i = totalBodyPart - 2; i > 0; i--) {
        Point frontBodyPartPoint = snakeBodyPart[i - 1].getLocation();
        snakeBodyPart[i].setLocation(frontBodyPartPoint);
    }
    snakeBodyPart[0].setBounds(headLocX, headLocY, SNAKE_BODY_PART_SQURE, SNAKE_BODY_PART_SQURE);
}

public void snakeKeyPressed(KeyEvent e) {
    // snake should move to left when player pressed left arrow
    if (isRunningLeft == true && e.getKeyCode() == 37) {
        directionX = -SNAKE_BODY_PART_SQURE; // means snake move right to left by 10 pixel
        directionY = 0;
        isRunningRight = false;     // means snake cant move from left to right
        isRunningUp = true;         // means snake can move from down to up
        isRunningDown = true;       // means snake can move from up to down
    }
    // snake should move to up when player pressed up arrow
    if (isRunningUp == true && e.getKeyCode() == 38) {
        directionX = 0;
        directionY = -SNAKE_BODY_PART_SQURE; // means snake move from down to up by 10 pixel
        isRunningDown = false;     // means snake can move from up to down
        isRunningRight = true;     // means snake can move from left to right
        isRunningLeft = true;      // means snake can move from right to left
    }
    // snake should move to right when player pressed right arrow
    if (isRunningRight == true && e.getKeyCode() == 39) {
        directionX = +SNAKE_BODY_PART_SQURE; // means snake move from left to right by 10 pixel
        directionY = 0;
        isRunningLeft = false;
        isRunningUp = true;
        isRunningDown = true;
    }
    // snake should move to down when player pressed down arrow
    if (isRunningDown == true && e.getKeyCode() == 40) {
        directionX = 0;
        directionY = +SNAKE_BODY_PART_SQURE; // means snake move from left to right by 10 pixel
        isRunningUp = false;
        isRunningRight = true;
        isRunningLeft = true;
    }
}

private void createThread() {
    // start thread
    Thread thread = new Thread(new Runnable() {

        public void run() {
            runIt();
        }
    });
    thread.start(); // go to runIt() method
}

public void runIt() {
    while (true) {
        if(isRunning) {
            // Process what should be next step of the snake.
            processNextStep();
            try {
                Thread.sleep(selectedSpeed);
            } catch (InterruptedException ie) {
                ie.printStackTrace();
            }
        }
    }
}
}

主类:

public class Main {
/**
 * @param args the command line arguments
 */
public static void main(String[] args) {
    new Snake();
}
}

我的问题是，当我运行游戏时，指示不起作用。蛇只是自动地朝一个方向移动，没有其他任何 Action 。

你觉得怎么样？

Answer 1

不要使用KeyListener，尤其是在像JFrame这样的顶级容器上。

KeyListener 仅当其注册的组件可聚焦且具有焦点时才会引发按键事件。 JFrame 有一个 JRootPane、内容和可能的玻璃 Pane ，它们都会妨碍框架每次接收键盘焦点(这是在您添加任何其他组件之前)它)。

相反，请使用 key bindings API这将允许您定义将引发关键事件的焦点级别

不要使用null布局。像素完美布局是现代 UI 设计中的一种幻觉，您无法控制字体、DPI、渲染管道或其他会改变组件在屏幕上渲染方式的因素。

Swing 旨在与布局管理器配合来克服这些问题。如果您坚持忽略这些功能并违背 API 设计，请做好迎接许多头痛和永无休止的艰苦工作的准备......