Java之GUI 簡易貪吃蛇

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public class Data {

    public static URL headerURL = Data.class.getResource("statics/header.png");
    public static ImageIcon header = new ImageIcon(headerURL);
    public static URL upURL = Data.class.getResource("statics/up.png");
    public static ImageIcon up = new ImageIcon(upURL);
    public static URL downURL = Data.class.getResource("statics/down.png");
    public static ImageIcon down = new ImageIcon(downURL);
    public static URL leftURL = Data.class.getResource("statics/left.png");
    public static ImageIcon left = new ImageIcon(leftURL);
    public static URL rightURL = Data.class.getResource("statics/right.png");
    public static ImageIcon right = new ImageIcon(rightURL);
    public static URL bodyURL = Data.class.getResource("statics/body.png");
    public static ImageIcon body = new ImageIcon(bodyURL);
    public static URL foodURL = Data.class.getResource("statics/food.png");
    public static ImageIcon food = new ImageIcon(foodURL);
}

public class GamePanel extends JPanel implements KeyListener, ActionListener {

    int length;
    int[] snakeX = new int[600]; //蛇x座標
    int[] snakeY = new int[500];

    boolean isStart = false;

    String fx;

    Timer timer = new Timer(100, this); //100浩毫秒執行一次

    int foodX; //食物座標
    int foodY;
    Random random = new Random();

    boolean isFail = false;

    int score;

    public GamePanel() {
        init();
        //獲得焦點和鍵盤事件
        this.setFocusable(true);
        this.addKeyListener(this);
        timer.start();
    }

    public void init() {
        length = 3;
        snakeX[0] = 100;
        snakeY[0] = 100;
        snakeX[1] = 75;
        snakeY[1] = 100;
        snakeX[2] = 50;
        snakeY[2] = 100;
        fx = "R";

        foodX = 25 + 25 * random.nextInt(34);
        foodY = 75 + 25 * random.nextInt(24);
        score = 0;
    }

    //繪製面板 遊戲裏的所有東西 都用這個畫筆畫
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g); //清屏

        //繪製靜態面板
        this.setBackground(Color.WHITE);
        Data.header.paintIcon(this, g, 25, 11);
        g.fillRect(25, 75, 850, 600);

        g.setColor(Color.WHITE);
        g.setFont(new Font("微軟雅黑", Font.BOLD, 18));
        g.drawString("長度: " + length, 750, 35);
        g.drawString("分數: " + score, 750, 50);

        Data.food.paintIcon(this, g, foodX, foodY);

        if (fx.equals("R")) {
            Data.right.paintIcon(this, g, snakeX[0], snakeY[0]);
        } else if (fx.equals("L")) {
            Data.left.paintIcon(this, g, snakeX[0], snakeY[0]);
        } else if (fx.equals("U")) {
            Data.up.paintIcon(this, g, snakeX[0], snakeY[0]);
        } else if (fx.equals("D")) {
            Data.down.paintIcon(this, g, snakeX[0], snakeY[0]);
        }

        for (int i = 1; i < length; i++) {
            Data.body.paintIcon(this, g, snakeX[i], snakeY[i]);
        }


        if (!isStart) {
            g.setColor(Color.WHITE);
            g.setFont(new Font("微軟雅黑", Font.BOLD, 40));
            g.drawString("按下空格開始遊戲", 300, 300);
        }

        if (isFail) {
            g.setColor(Color.RED);
            g.setFont(new Font("微軟雅黑", Font.BOLD, 40));
            g.drawString("失敗，按下空格重新開始", 300, 300);
        }

    }

    @Override
    public void keyTyped(KeyEvent e) {

    }

    @Override
    public void keyPressed(KeyEvent e) {
        int keyCode = e.getKeyCode();
        if (keyCode == KeyEvent.VK_SPACE) {
            if (isFail) {
                isFail = false;
                init();
            } else {
                isStart = !isStart;
                repaint();
            }
            repaint();
        }
        if (keyCode == KeyEvent.VK_UP) {
            fx = "U";
        } else if (keyCode == KeyEvent.VK_DOWN) {
            fx = "D";
        } else if (keyCode == KeyEvent.VK_LEFT) {
            fx = "L";
        } else if (keyCode == KeyEvent.VK_RIGHT) {
            fx = "R";
        } else if (keyCode == KeyEvent.VK_ESCAPE) {
            System.exit(0);
        }
    }

    @Override
    public void keyReleased(KeyEvent e) {
    }

    //事件監聽--需要通過固定時間來刷新 1s 10次
    @Override
    public void actionPerformed(ActionEvent e) {
        if (isStart && !isFail) {

            //吃食物
            if (snakeX[0] == foodX && snakeY[0] == foodY) {
                length++;
                score += 10;
                foodX = 25 + 25 * random.nextInt(34);
                foodY = 75 + 25 * random.nextInt(24);
            }


            for (int i = length - 1; i > 0; i--) {
                snakeX[i] = snakeX[i - 1];
                snakeY[i] = snakeY[i - 1];
            }
            if (fx.equals("R")) {
                snakeX[0] = snakeX[0] + 25;
                if (snakeX[0] > 850) {
                    snakeX[0] = 25;
                }
            } else if (fx.equals("L")) {
                snakeX[0] = snakeX[0] - 25;
                if (snakeX[0] < 25) {
                    snakeX[0] = 850;
                }
            } else if (fx.equals("U")) {
                snakeY[0] = snakeY[0] - 25;
                if (snakeY[0] < 75) {
                    snakeY[0] = 650;
                }
            } else if (fx.equals("D")) {
                snakeY[0] = snakeY[0] + 25;
                if (snakeY[0] > 650) {
                    snakeY[0] = 75;
                }
            }
            //失敗判定 撞到自己失敗
            for (int i = 1; i < length; i++) {
                if (snakeX[0] == snakeX[i] && snakeY[0] == snakeY[i]) {
                    isFail = true;
                }
            }

            repaint();
        }
        timer.start();
    }
}

public class StartGame {
    public static void main(String[] args) {
        JFrame jFrame = new JFrame();

        jFrame.setBounds(10, 10, 900, 720);
        jFrame.setResizable(false);
        jFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        //遊戲界面都應該在遊戲面板上
        GamePanel gamePanel = new GamePanel();
        jFrame.add(gamePanel);

        jFrame.setVisible(true);
    }
}