java - Swing:同时移动两个图形

Question

我正在为我的中期项目开发空气曲棍球游戏。

我在处理两个图形时遇到问题，在本例中，有两个句柄，每个句柄由 3 个圆圈组成。由于 keyPressed 方法，我只能移动一个 handle 。

另一个问题是我无法限制移动域，例如当您按下→时，红色 handle 可能会超出框架宽度。

我知道第一个问题与线程有关，但我从上周开始研究这个主题。

我的问题在这门课上:

public class StartGamePanel extends JPanel implements KeyListener, ActionListener {

    double xCircle1 = 200;
    double yCircle1 = 100;

    double xCircle2 = 200;
    double yCircle2 = 700;

    double velX = 0, velY = 0;

    public StartGamePanel() {
        Timer t = new Timer(5, this);
        t.start();
        addKeyListener(this);
        setFocusable(true);
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;
        g.setColor(new Color(51, 153, 255));
        g.fillRoundRect(5, 5, 485, 790, 10, 10);

        addKeyListener(this);

        Graphics2D southArc = (Graphics2D) g;
        southArc.setColor(Color.WHITE);
        southArc.setStroke(new BasicStroke(3));
        southArc.drawArc(98, 640, 300, 300, 0, 180);

        //

        Graphics2D northArc = (Graphics2D) g;
        northArc.setColor(Color.WHITE);
        northArc.setStroke(new BasicStroke(3));
        northArc.drawArc(98, -143, 300, 300, 180, 180);

        Graphics2D line = (Graphics2D) g;
        line.setStroke(new BasicStroke(3));
        line.setColor(Color.white);
        line.drawLine(6, 395, 488, 395);

        Graphics2D dot = (Graphics2D) g;
        dot.setColor(Color.black);

        for (int j = 10; j < 800; j += 20) {
            for (int i = 6; i < 502; i += 20) {
                dot.drawLine(i, j, i, j);
            }
        }

        Graphics2D circle1 = (Graphics2D) g;
        circle1.setColor(new Color(255, 51, 51));
        Shape theCircle = new Ellipse2D.Double(xCircle1 - 40, yCircle1 - 40, 2.0 * 40, 2.0 * 40);
        circle1.fill(theCircle);

        Graphics2D circle2 = (Graphics2D) g;
        circle2.setColor(new Color(255, 102, 102));
        Shape theCircle2 = new Ellipse2D.Double(xCircle1 - 35, yCircle1 - 35, 2.0 * 35, 2.0 * 35);
        circle2.fill(theCircle2);

        Graphics2D circle3 = (Graphics2D) g;
        circle3.setColor(new Color(255, 51, 51));
        Shape theCircle3 = new Ellipse2D.Double(xCircle1 - 20, yCircle1 - 20, 2.0 * 20, 2.0 * 20);
        circle3.fill(theCircle3);

        Graphics2D circleprim = (Graphics2D) g;
        circleprim.setColor(new Color(0, 51, 102));
        Shape theCircleprim = new Ellipse2D.Double(xCircle2 - 40, yCircle2 - 40, 2.0 * 40, 2.0 * 40);
        circleprim.fill(theCircleprim);

        Graphics2D circle2prim = (Graphics2D) g;
        circle2prim.setColor(new Color(0, 102, 204));
        Shape theCircle2prim = new Ellipse2D.Double(xCircle2 - 35, yCircle2 - 35, 2.0 * 35, 2.0 * 35);
        circle2prim.fill(theCircle2prim);

        Graphics2D circle3prim = (Graphics2D) g;
        circle3prim.setColor(new Color(0, 51, 102));
        Shape theCircle3prim = new Ellipse2D.Double(xCircle2 - 20, yCircle2 - 20, 2.0 * 20, 2.0 * 20);
        circle3prim.fill(theCircle3prim);

        Graphics2D ball = (Graphics2D) g;
        ball.setColor(new Color(224, 224, 224));
        Shape theball = new Ellipse2D.Double(200 - 20, 400 - 20, 2.0 * 20, 2.0 * 20);
        ball.fill(theball);

        Graphics2D ball2 = (Graphics2D) g;
        ball2.setColor(new Color(160, 160, 160));
        Shape theball2 = new Ellipse2D.Double(200 - 15, 400 - 15, 2.0 * 15, 2.0 * 15);
        ball2.fill(theball2);

        Graphics2D goal = (Graphics2D) g;
        goal.setColor(Color.BLACK);
        goal.fill3DRect(100, 0, 300, 10, true);

        Graphics2D goal2 = (Graphics2D) g;
        goal2.setColor(Color.BLACK);
        goal2.fill3DRect(100, 790, 300, 10, true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        repaint();
        xCircle1 += velX;
        yCircle1 += velY;
    }

    @Override
    public void keyPressed(KeyEvent e) {
        int code = e.getKeyCode();
        if (code == KeyEvent.VK_UP) {
            velY = -2;
            velX = 0;
        }
        if (code == KeyEvent.VK_DOWN) {
            velY = 2;
            velX = 0;
        }
        if (code == KeyEvent.VK_LEFT) {
            if (xCircle1 < 0) {
                velY = 0;
                velX = 0;
            } else {
                velY = 0;
                velX = -2;
            }
        }
        if (code == KeyEvent.VK_RIGHT) {
            if (xCircle1 > 200) {
                velY = 0;
                velX = 0;
            }
            velY = 0;
            velX = 2;
        }
    }

    @Override
    public void keyReleased(KeyEvent e) {
        int code = e.getKeyCode();
        if (code == KeyEvent.VK_UP) {
            velY = 0;
            velX = 0;
        }
        if (code == KeyEvent.VK_DOWN) {
            velY = 0;
            velX = 0;
        }
        if (code == KeyEvent.VK_LEFT) {
            velY = 0;
            velX = 0;
        }
        if (code == KeyEvent.VK_RIGHT) {
            velY = 0;
            velX = 0;
        }
    }

    @Override
    public void keyTyped(KeyEvent e) { }
}

谢谢!

Answer 1

您的关键监听器应该尽可能快，这样它就不会阻止后续的关键事件。由于几个人几乎同时按键，这种情况在游戏中很常见。

因此建议使用单独的线程来监听按键，这将快速将事件添加到队列中。然后，该队列将在 EDT(Swing 主线程)上进行处理并绘制结果。