java - 将移动对象添加到 JFrame

Question

我正在创建一个java游戏。游戏中有一个英雄和一个泡泡。当我按下箭头键时，英雄应该移动，并且气泡应该有连续的对角线移动。当我分别将英雄或气泡直接添加到 JFrame 中时，我得到了所需的行为，但是当我将它们都添加时，我只得到一个非常小的正方形!我尝试将它们添加到同一个 JPanel 中，然后将该 JPanel 添加到 JFrame 中，但它不起作用。也许我必须为 JPanel 定义某种类型的布局。

我做错了什么？

代码:

public class Pang {
public static void main(String[] args) {

    JFrame f=new JFrame();
    JPanel gamePanel=new JPanel();
    gamePanel.setPreferredSize(new Dimension(800, 600));


    DrawHero d=new DrawHero();
    DrawBubble bubble=new DrawBubble();

    gamePanel.add(d);
    gamePanel.add(bubble);

    f.add(gamePanel);

    f.setVisible(true);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setSize(800, 600);
}
}


public class DrawHero extends JPanel implements ActionListener, KeyListener {
    Timer myTimer = new Timer(5, this);
    int x = 0, y = 0, dx = 0, dy = 0, step = 10;
    private transient Image imageHero = null;

    public DrawHero() {
        myTimer.start();
        addKeyListener(this);
        setFocusable(true);
        setFocusTraversalKeysEnabled(false);

    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;

        imageHero = getHeroImage();

        g2.drawImage(imageHero, x, y, 40, 40, null);

    }

    public Image getHeroImage() {
        Image image = null;

        image = getImage("hero.png");
        return image;
    }

    public Image getImage(String path) {
        Image tempImage = null;
        try {
            URL heroiURL = DrawHero.class.getResource(path);
            tempImage = Toolkit.getDefaultToolkit().getImage(heroiURL);
        } catch (Exception e) {
            System.out.println("Error loading hero image! - "
                    + e.getMessage());
        }
        return tempImage;
    }

    public void actionPerformed(ActionEvent e) {

        repaint();
    }

    public void moveUp() {

        y = y - step;

    }

    public void moveDown() {
        y = y + step;

    }

    public void moveLeft() {

        x = x - step;

    }

    public void moveRight() {
        x = x + step;

    }

    public void keyPressed(KeyEvent e) {
        int keyCode = e.getKeyCode();
        if (keyCode == KeyEvent.VK_UP) {
            moveUp();
        }
        if (keyCode == KeyEvent.VK_DOWN) {
            moveDown();
        }
        if (keyCode == KeyEvent.VK_LEFT) {
            moveLeft();
        }
        if (keyCode == KeyEvent.VK_RIGHT) {
            moveRight();
        }
    }

    public void keyTyped(KeyEvent e) {
    }

    public void keyReleased(KeyEvent e) {
    }
}


public class DrawBubble extends JPanel implements ActionListener, KeyListener {
    Timer myTimer = new Timer(5, this);
    int x = 100, y = 200, dx = 0, dy = 0, step = 10;
    private transient Image imageHero = null;

    public DrawBubble() {
        myTimer.start();
        addKeyListener(this);
        setFocusable(true);
        setFocusTraversalKeysEnabled(false);

    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;
        g2.fill(new Ellipse2D.Double(x, y, 40, 40));


    }


    public void actionPerformed(ActionEvent e) {

         x=x+dx;
         y=y+dy;
        repaint();
    }

    public void moveBubble() {
         dy=2;
         dx=2;
    }



    public void keyPressed(KeyEvent e) {
        moveBubble();

    }

    public void keyTyped(KeyEvent e) {
    }

    public void keyReleased(KeyEvent e) {
    }
}

Answer 1

我建议 DrawHero 和 DrawBubble(应分别称为 Hero 和 Bubble)都不应该扩展任何JComponent。相反，每个人都应该简单地知道如何在请求时将自己绘制到传递给它的 Graphics 对象。

然后，单个 GameField 或 PlayingArea 类应保留对所有 Bubble 对象和 Hero 的引用，并且draw 调用这些对象的 draw(Graphics) 方法。

使用这种方法，无需担心 GameField 组件内的布局(它们变得无关紧要)。

这是我在this answer中渲染静止物体所追求的基本策略。至 [ Collision detection with complex shapes .