Java 为什么我的JMenuBar没有激活？（单击时闪烁，但不会完全显示）

我正在构建一个JFrame，它在顶部实现一个JMenuBar。帧的其余部分是一个JComponent，其中包含一个通过双缓冲光栅图像在屏幕上移动的动画球。每当我单击菜单项时，它们都会闪烁，但不会完全显示。我的JComponent使用paintComponent绘图，它是否出于某种原因覆盖了我的菜单？我创建单独JComponent的全部原因是为了避免元素之间的冲突。下面是我的JFrame和JComponent的代码

我的JComponent使用paintComponent绘图，它是否出于某种原因覆盖了我的菜单

您没有使用paintComponent方法，这可能就是问题所在。您使用G而不是C创建了自己的方法，然后尝试使用图形，而不是通常传递到paintComponent方法中的图形

不要喜欢你的代码。只需将绘制代码放在paintComponent方法中，并使用其图形对象

在绘制代码中没有while循环，只需使用Swing计时器来安排动画

有关更多信息和示例，请阅读上Swing教程的部分

public class Driver
{
    public static void main(String[] args)
    {
        // Creates Game window.
        MyFrame myFrame = new MyFrame();
        DrawingSurface drawingSurface = new DrawingSurface();

        myFrame.add(drawingSurface);
        drawingSurface.setup();

        myFrame.makeMenu();

        drawingSurface.paintGomponent();

    }
}

class MyFrame extends JFrame
{
    /**
     * Default serial version of long defined to suppress serial warning.
     */
    private static final long serialVersionUID = 1L;

    public MyFrame()
    {
        setTitle("Breakout");
        setSize(800,600);
        setResizable(false);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setLocationRelativeTo(null); // Sets location to center of screen (stackoverflow.com)
        setVisible(true);
    }

    public void makeMenu()
    {
        JMenuBar menuBar = new JMenuBar();

        // Adds menu "Game" with sub-menu "New", "Pause" and "Exit".
        JMenu game = new JMenu("Game");
        JMenuItem newGame = new JMenuItem("New");
        newGame.setToolTipText("Starts a new game");
        JMenuItem pauseGame = new JMenuItem("Pause");
        pauseGame.setToolTipText("Pauses the game");
        JMenuItem exitGame = new JMenuItem("Exit");
        exitGame.setToolTipText("Exits the game");

        // Adds menu "High Score".
        JMenu highScores = new JMenu("High Scores");
        highScores.setToolTipText("Displays high scores");

        // Adds menus to menu bar and sets menu bar to frame.
        game.add(newGame);
        game.add(pauseGame);
        game.add(exitGame);
        menuBar.add(game);
        menuBar.add(highScores);
        setJMenuBar(menuBar);
    }
}

class DrawingSurface extends JComponent
{
    private int XResolution = 800;
    private int YResolution = 600;

    private Image raster;
    private Graphics rasterGraphics;


    public void paintGomponent()
    {
        super.paintComponent(rasterGraphics);

        // Player ball used in game.
        Ball ball = new Ball(400, 300, 2.0f, 1.0f);

        while(true)
        {
            // Time for use with sleep, to make game run more smoothly.
            long time = System.currentTimeMillis();

            drawBackground();

            ball.moveBall(ball);
            ball.drawBall(rasterGraphics);

            // Draws buffered raster graphics to frame.
            getGraphics().drawImage(raster, 0, 0, XResolution, YResolution, null);
            long changeInTime = System.currentTimeMillis() - time;
            try{Thread.sleep(10-changeInTime);}catch(Exception e){}
        }
    }

    private void drawBackground()
    {
        rasterGraphics.setColor(Color.black);
        rasterGraphics.fillRect(0, 0, XResolution, YResolution);
    }

    public void setup()
    {
        raster = createImage(XResolution, YResolution);
        rasterGraphics = raster.getGraphics();
    }
}