java - 如何在java弹出菜单中显示鼠标XY坐标？

Question

我无法在鼠标指针下的 JPopupMenu 上显示鼠标的 x、y 坐标。我在代码中使用 JlayerPane 的原因是能够将笛卡尔坐标系动态添加到 JPopupMenu，就像您在 CAD 应用程序中看到的那样。

有谁知道为什么它在正确绘制时不显示？

public void show popupwindow(JPanel parentPanel, int xLocation, int yLocation){
    Box selectionBox = createSelectionBox();

    JPopupMenu popupMenu = new JPopupMenu();

    // create an instance of my custom mouse cursor label
    XYMouseLabel mouseLabel = new XYMouseLabel();
    mouseLabel.setBounds(0, 0, selectionBox.getWidth(), selectionBox.getHeight());

    JPanel panel = new JPanel();
    panel.setSize(new Dimension(500, 400));

    JLayeredPane layeredPane = new JLayeredPane();
    layeredPane.setPreferredSize(new Dimension(400, 300));
    layeredPane.setBorder(BorderFactory.createTitledBorder("Move the Mouse to get coordinate"));

    layeredPane.addMouseMotionListener(new MouseMotionAdapter() {
        @Override
        public void mouseMoved(MouseEvent me) {
            super.mouseMoved(me);
            mouseLabel.x = me.getX();
            mouseLabel.y = me.getY();
            mouseLabel.repaint();
        }
    });

    layeredPane.add(mouseLabel , JLayeredPane.DRAG_LAYER);
    layeredPane.add(selectionBox, 2, 0);

    panel.add(layeredPane);
    popupMenu.add(panel);
    popupMenu.show(parentPanel , xLocation,yLocation)
 }

    public class XYMouseLabel extends JComponent {
        public int x;
        public int y;

        public XYMouseLabel() {
            this.setBackground(Color.green);
        }

        protected void paintComponent(Graphics g)
        {
            super.paintComponent(g);
            Graphics2D g2 = (Graphics2D) g;
            g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            //hier paint the cartesian coordinate system
            String s = x + ", " + y;
            g2.setColor(Color.red);
            g2.drawString(s, x, y);
        }
    }