如何在java弹出菜单中显示鼠标XY坐标？

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

有人知道它在正确绘制时为什么不显示吗？

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);
        }
    }

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不确定，但IIRC

final

和

String

彼此有副作用。字符串是不可变的，因此如果您最终生成一个JLabel，我认为您需要在其上创建一个

XYMouseLabel

的实例并将其分配给

mouseLabel

，但这永远不会添加到任何内容中。您将

alsXYMouseLabel

添加到

layeredPane

中，但我不知道这是什么，很抱歉，我纠正的是一个打字错误。它应该是一个鼠标贴。请确保将您的代码复制粘贴到新项目中，并确保在将其发布到此处之前它已编译并运行。