java - 鼠标坐标不断叠加-Java

Question

我试图让鼠标坐标显示在面板中，但每次我移动光标时，消息和新坐标都会显示在前一个上。我正在将 MouseMotionListener 与 JPanel 一起使用。我无法找出问题所在。

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.event.MouseMotionListener;
public class Main extends JPanel implements MouseMotionListener {
public JLabel label;
    public static void main(String[] args) {
      new Main();
      JFrame frame = new JFrame();
      frame.setTitle("MouseCoordinates");
      frame.setSize(400, 400);
      frame.addWindowListener(new WindowAdapter() {
        public void windowClosing(WindowEvent we) {
        System.exit(0);
            }
        });
        Container contentPane = frame.getContentPane();
        contentPane.add(new Main());
        frame.setVisible(true);
    }
      public Main() {
      setSize(400, 400);
      label = new JLabel("No Mouse Event Captured", JLabel.CENTER);
      add(label);
      addMouseMotionListener(this);
    }
    public void mouseMoved(MouseEvent e) {
    label.setText("Mouse Cursor Coordinates => X:" + e.getX() + " |Y:" + e.getY());
    }
    public void mouseDragged(MouseEvent e) {}
    }

Answer 1

您正在创建 Main 两次。

public class Main extends JPanel implements MouseMotionListener {
public JLabel label;

public static void main(String[] args) {
    Main m = new Main();// create an object and reference it
    JFrame frame = new JFrame();
    frame.setTitle("MouseCoordinates");
    frame.setSize(400, 400);
    frame.addWindowListener(new WindowAdapter() {
        public void windowClosing(WindowEvent we) {
            System.exit(0);
        }
    });
    Container contentPane = frame.getContentPane();
    contentPane.add(m);
    frame.setVisible(true);
}
//...

您的问题是创建了两次 Main 对象(这是一个 jpanel)，然后出现了两次书写。如果您给 Main 对象一个引用，那么您的问题应该得到解决。