可以将侦听器和绘图面板设置为单独的类。为此，我将主类的一个实例传递给侦听器类和绘图类 import java.awt.Color; import java.awt.Graphics; import java.awt.Point; import java.a

可以将侦听器和绘图面板设置为单独的类。为此，我将主类的一个实例传递给侦听器类和绘图类

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.event.MouseInputAdapter;

public class DrawingTest implements Runnable {

    private JFrame frame;

    private MyDrawPanel drawPanel;

    private List<Point> points;

    public DrawingTest() {
        points = new ArrayList<Point>();
    }

    @Override
    public void run() {
        frame = new JFrame("Bouncing Vertices");

        drawPanel = new MyDrawPanel(this);
        MyListener alpha = new MyListener(this);
        drawPanel.addMouseMotionListener(alpha);
        drawPanel.addMouseListener(alpha);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(drawPanel);
        frame.setSize(800, 600);
        frame.setVisible(true);
    }

    public JPanel getDrawingPanel() {
        return drawPanel;
    }

    public List<Point> getPoints() {
        return points;
    }

    public void setPoint(int x, int y) {
        points.add(new Point(x, y));
    }

    public void resetPoints() {
        points.clear();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new DrawingTest());
    }

    private class MyListener extends MouseInputAdapter {

        private DrawingTest drawingTest;

        public MyListener(DrawingTest drawingTest) {
            this.drawingTest = drawingTest;
        }

        @Override
        public void mouseDragged(MouseEvent event) {
           drawingTest.setPoint(event.getX(), event.getY());
           drawingTest.getDrawingPanel().repaint();
        }

        @Override
        public void mouseReleased(MouseEvent event) {
            drawingTest.resetPoints();
        }

    }

}

class MyDrawPanel extends JPanel {

    private DrawingTest drawingTest;

    public MyDrawPanel(DrawingTest drawingTest) {
        this.drawingTest = drawingTest;
    }

    @Override
    public void paintComponent(Graphics g) {
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, this.getWidth(), this.getHeight());
        g.setColor(Color.BLUE);
        for (int i = 1; i < drawingTest.getPoints().size(); i++) {
            Point p1 = drawingTest.getPoints().get(i - 1);
            Point p2 = drawingTest.getPoints().get(i);
            g.drawLine(p1.x, p1.y, p2.x, p2.y);
        }
    }
}

导入java.awt.Color；
导入java.awt.Graphics；
导入java.awt.Point；
导入java.awt.event.MouseEvent；
导入java.util.ArrayList；
导入java.util.List；
导入javax.swing.JFrame；
导入javax.swing.JPanel；
导入javax.swing.SwingUtilities；
导入javax.swing.event.MouseInputAdapter；
公共类DrawingTest实现可运行{
私有JFrame；
私人MyDrawPanel drawPanel；
私人名单点；
公共绘图测试（）{
points=新的ArrayList（）；
}
@凌驾
公开募捐{
frame=新JFrame（“反弹顶点”）；
drawPanel=新的MyDrawPanel（此）；
MyListener alpha=新的MyListener（此）；
drawPanel.addMouseMotionListener（alpha）；
drawPanel.addMouseListener（α）；
frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）；
frame.getContentPane（）.add（drawPanel）；
框架设置尺寸（800600）；
frame.setVisible（true）；
}
公共JPanel getDrawingPanel（）{
返回面板；
}
公共列表getPoints（）{
返回点；
}
公共无效设定点（整数x，整数y）{
点。添加（新点（x，y））；
}
公共无效重置点（）{
点。清除（）；
}
公共静态void main（字符串[]args）{
SwingUtilities.invokeLater（newDrawingTest（））；
}
私有类MyListener扩展了MouseInputAdapter{
私人绘图测试绘图测试；
公共MyListener（DrawingTest DrawingTest）{
this.drawingTest=drawingTest；
}
@凌驾
公共无效鼠标标记（鼠标事件）{
drawingTest.setPoint（event.getX（），event.getY（））；
drawingTest.getDrawingPanel（）.repaint（）；
}
@凌驾
公共无效MouseEvent事件（MouseEvent事件）{
drawingTest.resetPoints（）；
}
}
}
类MyDrawPanel扩展了JPanel{
私人绘图测试绘图测试；
公共MyDrawPanel（DrawingTest DrawingTest）{
this.drawingTest=drawingTest；
}
@凌驾
公共组件（图形g）{
g、 setColor（Color.WHITE）；
g、 fillRect（0，0，this.getWidth（），this.getHeight（））；
g、 setColor（Color.BLUE）；
对于（int i=1；i

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.event.MouseInputAdapter;

public class DrawingTest implements Runnable {

    private JFrame frame;

    private MyDrawPanel drawPanel;

    private List<Point> points;

    public DrawingTest() {
        points = new ArrayList<Point>();
    }

    @Override
    public void run() {
        frame = new JFrame("Bouncing Vertices");

        drawPanel = new MyDrawPanel(this);
        MyListener alpha = new MyListener(this);
        drawPanel.addMouseMotionListener(alpha);
        drawPanel.addMouseListener(alpha);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(drawPanel);
        frame.setSize(800, 600);
        frame.setVisible(true);
    }

    public JPanel getDrawingPanel() {
        return drawPanel;
    }

    public List<Point> getPoints() {
        return points;
    }

    public void setPoint(int x, int y) {
        points.add(new Point(x, y));
    }

    public void resetPoints() {
        points.clear();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new DrawingTest());
    }

    private class MyListener extends MouseInputAdapter {

        private DrawingTest drawingTest;

        public MyListener(DrawingTest drawingTest) {
            this.drawingTest = drawingTest;
        }

        @Override
        public void mouseDragged(MouseEvent event) {
           drawingTest.setPoint(event.getX(), event.getY());
           drawingTest.getDrawingPanel().repaint();
        }

        @Override
        public void mouseReleased(MouseEvent event) {
            drawingTest.resetPoints();
        }

    }

}

class MyDrawPanel extends JPanel {

    private DrawingTest drawingTest;

    public MyDrawPanel(DrawingTest drawingTest) {
        this.drawingTest = drawingTest;
    }

    @Override
    public void paintComponent(Graphics g) {
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, this.getWidth(), this.getHeight());
        g.setColor(Color.BLUE);
        for (int i = 1; i < drawingTest.getPoints().size(); i++) {
            Point p1 = drawingTest.getPoints().get(i - 1);
            Point p2 = drawingTest.getPoints().get(i);
            g.drawLine(p1.x, p1.y, p2.x, p2.y);
        }
    }
}