错误: 无法初始化主类 SimpleGUI 原因: java.lang.NoClassDefFoundError: myDrawPanel (wrong nam

Foools 2021-02-23 11:53:29

错误: 无法初始化主类 SimpleGUI
原因: java.lang.NoClassDefFoundError: myDrawPanel (wrong name: MyDrawPanel)

代码目的：显示一个面板，带有一个随机颜色的圆和一个按钮，点击按钮，圆变颜色。
请问如何修改代码？

import javax.swing.*;

import java.awt.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;



class MyDrawPanel extends JPanel {

    public void paintComponent(Graphics g) {

        Graphics2D graphics2D = (Graphics2D) g;

        int red = (int) (Math.random()*255);

        int green = (int) (Math.random()*255);

        int blue = (int) (Math.random()*255);

        Color startColor = new Color(red,green,blue);



        red = (int) (Math.random()*255);

        green = (int) (Math.random()*255);

        blue = (int) (Math.random()*255);

        Color endColor = new Color(red,green,blue);



        GradientPaint gradientPaint = new GradientPaint(70,70,startColor,150,150,endColor);

        graphics2D.setPaint(gradientPaint);     //将虚拟的笔刷画成渐层

        graphics2D.fillOval(70,70,100,100);     //用目前的笔刷来填满椭圆形区域

    }

}



public class SimpleGUI implements ActionListener {



    JFrame frame;



    public static void main(String[] args){

        SimpleGUI gui = new SimpleGUI();

        gui.go();

    }



    public void actionPerformed(ActionEvent event){

        frame.repaint();

    }



    public void go(){

        frame = new JFrame();

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);       //设置关闭即停止



        JButton button = new JButton("do not click") ;

        button.addActionListener(this);

        MyDrawPanel drawPanel = new MyDrawPanel();    //创建我们的myPanel对象



        frame.add(BorderLayout.CENTER,drawPanel);     //add进frame框架中

        frame.add(BorderLayout.SOUTH,button);



        frame.setSize(300,300);

        frame.setVisible(true);     //设置框架为可见

    }



}