在一个frame设置四个组件

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;

class TouChaCol{
    JFrame frame;
    JLabel label;
    
    public static void main(String [] args){
        TouChaCol ch = new TouChaCol();
        ch.go();
    }
    
    class LabelActionListener implements ActionListener{
        public void actionPerformed(ActionEvent e){
            label.setText("fuck you click me");
        }
    }
    
    class ColorActionListener implements ActionListener{
        public void actionPerformed(ActionEvent e){
            frame.repaint();
        }
    }
    
    public void go(){
        frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        Panel panel = new Panel();
        
        label = new JLabel("yoooyo helllo who are you");
        JButton button1 = new JButton("change the color");
        button1.addActionListener(new ColorActionListener());
        
        JButton button2 = new JButton("change the label");
        button2.addActionListener(new LabelActionListener());
        
        frame.getContentPane().add(BorderLayout.SOUTH,button1);
        frame.getContentPane().add(BorderLayout.EAST,button2);
        frame.getContentPane().add(BorderLayout.WEST,label);
        frame.getContentPane().add(BorderLayout.CENTER,panel);
        
        frame.setSize(700, 700);
        frame.setVisible(true);
    }
}

import javax.swing.*;
import java.awt.*;
public class Panel extends JPanel{
    public void paintComponent(Graphics g){
        g.fillRect(0, 0, this.getWidth(), this.getHeight());
        int red = (int)(Math.random() * 255);
        int green = (int)(Math.random() * 255);
        int blue = (int)(Math.random() * 255);
        Color myColor = new Color(red,green,blue);
        g.setColor(myColor);
        g.fillOval(70,70, 100, 100);
    }
}

在Panel（继承自JPanel）类中方法paintComponent（）

fillRect（0,0,this.width,this.height）表示在该panel的(x,y)坐标为起始，this.width和this.height也表示该面板的宽高

需要作出改变的组件，放做全局

在go中有代码：

button1.addActionListener(new ColorActionListener());

button2.addActionListener(new LabelActionListener());

在外部类对象中新建的内部类对象会与该外部类对象产生联结，内部类对象可直接调用外部类对象的实例变量，也因此，需要改变的组件做实例变量也是为了给内部对象使用

 BoarderLayout.CENTER 这个中间是相对于其他组件而言的，当其左边的组件变小时，他可能会变大