Java 中的按钮单击事件

package delftstack;

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

class ActionEventDemo implements ActionListener {
    JFrame Demo_Frame=new JFrame();
    JButton Demo_Button=new JButton("Click Here");

    ActionEventDemo(){
    	Prepare_GUI();
    	Button_Properties();
    }

    public void Prepare_GUI(){
    	Demo_Frame.setTitle("Demo Window");
    	Demo_Frame.getContentPane().setLayout(null);
    	Demo_Frame.setVisible(true);
    	Demo_Frame.setBounds(400,100,400,400);
    	Demo_Frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    public void Button_Properties(){
        Demo_Button.setBounds(150,200,150,80);
        Demo_Frame.add(Demo_Button);
        Demo_Button.addActionListener(this);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        //Changing Background Color
        Demo_Frame.getContentPane().setBackground(Color.red);

    }
}

public class On_Click {
    public static void main(String[] args)
    {
        new ActionEventDemo();
    }
}