在JAVA中实现图形界面退出(已测试)

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class TestGUI 
{
    public static void main(String[] args) 
    {
        frame f = new frame();
        //还可以在这里加上一句
        ①f.setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
        f.setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
        f.setVisible(true);
        f.addWindowListener(new WindowAdapter()
        {
            public void windowClosing(WindowEvent e)
            {
                int i;
                i=JOptionPane.showConfirmDialog(null,"are you ok");
                
                if(i==JOptionPane.YES_OPTION)
                {
                    System.exit(0););//或者还可以写成
                    this.dispose();//这两句都可以实现关闭窗口
                }
                else
                {
                    
                    
                }
 
            }
        });
    }
}
 
class panel extends JPanel
{
    public panel()
    {
        makeButton("red",Color.RED);
        makeButton("yellow",Color.yellow);
    }
 
    private void makeButton(String name,final Color c)
    {
        Button button=new Button(name);
        button.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent event)
            {
                setBackground(c);
            }
        }    
        );
        add(button);
 
    }
 
}
 
class frame extends JFrame
{
    public frame()
    {
        setTitle("test");
        setSize(300,200);
        panel p= new panel();
        
        add(p);
    }
 
}
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