java程序设计教程(第六版)课后习题答案(17)

frame.setVisible(true);

}

}

///////////////////////////////////////////////////////////////////// App4.14源程序：

//AddPanel.java

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class AddPanel extends JPanel {

/**

*

*/

private static final long serialVersionUID = 8617749572451960356L; private int count;

private JButton push,push1;

private JLabel label;

int num=50;

public AddPanel()

{

push=new JButton("Add!");

push1=new JButton("Minus!");

push.addActionListener(new ButtonListener());

push1.addActionListener(new ButtonListener());

label=new JLabel("Number:"+num);

add (push);

add (push1);

add (label);

setPreferredSize(new Dimension(400,100));

setBackground(Color.pink);

}

private class ButtonListener implements ActionListener {

public void actionPerformed(ActionEvent event)

{