Java编程练习题（七）
1. 设计一程序，创建一个用户界面，设计一块显示图片的空间及“开始”与“停止”两个按钮，当你按下“开始”按钮时连续显示10次图片，同时有一个进度条显示进度，显示的速度可以通过滑杆调节。
import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.event.*;
?
?public class MyProgressMonitor implements ActionListener,ChangeListener {
?
??? JFrame f = null;? //创建全局的类对象和变量，先赋空值，以备在各个方法中使用；
??? Timer timer = null;//计时器
??? ImageIcon[] icons = null;
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??? JSlider slider = null;//滑动杆
??? JLabel label = null;
??? int index=0;//图片数组的索引
??? int total=0;//图片的总数
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??? ProgressMonitor? pMonitor;
?
??? public MyProgressMonitor() {?? //写该类的构造方法：
??????? f = new JFrame("进度条例题");
??????? Container contentPane = f.getContentPane();
?
??????? icons = new ImageIcon[10];
??????? for (int i=0 ; i<10 ; i++)
??????????? icons[i] = new ImageIcon((i+1)+".gif");
??????? label = new JLabel(icons[0]);
??????? //实例化滑动杆对象：为水平放置，最小值0，最大值100，初始设置为50；
??????? slider = new JSlider(JSlider.HORIZONTAL,0, 100,50);
??????? slider.setPaintTicks(true);? //进度条刻度显示方式为True，下面的两个语句才起作用
??????? slider.setMajorTickSpacing(20);
??????? slider.setMinorTickSpacing(5);
??????? slider.setPaintLabels(true);
??????? slider.addChangeListener(this);
??????? JPanel panel = new JPanel();
??????? panel.setLayout(new GridLayout(1,2));
??????? JButton b1 = new JButton("Start");
??????? b1.addActionListener(new ButtonListener());
??????? panel.add(b1);
??????? JButton b2 = new JButton("Stop");
??????? b2.addActionListener(new ButtonListener());
??????? panel.add(b2);
??????? panel.setPreferredSize(new Dimension(200,30));
??????? timer = new Timer(slider.getValue()*10,this);
??????? contentPane.add(slider,BorderLayout.NORTH);
??????? contentPane.add(label,BorderLayout.CENTER);
? ??????contentPane.add(panel,BorderLayout.SOUTH);
??????? f.pack();
??????? f.setVisible(true);
??? }
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??? public static void main(String[] args){
?????? new MyProgressMonitor();
??? }
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??? public void actionPerformed(ActionEvent e){
??????? if (pMonitor.isCanceled()){
??????????? timer.stop();index = 0;total = 0;
??????? }
??????? else {
??????????? pMonitor.setProgress(total*10);
??????? }
??????? if (total < 10){
??????????? if (index == 5)
??????????? index = 0;
??????????? label.setIcon(icons[index]);
??????????? label.repaint();
??????????? index++;
??????????? total++;
??????? }
??????? else
?????????? timer.stop();
??? }
?
??? public void stateChanged(ChangeEvent e1){
???????? timer.setDelay(slider.getValue()*10);
??? }
?
??? class ButtonListener implements ActionListener{
??????? public void actionPerformed(ActionEvent e){
??????????? if (e.getActionCommand().equals("Start")){
??????????????? pMonitor = new ProgressMonitor(f,"Showing Progress Monitor","",0,100);
??????????????? pMonitor.setNote("Changing Photo....");
??????????????? pMonitor.setMillisToDecideToPopup(0);
??????????????? pMonitor.setMillisToPopup(1000);
??????????????? pMonitor.setProgress(0);
??????????????? index = 0;total = 0;
??????????????? timer.start();
??????????? }
??????????? if (e.getActionCommand().equals("Stop")){
??????????????? timer.stop();
?????????? }
??????? }
??? }
}
?
?
2编写一个商品类别类：属性有：类别好id，类别名name。
? package myshop;
? /**
?? * 商品类别信息类
?? */
? public class Category {
??? /** 商品类别ID */
??? private int id;
?
?
???? /** 商品类别名称 */
???? private String name;
?
?
???? /** 空构造方法 */
???? public Category() {
???? }
?
?
???? /**
????? * 构造方法
????? * @param id int 商品类别ID
????? * @param name String 商品类别名称
????? */
???? public Category(int id, String name) {
?????? this.id = id;
?????? this.name = name;
???? }
?
?
???? public int getId() {
?????? return id;
???? }
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???? public String getName() {
?????? return name;
???? }
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???? public void setId(int id) {
?????? this.id = id;
???? }
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???? public void setName(String name) {
?????? this.name = name;
???? }
?? }
