Slider,Timer,Progress的使用

滑动杆(Slider),时间控制(Timer),进度元件(Progress)的使用与介绍:
14-1:使用JSlider组件:
JSlider的类层次结构图:
  java.lang.Object
   --java.awt.COmponent
    --java.awt.Container
     --javax.swing.JComponent
      --javax.swing.JSlider
    我们曾在前面提到JScrollBar这个组件,可以让用户决定拉曳时一次滚动的区域大小,并且可以得到目前滚动杆上的值,看起来JScrollBar好象可以当作这
种微调的组件.然而JScrollBar通常置于窗口的最右边或最下面,且常JScrollBar来使用,因此在外观上或
实际应用上并不适合当微调工具使用,不过不用担心,java提供了一个特别为微调设计的组件,那就是JSlider.JSlider不仅可以置于
面版的任何地方,也可以在JSlider上标上刻度与数字,既美观又实用,我们现在就来看如何使用JSlider吧.

JSlider的构造函数:
JSlider():建立一个水平的JSlider对象,刻度从0-100,初始刻度为50.
JSlider(BoundedRangeModel brm):使用默认模式建立一个水平的JSlider对象.
JSlider(int orientation):建立一个自定义方向的JSlider对象,刻度从0-100,初始刻度为50.
JSlider(int min,int max):建立一个水平的JSlider对象,自定义刻度,从min-max,初始刻度为50.
JSlider(int min, int max,int value):建立一个水平的JSlider的对象,自定义刻度与初始值.
JSlider(int orientation,int min,int max,int value):建立一个自定义方向,刻度与刻度初始值的JSlider对象.
   要使用JSlider组件就不得不提到JSlider事件的处理.当用户在JSlider上滑动杆时,就会产生ChangeEvent事件,若我们要处理
ChangeEvent事件就必须实作ChangeListener界面,此界面定义了一个方法,那就是stateChanged().通常我们在这个方法上会取得或
置滑动杆的相关信息,例如滑动杆的延伸区(extent),最大最小值或滑动杆目前所在刻度等等.我们来看下一节所举的范例:

14-1-1:建立JSlider组件:
   这个范例我们建立了3个JSlider组件,并对每个JSlider组件做相关的设置,例如设置方向,初始值,最大最小值,延伸区值(extent)
等.

import javax.swing.*;//ChangeEvent事件是属于Swing事件,若要处理此事件必须将import swing的event package进来.
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.event.*;

public class SliderDemo1 implements ChangeListener
{
    JFrame f = null;
    JSlider slider1;
    JSlider slider2;
    JSlider slider3;
    JLabel label1;
    JLabel label2;
    JLabel label3;
   
    public SliderDemo1()                          
    {
        f = new JFrame("JSlider Example");
        Container contentPane = f.getContentPane();
       
        JPanel panel1 = new JPanel();
        panel1.setLayout(new GridLayout(2,1));
        slider1 = new JSlider();//建立一个默认的JSlider组件.
        label1 = new JLabel("目前刻度："+slider1.getValue());
        panel1.add(label1);
        panel1.add(slider1);
        panel1.setBorder(BorderFactory.createTitledBorder(
        BorderFactory.createEtchedBorder(),"Slider 1",TitledBorder.LEFT,
        TitledBorder.TOP));
       
        JPanel panel2 = new JPanel();
        panel2.setLayout(new GridLayout(2,1));
        /*下面五行程序建立一个水平方向的JSlider组件,并设置其取大值,最小值,初始值与延伸区值,所谓的延伸区值我们在前面
         *JScrollBar中也提到过,意思是限制JSlider刻度可变动的范围,也就是说延伸区就像是一个障碍区,是无法通行的.延伸区
         *设得越大,刻度可变动的范围就越小.例如若minimum值设为0,maximan值设为100,而extent值设为0,则JSlider刻度可变动
         *的区域大小为100-50-0=50刻度(从0-50).
         */
        slider2 = new JSlider(JSlider.HORIZONTAL);
        slider2.setMinimum(0);
        slider2.setMaximum(100);
        slider2.setValue(30);
        slider2.setExtent(50);
        label2 = new JLabel("目前刻度："+slider2.getValue());
        panel2.add(label2);
        panel2.add(slider2);
        panel2.setBorder(BorderFactory.createTitledBorder(
        BorderFactory.createEtchedBorder(),"Slider 2",TitledBorder.LEFT,
        TitledBorder.TOP));
       
        JPanel panel3 = new JPanel();
        panel3.setLayout(new GridLayout(2,1));
        //下面两行建立一个具有最大最小值的JSlider组件,并设置此JSlider组件为垂直方向.
        slider3 = new JSlider(20,80);
        slider3.setOrientation(JSlider.VERTICAL);
        label3 = new JLabel("目前刻度："+slider3.getValue());
        panel3.add(label3);
        panel3.add(slider3);
        panel3.setBorder(BorderFactory.createTitledBorder(
        BorderFactory.createEtchedBorder(),"Slider 3",TitledBorder.LEFT,
        TitledBorder.TOP));
       
        slider1.addChangeListener(this);
        slider2.addChangeListener(this);
        slider3.addChangeListener(this);
       
        panel1.setPreferredSize(new Dimension(300,100));
        panel2.setPreferredSize(new Dimension(300,100));
        panel3.setPreferredSize(new Dimension(150,200));
       
        GridBagConstraints c;
        int gridx,gridy,gridwidth,
            gridheight,anchor,fill,ipadx,ipady;
        double weightx,weighty;
        Insets inset;    
       
        GridBagLayout gridbag = new GridBagLayout();
        contentPane.setLayout(gridbag);
       
        gridx=0;               //第0行
                gridy=0;               //第0列
                gridwidth = 2;         //占两单位宽度
                gridheight = 1;        //占一单位高度
                weightx = 0;           //窗口增大时组件宽度增大比率0
                weighty = 0;           //窗口增大时组件高度增大比率0
                anchor = GridBagConstraints.CENTER; //容器大于组件size时将组件
              //置于容器中央
                fill = GridBagConstraints.BOTH;     //窗口拉大时会填满水平与垂
              //直空间
                inset = new Insets(0,0,0,0);        //组件间间距
                ipadx = 0;                          //组件内水平宽度
                ipady = 0;                          //组件内垂直高度
        c = new GridBagConstraints(gridx,gridy,gridwidth,gridheight,
            weightx,weighty,anchor,fill,inset,ipadx,ipady);
        gridbag.setConstraints(panel1,c);
        contentPane.add(panel1);
       
        gridx=0;
        gridy=1;
        c = new GridBagConstraints(gridx,gridy,gridwidth,gridheight,
            weightx,weighty,anchor,fill,inset,ipadx,ipady);
        gridbag.setConstraints(panel2,c);
        contentPane.add(panel2);
       
        gridx=2;
        gridy=0;
        gridwidth = 1;         //占一单位宽度
        gridheight = 2;        //占两单位高度
        c = new GridBagConstraints(gridx,gridy,gridwidth,gridheight,
            weightx,weighty,anchor,fill,inset,ipadx,ipady);
        gridbag.setConstraints(panel3,c);
        contentPane.add(panel3);
       
        f.pack();
        f.setVisible(true);
       
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }
   
    public static void main(String[] args)
    {
        new SliderDemo1();
    }
    //处理ChangeEvent事件,当用户移动滑动杆时,label上的值会随着用户的移动而改变.
    public void stateChanged(ChangeEvent e)
    {
        if ((JSlider)e.getSource() == slider1)
            label1.setText("目前刻度："+slider1.getValue());
        if ((JSlider)e.getSource() == slider2)
            label2.setText("目前刻度："+slider2.getValue());
        if ((JSlider)e.getSource() == slider3)
            label3.setText("目前刻度："+slider3.getValue());
    }
}

  注:由于slider3设置延伸区值(Extent)为50,因此slider2刻度可变动的区域只到50,因此当slider2超过50刻度时就算你再向右移
动,刻度值一样维持在50上.


14-1-2:为JSlider组件加入刻度.
    上面这个例子中,你是否觉得好像少了什么?没错,就是刻度!接下来,我们来设置JSlider的刻度与数字,并增加一些设置项目,完
整的JSlider组件就大功告成了.

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

public class SliderDemo2 implements ChangeListener
{
    JFrame f = null;
    JSlider slider1;
    JSlider slider2;
    JSlider slider3;
    JLabel label1;
    JLabel label2;
    JLabel label3;
   
    public SliderDemo2()                          
    {
        f = new JFrame("JSlider Example");
        Container contentPane = f.getContentPane();
       
        JPanel panel1 = new JPanel();
        panel1.setLayout(new GridLayout(2,1));
        slider1 = new JSlider();
        //setPaintTicks()方法是设置是否在JSlider加上刻度，若为true则下面两行才有作用。
        slider1.setPaintTicks(true);
       
        /*设置大刻度与小刻度之间的距离(setMajorTickSpacing()与setMinorTickSpacing()方法).例如若大刻度间距离为30，
         *小刻度间距离为10，则表示2个大刻度间会有3个小刻度.
         */
        slider1.setMajorTickSpacing(20);
        slider1.setMinorTickSpacing(10);

        //setPaintLabels()方法为设置是否数字标记，若设为true，则JSlider刻度上就会有数值出现。
        slider1.setPaintLabels(true);

        //setPaintTrack()方法表示是否出现滑动杆的横杆。默认值为true.
        slider1.setPaintTrack(true);

        //setSnapToTicks()方法表示一次移动一个小刻度，而不再是一次移动一个单位刻度。
        slider1.setSnapToTicks(true);

        label1 = new JLabel("目前刻度："+slider1.getValue());
        panel1.add(label1);
        panel1.add(slider1);
        panel1.setBorder(BorderFactory.createTitledBorder(
        BorderFactory.createEtchedBorder(),"Slider 1",TitledBorder.LEFT,
        TitledBorder.TOP));
       
        JPanel panel2 = new JPanel();
        panel2.setLayout(new GridLayout(2,1));
        slider2 = new JSlider(JSlider.HORIZONTAL);
        slider2.setMinimum(0);
        slider2.setMaximum(100);
        slider2.setValue(30);
        slider2.setExtent(50);
        slider2.setPaintTicks(true);
        slider2.setMajorTickSpacing(10);
        slider2.setMinorTickSpacing(2);
        slider2.setPaintLabels(true);

        /*JComponent提供了一个putClientProperty()方法，可以使得JSlider中的小于滑动杆位置与大于滑动杆位置间的颜色不
         *一样，这样的视觉效果会比较好，"JSlider.isFilled"值是定义在MetalSliderUI这个类的SLIDER_FILL常数中，此类是
         *定义在java的JSlider默认外观，你可以在javax.swing.plaf.metal.package中找到这个类。
         */
        slider2.putClientProperty("JSlider.isFilled",Boolean.TRUE);
        label2 = new JLabel("目前刻度："+slider2.getValue());
        panel2.add(label2);
        panel2.add(slider2);
        panel2.setBorder(BorderFactory.createTitledBorder(
        BorderFactory.createEtchedBorder(),"Slider 2",TitledBorder.LEFT,
        TitledBorder.TOP));
       
        JPanel panel3 = new JPanel();
        panel3.setLayout(new GridLayout(2,1));
        slider3 = new JSlider(20,80);
        slider3.setOrientation(JSlider.VERTICAL);
        slider3.setPaintTicks(true);
        slider3.setMajorTickSpacing(30);
        slider3.setMinorTickSpacing(10);
        slider3.setPaintLabels(true);
        slider3.putClientProperty("JSlider.isFilled",Boolean.TRUE);
        label3 = new JLabel("目前刻度："+slider3.getValue());
        panel3.add(label3);
        panel3.add(slider3);
        panel3.setBorder(BorderFactory.createTitledBorder(
        BorderFactory.createEtchedBorder(),"Slider 3",TitledBorder.LEFT,
        TitledBorder.TOP));
       
        slider1.addChangeListener(this);
        slider2.addChangeListener(this);
        slider3.addChangeListener(this);
       
        panel1.setPreferredSize(new Dimension(300,130));
        panel2.setPreferredSize(new Dimension(300,130));
        panel3.setPreferredSize(new Dimension(150,260));
       
        GridBagConstraints c;
        int gridx,gridy,gridwidth,
            gridheight,anchor,fill,ipadx,ipady;
        double weightx,weighty;
        Insets inset;    
       
        GridBagLayout gridbag = new GridBagLayout();
        contentPane.setLayout(gridbag);
       
        gridx=0;               //第0行
        gridy=0;               //第0列
        gridwidth = 2;         //占两单位宽度
        gridheight = 1;        //占一单位高度
        weightx = 0;          
        weighty = 0;          
        anchor = GridBagConstraints.CENTER;
        fill = GridBagConstraints.BOTH;    
        inset = new Insets(0,0,0,0);       
        ipadx = 0;                         
        ipady = 0;                         
        c = new GridBagConstraints(gridx,gridy,gridwidth,gridheight,
            weightx,weighty,anchor,fill,inset,ipadx,ipady);
        gridbag.setConstraints(panel1,c);
        contentPane.add(panel1);
       
        gridx=0;
        gridy=1;
        c = new GridBagConstraints(gridx,gridy,gridwidth,gridheight,
            weightx,weighty,anchor,fill,inset,ipadx,ipady);
        gridbag.setConstraints(panel2,c);
        contentPane.add(panel2);
       
        gridx=2;
        gridy=0;
        gridwidth = 1;         //占一单位宽度
        gridheight = 2;        //占两单位高度
        c = new GridBagConstraints(gridx,gridy,gridwidth,gridheight,
            weightx,weighty,anchor,fill,inset,ipadx,ipady);
        gridbag.setConstraints(panel3,c);
        contentPane.add(panel3);
       
        f.pack();
        f.setVisible(true);
       
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }
   
    public static void main(String[] args)
    {
        new SliderDemo2();
    }
   
    public void stateChanged(ChangeEvent e)
    {
        if ((JSlider)e.getSource() == slider1)
            label1.setText("目前刻度："+slider1.getValue());
        if ((JSlider)e.getSource() == slider2)
            label2.setText("目前刻度："+slider2.getValue());
        if ((JSlider)e.getSource() == slider3)
            label3.setText("目前刻度："+slider3.getValue());
    }
}

14-1-3:自定义JSlider标记名称:
   我们在上个范例中看到的JSlider标记都是数字形态，当然我们也可以自定义自己想要的标记文字，这时候就必须使用JSlider所
提供的setLabelTable()方法。我们来看下面的例子。
import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.event.*;
import java.util.*;

public class SliderDemo3 implements ChangeListener
{
    JFrame f = null;
    JSlider slider1;
    JSlider slider2;
    JSlider slider3;
    JLabel label1;
    JLabel label2;
    JLabel label3;
   
    public SliderDemo3()                          
    {
        f = new JFrame("JSlider Example");
        Container contentPane = f.getContentPane();
       
        JPanel panel1 = new JPanel();
        panel1.setLayout(new GridLayout(2,1));
        slider1 = new JSlider();
        slider1.setPaintTicks(true);
        slider1.setMajorTickSpacing(20);
        slider1.setMinorTickSpacing(10);
        slider1.setPaintLabels(true);
        slider1.setPaintTrack(true);
        slider1.setSnapToTicks(true);
        label1 = new JLabel("目前刻度："+slider1.getValue());
        panel1.add(label1);
        panel1.add(slider1);
        panel1.setBorder(BorderFactory.createTitledBorder(
        BorderFactory.createEtchedBorder(),"Slider 1",TitledBorder.LEFT,
        TitledBorder.TOP));
       
        Hashtable table = new Hashtable();
        table.put(new Integer( 0 ),new JLabel("低"));
        table.put(new Integer( 50 ),new JLabel("中"));
        table.put(new Integer( 100 ),new JLabel("高"));
        slider1.setLabelTable(table);
       
        JPanel panel2 = new JPanel();
        panel2.setLayout(new GridLayout(2,1));
        slider2 = new JSlider(JSlider.HORIZONTAL);
        slider2.setMinimum(0);
        slider2.setMaximum(100);
        slider2.setValue(30);
        slider2.setExtent(50);
        slider2.setPaintTicks(true);
        slider2.setMajorTickSpacing(10);
        slider2.setMinorTickSpacing(5);
        slider2.setPaintLabels(true);
        slider2.putClientProperty("JSlider.isFilled",Boolean.TRUE);
        label2 = new JLabel("目前刻度："+slider2.getValue());
        panel2.add(label2);
        panel2.add(slider2);
        panel2.setBorder(BorderFactory.createTitledBorder(
        BorderFactory.createEtchedBorder(),"Slider 2",TitledBorder.LEFT,
        TitledBorder.TOP));
       
        table = new Hashtable();
        table.put(new Integer( 0 ),new JLabel("弱"));
        table.put(new Integer( 25 ),new JLabel("有点弱"));
        table.put(new Integer( 50 ),new JLabel("中"));
        table.put(new Integer( 75 ),new JLabel("有点强"));
        table.put(new Integer( 100 ),new JLabel("强"));
        slider2.setLabelTable(table);
       
        JPanel panel3 = new JPanel();
        panel3.setLayout(new GridLayout(2,1));
        slider3 = new JSlider(20,80);
        slider3.setOrientation(JSlider.VERTICAL);
        slider3.setPaintTicks(true);
        slider3.setMajorTickSpacing(30);
        slider3.setMinorTickSpacing(10);
        slider3.setPaintLabels(true);
        slider3.putClientProperty("JSlider.isFilled",Boolean.TRUE);
        label3 = new JLabel("目前刻度："+slider3.getValue());
        panel3.add(label3);
        panel3.add(slider3);
        panel3.setBorder(BorderFactory.createTitledBorder(
        BorderFactory.createEtchedBorder(),"Slider 3",TitledBorder.LEFT,
        TitledBorder.TOP));
       
        slider1.addChangeListener(this);
        slider2.addChangeListener(this);
        slider3.addChangeListener(this);
       
        panel1.setPreferredSize(new Dimension(300,130));
        panel2.setPreferredSize(new Dimension(300,130));
        panel3.setPreferredSize(new Dimension(150,260));
       
        GridBagConstraints c;
        int gridx,gridy,gridwidth,
            gridheight,anchor,fill,ipadx,ipady;
        double weightx,weighty;
        Insets inset;    
       
        GridBagLayout gridbag = new GridBagLayout();
        contentPane.setLayout(gridbag);
       
        gridx=0;               //第0行
        gridy=0;               //第0列
        gridwidth = 2;         //占两单位宽度
        gridheight = 1;        //占一单位高度
        weightx = 0;          
        weighty = 0;         
        anchor = GridBagConstraints.CENTER;
        fill = GridBagConstraints.BOTH;    
        inset = new Insets(0,0,0,0);       
        ipadx = 0;                         
        ipady = 0;                         
        c = new GridBagConstraints(gridx,gridy,gridwidth,gridheight,
            weightx,weighty,anchor,fill,inset,ipadx,ipady);
        gridbag.setConstraints(panel1,c);
        contentPane.add(panel1);
       
        gridx=0;
        gridy=1;
        c = new GridBagConstraints(gridx,gridy,gridwidth,gridheight,
            weightx,weighty,anchor,fill,inset,ipadx,ipady);
        gridbag.setConstraints(panel2,c);
        contentPane.add(panel2);
       
        gridx=2;
        gridy=0;
        gridwidth = 1;         //占一单位宽度
        gridheight = 2;        //占两单位高度
        c = new GridBagConstraints(gridx,gridy,gridwidth,gridheight,
            weightx,weighty,anchor,fill,inset,ipadx,ipady);
        gridbag.setConstraints(panel3,c);
        contentPane.add(panel3);
       
        f.pack();
        f.setVisible(true);
       
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }
   
    public static void main(String[] args)
    {
        new SliderDemo3();
    }
   
    public void stateChanged(ChangeEvent e)
    {
        if ((JSlider)e.getSource() == slider1)
            label1.setText("目前刻度："+slider1.getValue());
        if ((JSlider)e.getSource() == slider2)
            label2.setText("目前刻度："+slider2.getValue());
        if ((JSlider)e.getSource() == slider3)
            label3.setText("目前刻度："+slider3.getValue());
    }
}

说明：要改变标记值必须使用setLabelTable(Dictionary table)方法，参数Dictionary本身是一个抽象类，我们并不能直接就new
      出一个Dictionary对象，而必须使用它的子类Hashtable来产生Dictionary类型的对象。Hashtable存储信息的方式是以
      key-value pair类型来存储，换名话说，当你要找某个对象时，你就必须知道此对象的key值。而在此例中，我们要换原有
      JSlider上的文字，必须指明那个数字要理发成什么文字。例如table.put(new Integer(0)),new JLabel("弱"))就表示数字
      0要变更成文字"弱",在Hashtable中，Integer(0)就是对象JLabel("弱")的key值。

14-2:使用Timer组件：
   java.lang.Object
    --javax.swing.Timer
   使用Timer组件可以让你在一段时间内依次做出你指定的操作，这在动画的展示上非常有用。如果你有用过如ACDsee这类的看图
软件，你可以发现这类软件都会提供一种功能，那就是自动换图的功能，而且也可以让你设置换图时间间隔的长短。在java中，
swing的Timer组件就可以让你做到这样的功能，而且非常容易使用，下面我们先来看Timer的构造函数。

Timer构造函数：
Timer(int delay,ActionListener listener):建立一个Timer组件，并在每一次delay的时间点上触发ActionEvent.
          使用Timer组件它会在根据你所给予的delay时间，周期性的触发ActionEvent事件，如果你要处理这个事件，你必须实作
ActionListener界面所定义的actionPerformed()方法。要开始激活Timer组件，你可以用start()方法，要停止Timer组件可以使用
stop()方法，要从新激活Timer组件可以使用restart()方法，若只想Timer组件只触发一次ActionEvent事件，可利用
setRepeats(false)方法，将参数设为false，若要设置delay时间则可用setDelay()方法。
    事实上使用Timer组件表示在程序背后是利用Threads在运行Timer的工作，因此你当然也可以利用Thread的功能来自行制造出这
样的效果，不过这不在本书的讨论范围内，下面的范例我们实作一个显示图程序，可让用户调整显示图时间的快慢。

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

public class TimerDemo1 implements ActionListener,ChangeListener
{
    JFrame f = null;
    ImageIcon[] icons;
    JSlider slider1;
    JLabel label;
    JToggleButton toggleb1,toggleb2;
    JButton b;
    javax.swing.Timer timer;
    int index = 0;
   
    public TimerDemo1()                          
    {
        f = new JFrame("Timer Example");
        Container contentPane = f.getContentPane();
        icons = new ImageIcon[5];
        for (int i=0 ; i<5 ; i++)
            icons[i] = new ImageIcon(".\\icons\\"+(i+1)+".jpg");
       
        label = new JLabel(icons[0]);
        JPanel panel1 = new JPanel();
        panel1.setLayout(new GridLayout(2,1));
        slider1 = new JSlider();
        slider1.setPaintTicks(true);
        slider1.setMajorTickSpacing(20);
        slider1.setMinorTickSpacing(10);
        slider1.setPaintLabels(true);
        slider1.addChangeListener(this);
        panel1.add(slider1);
       
        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout(new GridLayout(1,3));
        toggleb1 = new JToggleButton("Start");
        toggleb1.addActionListener(this);
        buttonPanel.add(toggleb1);
        b = new JButton("Restart");
        b.addActionListener(this);
        buttonPanel.add(b);
        toggleb2 = new JToggleButton("Don't Repeat");
        toggleb2.addActionListener(this);
        buttonPanel.add(toggleb2);
        panel1.add(buttonPanel);
       
        Hashtable table = new Hashtable();
        table.put(new Integer( 0 ),new JLabel("е"));
        table.put(new Integer( 50 ),new JLabel("い"));
        table.put(new Integer( 100 ),new JLabel("篊"));
        slider1.setLabelTable(table);
        /*由于java的Timer组件有两种，一种是javax.swing.Timer,一种是java.util.Timer,若我们在程序中import了这两种
         *package,则系统将不晓得到底要产生哪种Timer组件，就如同本范例一般，因此我们必须在new Timer组件的同时，指
         *定要new出哪一种类型的Timer组件。因此我们必须在new Timer组件的同时，指定要new出哪一种类型的Timer组件，在
         *此我们当然是要产生Swing的Timer组件，在此我们当然是要产生Swing的Timer组件。
         */
        timer = new javax.swing.Timer(slider1.getValue()*10,this);
       
        contentPane.add(label,BorderLayout.CENTER);
        contentPane.add(panel1,BorderLayout.SOUTH);
       
        f.pack();
        f.setVisible(true);
       
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }
   
    public static void main(String[] args)
    {
        new TimerDemo1();
    }
    //处理按钮事件与Timer事件。
    public void actionPerformed(ActionEvent e)
    {
        if (e.getSource() == toggleb1)
        {//当用户按下"start"按钮时，Timer开始运行，且"Start"按钮会变成"Stop",若用户再次按下"stop"按钮，则Timer暂停
         //运行，且"stop"按钮变成"start".
            if (e.getActionCommand().equals("Start"))
            {  
                timer.start();
                toggleb1.setText("Stop");
            }
            if (e.getActionCommand().equals("Stop"))
            {  
                timer.stop();
                toggleb1.setText("Start");
            }
        }
        //当用户按下"Don't Repeat"按钮时，则Timer事件只触发一次，若再按一次"Don't Repeat"按钮，则Timer继续运行。
        if (e.getSource() == toggleb2)
        {
            if(timer.isRepeats())
            {
                timer.setRepeats(false);
            }
            else
            {
                timer.setRepeats(true);
                timer.start();
            }
        }
        //当用户按下"Restart"按钮时，则Timer组件的delay值恢复成初如值，并重新运行Timer.
        if (e.getSource() == b)
        {
            slider1.setValue(50);
            timer.restart();
        }
        //处理Timer产生的ActionEvent事件，每次时间一到delay所设置的时间,label上的图片就会更换一次。
        if (e.getSource() == timer)
        {
            if (index == 5)
                index = 0;
            label.setIcon(icons[index]);
            label.repaint();
            //f.pack(); //若要窗口随图形大小变化，可加入此行.
            index++;
        }
    }
     //处理slider所产生的ChangeEvent事件，当用户移动slider1的滑动杆时，等于从新设置Timer的delay时间。      
    public void stateChanged(ChangeEvent e1)
    {
            timer.setDelay(slider1.getValue()*10);
    }
}

14－3：使用Progress Bar组件：
JProgressBar的类层次结构图：
  java.lang.Object
   --java.awt.Component
     --java.awt.Container
      --javax.swing.JComponent
       --javax.swing.JProgressBar
   当你在安装一个新软件时，系统会告知你目前软件安装的进度如何？才不会让你觉得程序好像死了，同样的，若你设计的程序所
需要的运行超过2秒以上，你应该显示程序正在运行中的图标，或直接显示程序运行的进度，这样就能让用户清楚知道程序到底是死
了还是继续运行，在swing中，JProgressBar组件提供了类似这样的功能，它可以簋简单地输出进度的变化情况，让你想要提供进度
信息时，不再需要自行绘制绘图组件，只需要使用JProgressBar再加上几行程序设置就可以了。以下是JProgressBar的范例，在此
范例中，我们使用Timer组件当作控制进度杆移动的速度，当用户按下"start"按钮，则进度杆线就会开始向右移动，并显示出目前
的进度信息。每当JProgressBar的值改变一次（利用setValue()方法），就会触发一次ChangeEvent事件，如果你要处理这个事件，
你必须实作ChangeListener界面所定义的stateChanged()方法，在此我们是将JPogressBar的移动信息放在label上。

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

public class ProgressBarDemo implements ActionListener,ChangeListener
{
    JFrame f = null;
    JProgressBar progressbar;
    JLabel label;
    Timer timer;
    JButton b;
   
    public ProgressBarDemo()                          
    {
        f = new JFrame("progressbar Example");
        Container contentPane = f.getContentPane();
       
        label = new JLabel(" ",JLabel.CENTER);
        progressbar = new JProgressBar();
        progressbar.setOrientation(JProgressBar.HORIZONTAL);
        progressbar.setMinimum(0);
        progressbar.setMaximum(100);
        progressbar.setValue(0);
        progressbar.setStringPainted(true);
        progressbar.addChangeListener(this);
        progressbar.setPreferredSize(new Dimension(200,30));
        progressbar.setBorderPainted(false);
       
        JPanel panel = new JPanel();
        b = new JButton("Start");
        b.addActionListener(this);
        panel.add(b);
       
        timer = new Timer(50,this);
       
        contentPane.add(panel,BorderLayout.NORTH);
        contentPane.add(progressbar,BorderLayout.CENTER);
        contentPane.add(label,BorderLayout.SOUTH);
       
        f.pack();
        f.setVisible(true);
       
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
    }
   
    public static void main(String[] args)
    {
        new ProgressBarDemo();
    }
   
    public void actionPerformed(ActionEvent e)
    {
        if(e.getSource() == b)
        {
            timer.start();
        }
           
        if(e.getSource() == timer)
        {
            int value = progressbar.getValue();

            if( value < 100)
            {
                value++;
                progressbar.setValue(value);
            }
            else
            {
                timer.stop();
                progressbar.setValue(0);
            }
        }
    }
           
    public void stateChanged(ChangeEvent e1)
    {
        int value = progressbar.getValue();
       
        if(e1.getSource() == progressbar)
        {
            label.setText("目前已完成进度："+Integer.toString(value)+" %");
        }
    }
}