jprogressbardemo.java

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import java.awt.*;
import javax.swing.*;
import java.awt.event.*;       
public class JProgressBarDemo extends JFrame 
{
	private JProgressBar progressBar;            //进度条
	private JButton startButton, stopButton;     //启动, 暂停, 重启动按钮
    private Timer timer;                         //定时器    
    public JProgressBarDemo() 
    {
       super("滚动条");
       setSize(300, 200);
       
	   //获取内容面板
       Container container = getContentPane();
       //设置内容面板的布局管理器
       container.setLayout(new FlowLayout(FlowLayout.CENTER));
       container.setBackground(Color.YELLOW);
       
       //创建进度条
       progressBar = new JProgressBar();
       
       //设置最小值,最大值,初值
       progressBar.setMinimum(0);
       progressBar.setMaximum(100);
       progressBar.setValue(0);
       //显示进度条进度文本
       progressBar.setStringPainted(true);
       //显示进度条边框
       progressBar.setBorderPainted(true);
       
       //设置进度条大小,背景色,前景色
       progressBar.setPreferredSize(new Dimension(250,30));
       progressBar.setBackground(Color.WHITE);
       progressBar.setForeground(Color.GREEN);
       
       container.add(progressBar);
       
       //创建按钮
       startButton = new JButton("开始");
	   stopButton = new JButton("暂停");
	   //设置按钮背景颜色
	   startButton.setBackground(Color.WHITE);
	   stopButton.setBackground(Color.WHITE);
	   //设置字体
	   startButton.setFont(new Font("Serif", Font.PLAIN, 14));
	   stopButton.setFont(new Font("Serif", Font.PLAIN, 14));
	   
	   stopButton.setEnabled(false);
		
	   //注册监听器
	   TimerHandler handler = new TimerHandler();
	   startButton.addActionListener(handler);
	   stopButton.addActionListener(handler);
       
	   container.add(startButton);
	   container.add(stopButton);
	   
       //创建定时器,时间间隔为50毫秒,设置监听器
       timer = new Timer(50, handler);
       
       setVisible(true);
       setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public static void main(String args[]) 
    {
       JProgressBarDemo application = new JProgressBarDemo();
    }
    
    class TimerHandler implements ActionListener
    {
    	//处理定时器事件
    	private int value = 0;
        public void actionPerformed(ActionEvent event)
        {
        	if(event.getSource() == timer)
        	{
        		value = progressBar.getValue();
        		if( value < 100)
        		{
        			value++;
                    progressBar.setValue(value);
                } 
                else
                {
                  timer.stop();
                  startButton.setEnabled(true);
                  stopButton.setEnabled(false);
                }
            }
            else if(event.getSource() == startButton)
            {
                if(progressBar.getValue() >= 100)
                	progressBar.setValue(0);
                timer.start();
                startButton.setEnabled(false);
                stopButton.setEnabled(true);
         	}
         	else if(event.getActionCommand().equals("暂停"))
         	{
         		timer.stop();
         		stopButton.setText("重启动");
         	}
         	else if(event.getActionCommand().equals("重启动"))
         	{
         		timer.restart();
         		stopButton.setText("暂停");
         	}
        }          
    }                    //TimerHandler类结束  
}