counterthreadapplet.java

中国水利水电出版社java程序设计教程,附源码

//CounterThreadApplet.java

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

public class CounterThreadApplet extends JApplet implements Runnable
{
//控制记数文本框是否继续记数。
	private boolean countFlag=true;

//记数窗口已经显示的文本框数目。
	private int number = 0;

	private JPanel textPanel = new JPanel();
	private Container contentPane;
	private JFrame counterFrame;
	public static final int WIDTH = 450;
	public static final int HEIGHT = 350;

	public void init()
	{
//弹出记数窗口。
		counterFrame = new JFrame();
		counterFrame.setTitle("CounterThreadAppletFrame");
		counterFrame.setSize(WIDTH, HEIGHT);
		contentPane = counterFrame.getContentPane();
		
		JPanel buttonPanel = new JPanel();
//增加记数文本框的按钮。
		addButton(buttonPanel, "Add",
			new ActionListener()
			{
				public void actionPerformed(ActionEvent evt)
				{
					countFlag = true;
					startCount();
				}
			}
		);

//停止记数按钮，并关闭窗口。
		addButton(buttonPanel, "Close",
			new ActionListener()
			{
				public void actionPerformed(ActionEvent evt)
				{
					stopCount();
				}
			}
		);

		contentPane.add(buttonPanel, BorderLayout.SOUTH);
		counterFrame.show();
	}

	public void startCount()
	{
//受窗口大小限制，控制能够增加的文本框的数量为16个。
		if(number >= 16)
		{
			return;
		}
		number++;

//生成新线程。
		Thread counterRunner = new Thread(this);
		counterRunner.start();
	}

	public void stopCount()
	{  
		if (countFlag)
		{
			countFlag = false;
		}
		showStatus("stop counting!");
//关闭窗口
		counterFrame.dispose();
	}

	public void run()
	{

		TextField textField = new TextField(20);
		textPanel.add(textField);
		contentPane.add(textPanel, BorderLayout.NORTH);
		counterFrame.show();

//循环50次，每次递增1。
		for (int i = 0; i < 50; i++)
		{
			try
			{
				if(countFlag) 
					textField.setText(Integer.toString(i));
//暂时停止当前线程50毫秒。
				Thread.sleep(50);
			}
			catch (InterruptedException e)
			{
			}
		}
	}

	public void addButton(Container c, String title, ActionListener 
							listener)
	{
		JButton button = new JButton(title);
		c.add(button);
		button.addActionListener(listener);
	}
}