xlcd.java

黑白交错等多个程序。

import java.awt.*;
import java.awt.*;
public class Xlcd extends java.applet.Applet implements
ItemListener,ActionListener
{
	Choice choice;
	TextField text;
	TextArea  area;
	Button   add;
	Button   del;

	public void init()
	{  	setLayout(new GridLayout(3,1));
		choice=new Choice();
		text=new TextField(12);
		area=new TextArea("S",20,10,TextArea.SCROLLBARS_BOTH);
		add=new Button("添加");
		del=new Button("删除");

		choice.add("音乐天地");
		choice.add("清华大学");
		choice.add("北京大学");
		choice.add("学友之旅");

		Panel p1=new Panel();
		Panel p2=new Panel();
		Panel p3=new Panel();

		add(p1,"North");
		add(p2,"Center");
		add(p3,"South");

		p1.add(choice);
		p1.add(del);
		p2.add(text);
		p2.add(add);
		p3.add(area);

		choice.addItemListener(this);
		add.addActionListener(this);
		del.addActionListener(this);

	}

	public void itemStateChanged(ItemEvent e)
	{
	   String name=choice.getSelectedItem();
	   int  index=choice.getSelectedIndex();

	   area.setText("\n"+index+":"+name+"\n");
	}

	public void actionPerformed(ActionEvent e)
	{
		if (e.getSource()==add||e.getSource()==text)
    	{
		String str=text.getText();
		if(str.length()>0)
		{
		choice.add(str);
		area.append("\n"+"增加"+str);
		choice.select(str);
		}
		}

		if (e.getSource()==del)
	   {String st=choice.getSelectedItem();
		choice.remove(st);
		area.append("\n"+"删除"+st);
	   }
	}
}