第2周：Java程序事件处理

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class simpleEvent extends Applet implements ActionListener
{
Label lb;
TextField in,out;
public void init()
{
lb = new Label("请输入您的名字");
in =new TextField(6);
out = new TextField(20);
add(lb);
add(in);
add(out);
in.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{
out.setText(in.getText()+"欢迎光临！");
}
}

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class ButtonDemo extends Applet implements ActionListener
{
String msg ="";
//定义按钮 "是"、"否"、"取消"
public void init()
{
Button yes = new Button("是");
Button no = new Button("否");
Button maybe = new Button("取消");
add(yes);
add(no);
add(maybe);
yes.addActionListener(this);
no.addActionListener(this);
maybe.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{
String str =e.getActionCommand();
if(str =="是")
{
msg ="您单击了按钮'是'。";
}
else if(str =="否")
{
msg ="您单击了按钮'否'。";
}
else
{
msg ="您单击了按钮'取消'。";
}
repaint();
}
public void paint(Graphics g)
{
g.drawString(msg,6,100);
}
}