import java.awt.*;
import java.awt.event.*;
public class Eventest
{
    Button btn1=new Button("单击");
    Frame myframe=new Frame("测试单击事件");
    public void init(){
        btn1.setSize(30,26);
        btn1.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                if(btn1.getBackground()==Color.red)
                    btn1.setBackground(Color.white);
                  else
                  btn1.setBackground(Color.red);
            }
        });
        myframe.setBounds(300,200,200,200);
        myframe.add(btn1);
        myframe.setVisible(true);

    }

    public static void main(String[] args)
    {
        new Eventest().init();
    }
}