下面是一个Applet程序,程序的功能是用鼠标画图。本题是通过单击鼠标后画出一个Java字。请改正程序中的错误(有下划线的语句),使程序能输出正确的结果。
注意;不改动程序的结构,不得增行或减行。
源程序文件代码清单如下;
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
/*
<applet code=SimpleHitMouse.java width=800 height=400>
</applet>
*/
public class SimpleHitMouse implements Applet
private java.util.Vector points=new java.util.Vector();
public void init()
addMouseListener(new MouseAdapter()
public void mousePressed(MouseEvent e)
points.add(new Point(e.getX(),e.getY())
paint();
);
public void update(Graphics g)
repaint(g);
public void paint(Graphics g)
for(int i=0;i<points.size();i++)
Point dot=(Point)points.elementAt(i);
g.drawString("x",dot.x,dot.y);
public static void main(String args[ ])
Frame fram=new Frame("CelayTree");
SimpleHitMouse dot=new SimpleHitMouse();
dot.init ();
dot.start ();
fram.add ( "Center", dot );
fram.setSize( 400,300 );
fram.addWindowListener( new WindowAdapter()
public void windowClosing( WindowEvent e )
System.exit(0);
);
fram.show ();
ex12_3.html:
<html>
<head>
<title>A Simple Program</title>
</head>
<body>
<applet code=" SimpleHitMouse.class" width=800 height=400>
</applet>
</body>
</html>