import java.applet.*;
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
import java.util.*;
public class HuaYuan extends JApplet{
public void init(){
setLayout(new FlowLayout());
Button bt=new Button("wo");
add(bt);
setForeground(Color.blue);
setBackground(Color.white);
addMouseListener(new CListener());

}
class CListener extends MouseAdapter{
private Random b=new Random();
private int i=b.nextInt()%100;
public void mousePressed(MouseEvent me){

JApplet a= (JApplet)me.getSource();
Graphics g=a.getGraphics();
g.fillOval(me.getX()-i,me.getY()-i,2*i,2*i);
}
}
public static void main(String[] args){
JFrame frm=new JFrame();
frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frm.setSize(220,120);
HuaYuan hy=new HuaYuan();
frm.add(hy);
hy.init();
hy.start();
frm.setVisible(true);

}

}
问什么变量i必须得是private才行啊，还有我怎么能够让它每次画的半径都不相同 并且让它不会因为frame的大小发生变化而没有了。