问答题

[说明]
以下程序实现了在applet里移动图形文件，仔细阅读代码和相关注释，将程序补充完整。
[代码6-1]
import j ava. awt. *;
import j ava.awt.event.*;
import java.applet. Applet;
public class AppCIU extends Applet implements MouseMotionListener, MouseListener

Image img; // 声明 Image 类类型的变量 img
int x=70,y=60,posX=70,posY=60,dx,dy;
public void init ( )

img=getImage ( getCodeBase ( ) ,"mouse.gif" ); //载入影像
addMouseListener ( this );
addMouseMotionListener ( this );
　
public void mousePressed ( MouseEvent e )

dx=e.getX()-posX； //取得按下之点与基准点X方向的距离
dy=e.getY()-posY； //取得按下之点与基准点Y方向的距离

public void mouseDragged ( MouseEvent e )

(1)
(2)
if ( dx＞0 && dx＜120 && dy＞0 && dy＜60 ) //如果指针落在图形上方

Graphics g=getGraphics ( );
(3)


public void paint ( Graphics g )

(4)
(5)
(6)

public void mouseMoved ( MouseEvent e ) ;
public void mouseReleased ( MouseEvent e ) ;
public void mouseEntered ( MouseEvent e ) ;
public void mouseExited ( MouseEvent e ) ;
public void mouseClicked ( MouseEvent e ) ;