填空题 【说明】 以下程序实现了利用鼠标任意移动该圆形的位置，仔细阅读代码和相关注释，将程序补充完整。 【代码6】 import java.awt.*; import java.awt.event.*; public class CIUSAMPLE extends Frame implements MouseMotionListener, MouseListener { static CIUSAMPLE frm=new CIUSAMPLE (); int x=70,y=60,posX=70,posY=60,dx,dy; public static void main ( String args[]) { frm.setTitle ("Dragging a circle"); frm.setSize ( 200,150 ); {{U}} (1) {{/U}} frm.addMouseMotionListener ( frm ); frm. setVisible ( true ); } public void mousePressed ( MouseEvent e ) { {{U}} (2) {{/U}} dy=e.getY () -posY; } public void mouseDragged ( MouseEvent e ) { {{U}} (3) {{/U}} y=e.getY () -dy; if ( dx＞0 && dx＜50 && dy＞0 && dy＜50 ) //如果指我落在正方形区域内 { Graphics g=getGraphics (); {{U}} (4) {{/U}} } } public void paint ( Graphics g ) { g.setColor ( Color. pink ); // 设置绘图颜色为粉红 g.fillOval ( x,y,50,50 ); //以基准点为图形的左上角绘出圆形 {{U}} (5) {{/U}} posY=y; } 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 ) { } }