[说明] 以下程序实现了利用鼠标任意移动圆形的位置，仔细阅读代码和相关注释，将程序补充完整。 [代码6-1] 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); (1) ffm.addMouseMotionListener (frm);frm.setVisible (true); } public void mousePressed (MouseEvent e) { (2) dy=e.getY ( ) -posY; } public void mouseDragged (MouseEvent e) { (3) y=e.getY ( ) -dy; if(dx＞0&&dx＜50&&dy＞0&&dy＜50) //如果指针落在正方形区域内 {Graphicsg=getGraphics ( ); (4) } } public void paint (Graphics g) { g.setColor (Color.pink); //设置绘图颜色为粉红 g.fillOval(x,y,50,50); //以基准点为图形在左上角绘出圆形(5) 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) {} }

退火(annealing)