import java.applet.*;import java.awt.*;import java.awt.event.*;public class Example18_13 extends Applet implements KeyListener,ActionListener{Label label=new Label("點(diǎn)擊一個(gè)積木，然后移動(dòng)它"); Button b[]=new Button[40]; int x[]=new int[40]; int y[]=new int[40]; String s=null; public void init() { setLayout(null);   add(label);   label.setBounds(0,0,150,30);   int k1=70,k2=70,k3=70,k4=70;  for(int i=0;i<40;i++)  {b[i]=new Button(String.valueOf(i));   if(i%3==0) b[i].setBackground(Color.red);   if(i%3==1) b[i].setBackground(Color.blue);   if(i%3==2) b[i].setBackground(Color.yellow);   b[i].addKeyListener(this);//按鈕獲得鍵盤事件監(jiān)視器.   b[i].addActionListener(this); add(b[i]);   if(i%4==0)         {b[i].setBounds(k1,40,30,30);k1=k1+31;}   else if(i%4==1)  {b[i].setBounds(k2,71,30,30);k2=k2+31;}   else if(i%4==2)  {b[i].setBounds(k3,102,30,30);k3=k3+31;}   else if(i%4==3)  {b[i].setBounds(k4,133,30,30);k4=k4+31;}  }  for(int i=0;i<40;i++)  { x[i]=b[i].getBounds().x;y[i]=b[i].getBounds().y;//獲取按鈕左上角的x,y坐標(biāo)。  } } public void keyTyped(KeyEvent e) { }  public void keyPressed(KeyEvent e) {if(e.getKeyCode()==KeyEvent.VK_UP)    {for(int i=0;i<=39;i++)      { if(s.equals(String.valueOf(i)))        {y[i]=y[i]-2;         if(y[i]<=0) y[i]=0;         b[i].setLocation(x[i],y[i]);        }      }    } else if(e.getKeyCode()==KeyEvent.VK_DOWN)    {for(int i=0;i<=39;i++)      {if(s.equals(String.valueOf(i)))        {y[i]=y[i]+2;        if(y[i]>=300) y[i]=300;        b[i].setLocation(x[i],y[i]);         }      }    } else if(e.getKeyCode()==KeyEvent.VK_LEFT)    {for(int i=0;i<=39;i++)      {if(s.equals(String.valueOf(i)))       {x[i]=x[i]-2;        if(x[i]<=0) x[i]=0;        b[i].setLocation(x[i],y[i]);       }      }    }  else if(e.getKeyCode()==KeyEvent.VK_RIGHT)    {for(int i=0;i<=39;i++)      {if(s.equals(String.valueOf(i)))       {x[i]=x[i]+2;        if(x[i]>=300) x[i]=300;        b[i].setLocation(x[i],y[i]);       }      }    }   } public void keyReleased(KeyEvent e) {} public void actionPerformed(ActionEvent e) { for(int i=0;i<40;i++)   {if(e.getSource()==b[i])     s=b[i].getLabel();   } }}