table.java

控制盒子左右上下移动

import java.awt.*;
import java.awt.event.*;
public class Table extends Frame implements ActionListener
{private Button quit=new Button("Quit");
 private Button start=new Button("Start");
 private Button stop=new Button("Stop");
 private Marble marbles[]=new Marble[20];
 public Table()
 {super("Table with marbles");
 setLayout(new FlowLayout());
 add(quit); quit.addActionListener(this);
 add(start);start.addActionListener(this);
 add(stop);stop.addActionListener(this);
 validate();setSize(300,300);
 setVisible(true);
 for(int i=0;i<marbles.length;i++)
 { int x=(int)(getSize().width*Math.random());
   int y=(int)(getSize().height*Math.random());
  marbles[i]=new Marble(this,x,y);  
}
}
public void actionPerformed(ActionEvent ae)
{if (ae.getSource()==stop)
for(int i=0;i<marbles.length;i++)
marbles[i].halt();
 
 if(ae.getSource()==start)
 for(int i=0;i<marbles.length;i++)
 {marbles[i].halt();
 marbles[i]=new Marble(this,marbles[i].x,marbles[i].y);
}
 
 if(ae.getSource()==quit)
 System.exit(0);
}
public void paint(Graphics g)
{for(int i=0;i<marbles.length;i++)
if(marbles[i]!=null)
draw(g);}
public void draw(Graphics g)
{g.setColor(Color.black);
 g.fillOval(Marble.x,Marble.y,20,20);}
public static void main(String args[])
{Table table=new Table();}
}