hw16_11.java

java的一些关于多线程

import java.awt.*;
import java.awt.event.*;
public class hw16_11 extends Frame implements ItemListener
{
   static hw16_11 frm=new hw16_11(); 
   static Checkbox ckb1=new Checkbox("Green");
   static Checkbox ckb2=new Checkbox("Blue");
   static Checkbox ckb3=new Checkbox("Yellow");   
   
   public static void main(String args[])  
   {
      CheckboxGroup grp=new CheckboxGroup();
      frm.setSize(200,150);
      frm.setTitle("Item Event");
      frm.setLayout(null);
      ckb1.setBounds(20,40,80,20);
      ckb2.setBounds(20,60,80,20);
      ckb3.setBounds(20,80,80,20); 
      ckb1.setCheckboxGroup(grp);  
      ckb2.setCheckboxGroup(grp);  
      ckb3.setCheckboxGroup(grp);      
      ckb1.addItemListener(frm);    
      ckb2.addItemListener(frm); 
      ckb3.addItemListener(frm);             
      frm.add(ckb1);
      frm.add(ckb2); 
      frm.add(ckb3);
      frm.setVisible(true); 
   }

   public void itemStateChanged(ItemEvent e) 
   {
      if(ckb1.getState()==true)           
         frm.setBackground(Color.green);
      else if(ckb2.getState()==true)   
         frm.setBackground(Color.blue);
      else
         frm.setBackground(Color.yellow);    
   }
}