toolbar.java

本程序为模拟工具条

import java.awt.*;
import java.net.*;
import java.applet.*;
import java.awt.event.*;
import java.util.StringTokenizer;

public class ToolBar extends Applet implements MouseListener{

   private  MediaTracker tracker;
  
   private  Image onImage, offImage;
   private  boolean onButt = false;
   private  boolean clickbutton = false;
   private  int onIs = 0;
   private  URL url;
   private  String dest, arg, target;

   public void init(){
      
      if ((arg = getParameter("target")) != null)
         target = arg;
      else
         target = null;

      tracker = new MediaTracker(this);
      onImage  = getImage(getDocumentBase(), getParameter("onImage"));
      tracker.addImage(onImage, 0);
      offImage = getImage(getDocumentBase(), getParameter("offImage"));
      tracker.addImage(offImage, 0);
      
      try {
         tracker.waitForAll();
      } catch (InterruptedException e) {}
             
      dest = getParameter("dest");
      try{
         url = new URL(getDocumentBase(), dest);
         System.out.println(dest);
      }catch(MalformedURLException mal){}
      addMouseListener(this);
   }
             
   public void start(){   
      repaint();
   }
     

   public void mouseClicked(MouseEvent e){
    
   }
   
   public void mousePressed(MouseEvent e){
      clickbutton = true;
      repaint();

   }
   
   public void mouseReleased(MouseEvent e){
   
      if(clickbutton && onButt){
         clickbutton = false;
         repaint();
      
         if (target != null)
            getAppletContext().showDocument(url, target);
         else 
            getAppletContext().showDocument(url);
      }else{
   
         clickbutton = false;
         repaint();
      }
    
   }
   
   public void mouseEntered(MouseEvent e){
       onButt = true;
       repaint();    
   }
   
   public void mouseExited(MouseEvent e){
   
    onButt = false;
    repaint();
    
   }

   
   public void drawPic(Graphics g, Image theImage){
      int a; 
      if (onIs == 3) 
         a = 1;
      else
         a =0;         
      int imageWidth    = theImage.getWidth(this);
      int imageHeight   = theImage.getHeight(this);
      int imageX = (getSize().width / 2) -  (imageWidth / 2);
      int imageY = (getSize().height / 2) - (imageHeight / 2); 

       imageY = (getSize().height / 2) - ( imageHeight  / 2 ) + 2;
         g.drawImage(theImage, imageX+a, imageY+a, this);

   }  
      
   public void drawButton(Graphics g){
   
      Color topAndLeft;
      Color bottomAndRight;
      
      if (onIs == 2){  
         topAndLeft  = Color.lightGray;
         bottomAndRight = Color.darkGray;
      }
      else{
        topAndLeft     = Color.darkGray;
         bottomAndRight = Color.lightGray;
      }
      

      g.setColor(topAndLeft);
      g.drawLine(0, 0, getSize().width, 0);
      g.drawLine(0, 1, 0, getSize().height);      
      g.setColor(bottomAndRight);
      g.drawLine(getSize().width - 1, 1, getSize().width - 1, getSize().height);
      g.drawLine(1, getSize().height - 1, getSize().width, getSize().height - 1);

   }
   
   public void paint(Graphics g){  
   
      if(!onButt){
         onIs = 1; 
         drawPic(g, offImage);
      }
      else if (onButt && !clickbutton) {
         onIs = 2; 
         drawButton(g);
         drawPic(g, onImage);
      }
      else {
         onIs = 3; 
         drawButton(g);
         drawPic(g, onImage);
      }
   }
}