simtoolbar.java

模拟工作条用URL显示 鼠标电击事件的显示

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

public class SimToolBar extends Applet implements MouseListener{

   private  MediaTracker myTracker;
  
   private  Image enterImage, exitImage;
   private  boolean onButton = false;
   private  boolean clickButton = false;
   private  int onImages = 0;
   private  URL myURL;
   private  String target, myString, where;

   public void init(){
      
      if ((myString = getParameter("where")) != null)
         where = myString;
      else
         where = null;

      myTracker = new MediaTracker(this);
      enterImage  = getImage(getDocumentBase(), getParameter("enterImage"));
      myTracker.addImage(enterImage, 0);
      exitImage = getImage(getDocumentBase(), getParameter("exitImage"));
      myTracker.addImage(exitImage, 0);
      
      try {
         myTracker.waitForAll();
      } catch (InterruptedException e) {}
             
      target = getParameter("target");
      try{
         myURL = new URL(getDocumentBase(), target);
         System.out.println(target);
      }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 && onButton){
         clickButton = false;
         repaint();
      
         if (where != null)
            getAppletContext().showDocument(myURL, where);
         else 
            getAppletContext().showDocument(myURL);
      }else{
   
         clickButton = false;
         repaint();
      }
    
   }
   
   public void mouseEntered(MouseEvent e){
       onButton = true;
       repaint();    
   }
   
   public void mouseExited(MouseEvent e){
   
    onButton = false;
    repaint();
    
   }
   
   public void drawImg(Graphics g, Image theImage){
      int a; 
      if (onImages == 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 (onImages == 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(!onButton){
         onImages = 1; 
         drawImg(g, exitImage);
      }
      else if (onButton && !clickButton) {
         onImages = 2; 
         drawButton(g);
         drawImg(g, enterImage);
      }
      else {
         onImages = 3; 
         drawButton(g);
         drawImg(g, enterImage);
      }
   }
}