example8_15.java

书中的例题

import java.applet.*;
import java.awt.*;
import java.net.*;
import java.awt.event.*;
import java.io.*;
import javax.media.*;
public class Example8_15 extends Applet
 implements ControllerListener,ActionListener 
{  Player player;
   String str; 
   Component visualComponent,controlComponent;
   String mediaFile;
   URL mediaURL,codeBase;
   Frame frame;
   Button btn;

   public void init()
   {
	 str="music01.mpg"; 
	 //str="df.mp3";
	 btn=new Button("play");
     codeBase=getDocumentBase();
     add(btn);
	 btn.addActionListener(this);
   } 

 public void actionPerformed(ActionEvent e)
   { 
	 frame=new Frame("视频系统");
     frame.setSize(60,50);
     frame.addWindowListener(new WindowAdapter()
            {  public void windowClosing(WindowEvent e)
               {  if(player!=null)
                    {
		              player.stop();
	                  player.deallocate(); 
					  player.close();
                    }
                 frame.setVisible(false);
                 frame.dispose();
               } 
            });
      frame.removeAll();
      frame.setVisible(true);
      frame.setBounds(300,100,350,300);
      frame.validate();
	  play();
   }

   public synchronized void controllerUpdate(ControllerEvent event)
   {
	 player.getDuration();
     if(event  instanceof  RealizeCompleteEvent)
        { if((visualComponent=player.getVisualComponent())!=null)
                 frame.add("Center",visualComponent);
          if((controlComponent=player.getControlPanelComponent())!=null)
                 frame.add("South",controlComponent);
          frame.validate();
          frame.pack();
        }
     else if(event  instanceof  PrefetchCompleteEvent)
       { 
		 player.start(); 
       }
   }

 public void play()
   { 
	 try{ 
	      mediaURL=new URL(codeBase,str);
          player=Manager.createPlayer(mediaURL);
		  player.getDuration();
		  player.addControllerListener(this);

         }
       catch(MalformedURLException e)
         {  System.out.println("URL for"+mediaFile+"is invalid");  }
       catch(IOException e)
         {  System.out.println("URL for"+mediaFile+"is invalid");  }
       catch(NoPlayerException e)
         { System.out.println("canot find a player for"+mediaURL); }
       if(player!=null)
       {
		   player.prefetch(); 
       }
   }
 }