Smile2.java

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// <APPLET CODE="Smile2" WIDTH="320" HEIGHT="430">
//    <PARAM NAME="IMAGE" VALUE="Mona.gif">
//    <PARAM NAME="SOUND" VALUE="spacemusic.au">
// </APPLET>
// Smile2.java - A Java applet that displays a GIF graphic and plays music.
// Note: A non-applet can get an image easily by using:
//   Image pic = Toolkit.getDefaultToolkit().getImage( "Mona.gif" );
// but this usually won't work for applets.  (Also, applets have
// their own getImage method.)  One way to deal with images in applets
// is by using a MediaTacker object, shown here.  The only problem is
// to say where to find the graphic.  If it resides on the server,
// in the directory where the .class file resides, you can load the
// image as:
//     Image pic = getImage( getCodeBase(), imageName );
// (or you can use "getImage( getCodeBase(), "../images/" + imageName )" if
// the image is in a relative directory.  Note this doesn't work if the graphic
// (or other media) is in a jar file!  The method used here works with or
// without jar files.  (See "SmileJar.java" for a demo of jar files.)
//
// Final note: Applets that continuously play sounds are annoying!  You
// should always provide some way for the user to turn off the sound loop.
// A Checkbox menuItem or a small button (shown here) does the trick!
//
// Written 2000 by Wayne Pollock, Tampa FL USA.

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class Smile2 extends Applet implements ActionListener
{
   private String imageName, sndName;
   private Image pic = null;
   private int picWidth, picHeight;
   private AudioClip snd = null;
   private Button btn;  // Sound on/off button
   private boolean isPlaying = true;

   public void init ()
   {
      imageName = getParameter( "IMAGE" );
      sndName = getParameter( "SOUND" );

      if ( imageName != null )
      {   pic = getImage( getClass().getResource( imageName ) );
          showStatus( "Loading Media Files..." );  // Display msg in status bar.
          MediaTracker mt = new MediaTracker( this );
          mt.addImage( pic, 0 );
          try {
             mt.waitForAll();
          }
          catch ( InterruptedException ie ) {}
          if ( mt.isErrorAny() )
             pic = null;

          // Image is fully loaded when we get to here:
          picWidth = pic.getWidth( this );
          picHeight = pic.getHeight( this );
      }

      if ( sndName != null )  // Note: MediaTrackers only work on images.
         snd = getAudioClip( getClass().getResource( sndName ) );

      setBackground( Color.CYAN );
      setLayout( new BorderLayout() );
      btn = new Button( "Turn Sound Off" );
      btn.addActionListener( this );
      Panel p = new Panel();
      p.add( btn );
      add( p, "South" );
   }


   public void start ()
   {  if ( snd != null && isPlaying )  snd.loop();  }


   public void stop ()
   {  if ( snd != null ) snd.stop(); }


   public void actionPerformed ( ActionEvent e )
   {
      if ( snd == null ) return;
      if ( isPlaying )
      {  snd.stop();
         btn.setLabel( "Turn Sound On" );
      }
      else
      {  snd.loop();
         btn.setLabel( "Turn Sound Off" );
      }
      isPlaying = !isPlaying;
      this.requestFocus(); // remove focus from button, which I find ugly.
   }


   public void paint ( Graphics g )
   {
      if ( pic == null )
         g.drawString( "Error loading Image!", 10, 10 );
      else
      {
         g.setColor( Color.red );
         g.fillRect( 7, 7, picWidth+6, picHeight+6 );
         g.drawImage( pic, 10, 10, this );
      }
   }
}

Send comments and questions to pollock@acm.org.