Learning Java - Chapter 12 : Java

In the early versions of Java the audio capabilities in the core language were extremely limited. Only 8 kHz au type files could be played.

With version 1.2, it became possible to play 22KHz, 16-bit stereo in the following formats:

However, these advanced audio capabilities are beyond the scope here. We will only look at the simply playing of sound clips.

While audio may have limited applications for scientific programs, they can be useful for such things as warnings and alarms.

The following applet shows the basics of playing a sound clip. The loop() method will continously repeat the clip.

AudioTestApplet.java

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

/** Demonstrate playing an audio clip. **/
public class AudioTestApplet extends JApplet
{
  public void init () {
    Container content_pane = getContentPane ();
    // Create an instance of a JPanel sub-class
    AudioPanel audio_panel =
       new AudioPanel (getClip (false));
    // And add one or more panels to the JApplet panel.
    content_pane.add (audio_panel);
  } // init

  AudioClip getClip (boolean FileInJar) {
    if (FileInJar) {
        // Use getResource () to search directory or a jar file.
        return (getAudioClip (
                getClass ().getResource (getParameter ("AudioClip")))
             );

    } else {
        // Read  audio file from the code directory
        return (getAudioClip (getCodeBase (),
                              getParameter ("AudioClip")) );
    }
  } // getClip

} // class AudioTestApplet

/** This panel holds a button to play/stop a clip in loop mode.**/
class AudioPanel extends JPanel
                   implements ActionListener
{
  AudioClip fAudioClip = null;
  JButton fButton = null;
  boolean fPlay = false;

  /** Constructor gets the clip and makes a button for the panel.**/
  AudioPanel (AudioClip audioClip) {
    fAudioClip = audioClip;
    // Add a button for the interface.
    fButton =  new JButton ("Play Clip" );
    fButton.addActionListener (this);
    add (fButton);
  } // ctor

  /** Button will start/stop the clip playing.**/
  public void actionPerformed (ActionEvent e ) {
    if (fAudioClip  != null) {
        if (!fPlay) {
            fButton.setText("Stop clip");
            fAudioClip.loop ();
            fPlay = true;
        } else {
            fButton.setText("Play clip");
            fAudioClip.stop();
            fPlay = false;
        }
    }
  } // actionPerformed

} // class AudioPanel