Implementing the game sound

SoundEffects class

This class uses the MIDP 2.0 Media API to play four sound effects: a sheep's "baa," a dog's bark, and two short game-over MIDI tunes.

1. Create the SoundEffects class file

2. Import the required classes.

   // unnamed package
   import javax.microedition.media.*;
   import java.io.*;
   

3. Create the SoundEffects class. The Player class controls the rendering of time based media data. It provides the methods to manage the Player's life cycle, controls the playback progress and obtains the presentation components.

   For more informations, see Player in the MIDP 2.0 API specification.

   class SoundEffects
   {
       private static SoundEffects instance;
       private Player sheepSoundPlayer;
       private Player dogSoundPlayer;

4. Initialize the sound effects for the animal noises. The createPlayer method is detailed later in step 7.

       private SoundEffects()
       {
           sheepSoundPlayer = createPlayer("/sheep.wav", "audio/x-wav");
           dogSoundPlayer = createPlayer("/dog.wav", "audio/x-wav");
       }
   
       static SoundEffects getInstance()
       {
           if (instance == null)
           {
               instance = new SoundEffects();
           }
           return instance;
       }
   

5. Create methods for playing the sound effects.

       void startSheepSound()
       {
           startPlayer(sheepSoundPlayer);
       }
       
       void startDogSound()
       {
           startPlayer(dogSoundPlayer);
       }
   
       void startGameOverSound()
       {
           startPlayer(createPlayer("/gameover.mid", "audio/midi"));
       }
       
       void startHighScoreSound()
       {
           startPlayer(createPlayer("/highscore.mid", "audio/midi"));
       }
       

6. Create a method to control the playing of the sound effects detailed in step 5. The stop method stops the Player, start starts the Player as soon as possible and setMediaTime sets the Player's media time. A MediaException indicates an unexpected error condition in a method.

   For more information, see stop, start, setMediaTime and MediaException in the MIDP 2.0 API specification.

       private void startPlayer(Player p)
       {
           if (p != null)
           {
               try
               {
                   p.stop();
                   p.setMediaTime(0L);
                   p.start();
               }
               catch (MediaException me)
               {
                   // ignore
               }
           }
       }

7. Create a method for fetching the individual sounds from external files. Manager is the access point for obtaining system dependent resources such as Players for multimedia processing. The createPlayer method creates a Player to play back media from an InputStream whereas the prefetch method acquires the scarce and exclusive resources and processes as much data as necessary to reduce the start latency.

   For more information, see Manager, createPlayer, prefetch in and the MIDP 2.0 API specification.

       private Player createPlayer(String filename, String format)
       {
           Player p = null;
           try
           {
               InputStream is = getClass().getResourceAsStream(filename);
               p = Manager.createPlayer(is, format);
               p.prefetch();
           }
           catch (IOException ioe)
           {
               // ignore
           }
           catch (MediaException me)
           {
               // ignore
           }
           return p;
       }
   }