ajout d'un pattern Singleton à mon activity

Bonjour,

je suis entrain de développer une application qui permet la lecture des audio (.mp3) (une liste : chaque item contient l'audio correspondant )

je veux ajouter un singleton (une seule instance à tous les urlaudio)
j'ai pas compris comment je peux l'ajouter voila mon activité qui permet la lecture de chaque audio
Code:
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package com.streamerz.podcast;
 
import java.util.ArrayList;
 
import android.app.Activity;
import android.content.res.AssetFileDescriptor;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
 
import com.streamerz.slideout.R;
 
 
 
public class lecture_audio_podcast extends Activity
{
	  private ItemStructure_pod reservationdata1 = new ItemStructure_pod();
  	static ArrayList<ItemStructure_pod> Content1 = new ArrayList<ItemStructure_pod>();
 
 
     String url_audio;
    private String title;
    private MediaPlayer mediaPlayer;
    private int playbackPosition=0;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    	Bundle b = getIntent().getExtras();
        ItemStructure_pod item_pod=XMLhandler_pod.channelList.get(b.getInt("title"));
 
        title = this.getIntent().getStringExtra("title");
 
        String ii=item_pod.getUrl();
     Log.i("ggggg","jjjjjjjjjjjjjjj"+ii);
       	    url_audio=ii;
 
    }
    protected void initSingletons()
	{
		// Initialize the instance of MySingleton
		MySingleton.initInstance();
	}
 
    public void customAppMethod()
	{
		// Custom application method
	}
 
    public void doClick(View view) {
        switch(view.getId()) {
        case R.id.startPlayerBtn:
            try {
            	// Only have one of these play methods uncommented
            	playAudio(url_audio);
//              playLocalAudio();
//              playLocalAudio_UsingDescriptor();
            } catch (Exception e) {
                e.printStackTrace();
            }
            break;
        case R.id.pausePlayerBtn:
            if(mediaPlayer != null && mediaPlayer.isPlaying()) {
                playbackPosition = mediaPlayer.getCurrentPosition();
                mediaPlayer.pause();
            }
            break;
        case R.id.restartPlayerBtn:
            if(mediaPlayer != null && !mediaPlayer.isPlaying()) {
                mediaPlayer.seekTo(playbackPosition);
                mediaPlayer.start();
            }
            break;
        case R.id.stopPlayerBtn:
            if(mediaPlayer != null) {
                mediaPlayer.stop();
                playbackPosition = 0;
            }
            break;
        }
    }
 
    private void playAudio(String url) throws Exception
    {
      killMediaPlayer();
 
        mediaPlayer = new MediaPlayer();
        mediaPlayer.setDataSource(url);
        mediaPlayer.prepare();
        mediaPlayer.start();
    }
 
    private void playLocalAudio() throws Exception
    {
        mediaPlayer = MediaPlayer.create(this, R.raw.music_file);
        mediaPlayer.start();
    }
 
    private void playLocalAudio_UsingDescriptor() throws Exception {
 
        AssetFileDescriptor fileDesc = getResources().openRawResourceFd(
        		R.raw.music_file);
        if (fileDesc != null) {
 
            mediaPlayer = new MediaPlayer();
            mediaPlayer.setDataSource(fileDesc.getFileDescriptor(), fileDesc
                    .getStartOffset(), fileDesc.getLength());
 
            fileDesc.close();
 
            mediaPlayer.prepare();
            mediaPlayer.start();
        }
    }
 
    @Override
    protected void onDestroy() {
        super.onDestroy();
       killMediaPlayer();
    }
 
   private void killMediaPlayer() {
        if(mediaPlayer!=null) {
            try {
                mediaPlayer.release();
            }
            catch(Exception e) {
                e.printStackTrace();
            }
        }    }
 
 
}
Merci d'avance.