title: MediaPlayer's SetOnCompletionListener is not working
body: <p>m using service to play a audio file in background.</p>
  
  <p>This is my PreviewServices class .</p>
  
  <pre><code>package com.hungama.myplay.activity;
  import java.io.IOException;
  import android.app.Service;
  import android.content.Intent;
  import android.media.MediaPlayer;
  import android.media.MediaPlayer.OnBufferingUpdateListener;
  import android.media.MediaPlayer.OnCompletionListener;
  import android.net.Uri;
  import android.os.Binder;
  import android.os.Bundle;
  import android.os.IBinder;
  import android.util.Log;
  import android.widget.MediaController;
  import android.widget.Toast;
  
  public class PreviewServices extends Service {
   private static final String TAG = "PreviewServices";
   public static MediaPlayer player;
   protected DataManager dataManager = DataManager.getInstance();
   String song_uri, url;
   private IBinder myBinder;
   private boolean isplaying;
  
   @Override
   public IBinder onBind(Intent intent) {
    return null;
   }
  
   public class MyBinder extends Binder {
    PreviewServices getService() {
     return PreviewServices.this;
    }
   }
  
   @Override
   public void onCreate() {
    Log.d(TAG, "onCreate " + song_uri);
  
   }
  
   @Override
   public void onDestroy() {
   player.stop();
  
   }
  
   public void onPause() {
  
    player.pause();
   }
  
   public double duration() {
    return player.getDuration();
   }
  
   public void onStart(Intent intent, int startid) {
     Bundle b = intent.getExtras();
    song_uri = b.getString("song_uri");
     Uri path = Uri.parse(song_uri);
  
    player = MediaPlayer.create(this, path);
  
    player.setLooping(false); // Set looping
     player.start();
  / *player.setOnCompletionListener(new OnCompletionListener() {
  
   public void onCompletion(MediaPlayer mp) {
    // TODO Auto-generated method stub
   Log.d("song is completed","song is not playing now");
   dataManager.setPreview_play(true);
  
   }
  });
  */ 
  
   }
  }
  
  My PreviewServices is working fine, 
  
  in My Activity i want to show a message when my song will complete.
  
  m using this code for this purpose.
  
      PreviewServices preview=new PreviewServices();
  
  
  
  
  MusicScreen.this.preview.player.setOnCompletionListener(new OnCompletionListener() {
  
  
  
  public void onCompletion(MediaPlayer mp) {
  
  // TODO Auto-generated method stub
  
          Log.d("song is complete","song complete");
  
                      }
  
                  });
  </code></pre>
  
  <p>I dont know Y its throws Null Pointer Exception in this line</p>
  
  <p>MusicScreen.this.preview.player.setOnCompletionListener(new OnCompletionListener()</p>
  
  <p>please suggest  me where is problem.</p>
  
  <p>thanks in advance.</p>
  
  <p>Gaurav Gupta</p>