Reproduce archivos MP3 desde android

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/tvMsg"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/app_name"
        android:gravity="center"
        android:textSize="32sp" />

    <Button
        android:id="@+id/btnPlay"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/str_play" />

    <Button
        android:id="@+id/btnPause"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/str_pause" />

    <Button
        android:id="@+id/btnStop"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/str_stop" />

    <TextView
        android:id="@+id/tvTime"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/app_name"  
        android:textSize="18sp" />    

    <SeekBar
        android:id="@+id/skSong"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

    <string name="str_play">PLAY</string>
    <string name="str_pause">PAUSE</string>
    <string name="str_stop">STOP</string>

package com.bolivia.jmplayer;

import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.TextView;

public class MainActivity extends Activity{

 private TextView tvMsg;
 private Button btnPlay;
 private Button btnPause;
 private Button btnStop;
 private SeekBar skSong;
 private TextView tvTime;
 private MediaPlayer mPlayer = null; 
 private Handler skHandler = new Handler();

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  //-- begin 
  mPlayer = MediaPlayer.create(MainActivity.this, R.raw.onnanokootokonoko);  

  tvMsg = (TextView) findViewById(R.id.tvMsg);
  btnPlay = (Button) findViewById(R.id.btnPlay);
  btnPause = (Button) findViewById(R.id.btnPause);
  btnStop = (Button) findViewById(R.id.btnStop);
  skSong = (SeekBar) findViewById(R.id.skSong);  
  tvTime = (TextView) findViewById(R.id.tvTime);

  //----------- button PLAY 
  btnPlay.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View view) {

           if(!mPlayer.isPlaying())
           {
            mPlayer.start();
            tvMsg.setText("PLAY");
           }           
          }
      });
  //----------- button PAUSE
  btnPause.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View view) {

          if(mPlayer.isPlaying())
          {
           mPlayer.pause();
           tvMsg.setText("PAUSE");
          }           
         }
     });

  //----------- button STOP 
  btnStop.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View view) {           
           if (mPlayer != null) {
                  mPlayer.stop();
                  mPlayer.release();
                  mPlayer = MediaPlayer.create(MainActivity.this, R.raw.onnanokootokonoko);
                  tvMsg.setText(":)");
                }           
         }
     });    

  //--- Se coloca el tiempo de duracion y se inicia el seek bar
  tvTime.setText( getHRM(mPlayer.getDuration()) );
  skSong.setMax(mPlayer.getDuration());
  skSong.setProgress(mPlayer.getCurrentPosition());
  //cada segundo se actualiza el estado del seek bar
  skHandler.postDelayed(updateskSong, 1000); 

  //-- end
 }//end:onCreate

 //se hace uso de un hilo para actualizar el progreso de la reproducción 
 Runnable updateskSong = new Runnable() { 
  @Override 
  public void run() {
   skSong.setProgress( mPlayer.getCurrentPosition() );
   tvTime.setText( getHRM(mPlayer.getDuration()) + " - " + getHRM(mPlayer.getCurrentPosition()) );
   skHandler.postDelayed(updateskSong, 1000); 
  } 
 };

 /**
 * Método que convierte milisegundos a Hora:Minuto:Segundo
 * @param int milliseconds
 * @return String HH:MM:SS
 * */
 private String getHRM(int milliseconds )
 {
  int seconds = (int) (milliseconds / 1000) % 60 ;
  int minutes = (int) ((milliseconds / (1000*60)) % 60);
  int hours   = (int) ((milliseconds / (1000*60*60)) % 24);
  return ((hours<10)?"0"+hours:hours) + ":" + 
         ((minutes<10)?"0"+minutes:minutes) + ":" + 
         ((seconds<10)?"0"+seconds:seconds);
 }

 /** 
 * Cuando la actividad ya no es visible por el usuario,
 * se detiene el reproductor
 * */
 @Override
 protected void onStop() {
  super.onStop();
        if (mPlayer != null) {
         mPlayer.stop();
         mPlayer.release();
         mPlayer = MediaPlayer.create(MainActivity.this, R.raw.onnanokootokonoko);
       }
    }

 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
  getMenuInflater().inflate(R.menu.main, menu);
  return true;
 }

}