If you are looking to create a music layer in android , here is the simple code snippet that can help you for this :-

Step 1:- Create an xml file for music player say"music_player.xml"

  <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
        android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        android:paddingBottom="@dimen/activity_vertical_margin"
        tools:context="com.africantunes.MediaPlayer.MusicPlayerTwo">
       <ImageView
          android:id="@+id/song_image"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:layout_alignParentTop="true"
          android:scaleType="centerInside"
          android:background="@drawable/playon"
          android:layout_above="@+id/controls_layout"/>
       <LinearLayout
          android:layout_alignParentBottom="true"
          android:layout_width="fill_parent"
          android:layout_height="wrap_content"
          android:layout_gravity="center_horizontal"
          android:background="@drawable/rounded_corner"
          android:gravity="center"
          android:orientation="horizontal"
          android:padding="@dimen/padding_10dp"
          android:id="@+id/controls_layout">
           <ImageButton
             android:id="@+id/btnPrevious"
           android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginLeft="@dimen/padding_10dp"
             android:layout_marginRight="@dimen/padding_10dp"
             android:background="@null"
             android:src="@drawable/icon_back" />
           <ImageButton
             android:id="@+id/btnPlay"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginLeft="@dimen/padding_10dp"
             android:layout_marginRight="@dimen/padding_10dp"
             android:background="@null"
             android:src="@drawable/pause_green" />
          <ImageButton
             android:id="@+id/btnNext"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginLeft="@dimen/padding_10dp"
             android:background="@null"
             android:src="@drawable/icon_next" />
         </LinearLayout>
   </RelativeLayout>

Step 2:- create certain functions on your main Activity :-

(a):- function to initialize widgets

  private void initialisingWidgets()
    {
     songLoadingBar = (ProgressBar) findViewById(R.id.song_loading_progress);
     btnPlay = (ImageButton) findViewById(R.id.btnPlay);
     btnNext = (ImageButton) findViewById(R.id.btnNext);
     btnPrevious = (ImageButton) findViewById(R.id.btnPrevious);

 btnPlay.setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View arg0) {
      if (mp.isPlaying()) {
         if (mp != null) {
               mp.pause();
               btnPlay.setImageResource(R.drawable.play_green);
          }
       } 
     else {
        if (mp != null) {
           mp.start();
           btnPlay.setImageResource(R.drawable.player_pause);
         }
      }
  }});


  btnNext.setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View arg0) {
    if (currentSongIndex < (songsList.size() - 1)){
       currentSongIndex = currentSongIndex + 1;
     } 
    else{
     currentSongIndex = 0;
     }
   initializeMediaPlayer();
   playSongAsynctask = new PlaySongAsynctask( currentSongIndex);
   playSongAsynctask.execute();
   } });


  btnPrevious.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View arg0) {
     if (currentSongIndex > 0){
       currentSongIndex = currentSongIndex - 1;
      }
     else{
       currentSongIndex = songsList.size() - 1;
      }
    initializeMediaPlayer();
    playSongAsynctask = new PlaySongAsynctask( currentSongIndex);
    playSongAsynctask.execute();
    }});
}

(b):- Initialize media player:-

public void initializeMediaPlayer()
     {
       if (mp != null){
           mp.stop();
           mp.release();
           mp = null;
           mp = new MediaPlayer();
        }
       else{
      mp = new MediaPlayer();
    }

    mp.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
    @Override
    public void onCompletion(MediaPlayer mp){
        mp.stop();
        mp.release();
        mp = null;
        if (currentSongIndex < (songsList.size() - 1)){
          if (!isErrorInUri) {
            currentSongIndex = currentSongIndex + 1;
           }
           else{
              if (!isErrorInUri) {currentSongIndex = 0};
           }
         } 
         playSongAsynctask = new PlaySongAsynctask( currentSongIndex);
         playSongAsynctask.execute();
     }});
  }

(c):- Prepare the mediaPlayer, in background and play song:-

  private class PlaySongAsynctask extends AsyncTask<Void, String, Void> 
     {
   String url;

   public PlaySongAsynctask( int songIndex) 
    {
        initializeMediaPlayer();
        url = songsList.get(songIndex);
    }

    @Override
    protected void onPreExecute() {
     super.onPreExecute();
     songLoadingBar.setVisibility(View.VISIBLE);
    }


    @Override
    protected Void doInBackground(Void... params) {
     try 
      {
        isErrorInUri = false;
        mp.setDataSource(MusicPlayerTwo.this, Uri.parse(url));
        mp.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mp.setOnPreparedListener(new MediaPlayer.OnPreparedListener(){
           @Override
           public void onPrepared(MediaPlayer mp) {
           songLoadingBar.setVisibility(View.GONE);
           mp.start();} });
        mp.prepare();
      } 
     catch (FileNotFoundException e) 
      {
        System.out.println("Exception" + e);
        e.printStackTrace();
        runOnUiThread(new Runnable() {
           @Override
            public void run() {
              dialog = MyUtility.errorMessageAlert(MusicPlayer.this, getResources().getString(R.string.uri_exception_msg));}
        }});
      } 
    return null;
 }

Step 3:- Integrate all the function created on step 2 into OnCreate() method of your activity.

 setContentView(R.layout.music_player);
 initializeMediaPlayer();
 initialisingWidgets();
 initializeMediaPlayer();
   for(int i=0;i<5;i++)
     {
       songsList.add("http://...........song1.mp4");
     }
 playSongAsynctask = new PlaySongAsynctask(currentSongIndex);
 playSongAsynctask.execute();