Android MediaPlayer Singleton

Question

I have read several of the articles on here that suggest using the singleton code, Which I have read and placed into the soundboard as I want to use the singleton code to only allow one mediaplayer instance no matter how many clicks the user defines.

Basically I only want one sound and if the user clicks another button during playback it stops the current sound and plays the one that is pressed. I want only the one MediaPlayer instance but do not understand how to implement it.

Here is the basic idea of my code:

    package com.example.context;

    import java.io.File;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;




    import android.app.Activity;
    import android.content.ContentValues;
    import android.content.Intent;
    import android.media.MediaPlayer;
    import android.net.Uri;
    import android.os.Bundle;
    import android.provider.MediaStore;
    import android.view.ContextMenu;
    import android.view.MenuItem;
    import android.view.View;
    import android.view.ContextMenu.ContextMenuInfo;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.Toast;

    public class main extends Activity implements OnClickListener {

    MediaPlayer player;

    int[] ressound ={R.raw.boomstick, R.raw.chainsaw, R.raw.shebitch, R.raw.byebye,
    R.raw.comegetsome, R.raw.groovy, R.raw.shoelace, R.raw.smart,   R.raw.yeahbaby};//added as needed
    int j=0;
    private static final String TAG = "MyTag";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);


     //Coding for all buttons, registers, and Listeners
        Button btn1 = (Button) findViewById(R.id.btn1);
        registerForContextMenu(btn1); 
        btn1.setOnClickListener(this);
        Button btn2 = (Button) findViewById(R.id.btn2);
        registerForContextMenu(btn2);
        btn2.setOnClickListener(this);
        Button btn3 = (Button) findViewById(R.id.btn3);
        registerForContextMenu(btn3);
        btn3.setOnClickListener(this);

    }

     //On click Handlers for multiple buttons 
        public void onClick(View v) {
        switch(v.getId()){
        case R.id.btn1:
        // action to perform on button 1
        j = 0;
        playResource();
        break;
    case R.id.btn2:
        // action to perform on button 1
        j = 1;
        playResource();
        break;
    case R.id.btn3:
        // action to perform on button 1    
        j = 2;
        playResource();
        break;

    }
         public void playResource(int j, int resource) {
    this.j = j;
    if (player != null) {
        if (player.isPlaying())
            player.stop();
        player.reset();
        //from MediaPlayer implementation (link above)
        try {
            AssetFileDescriptor afd = getResources().openRawResourceFd(resource);
            if (afd == null) return;
            player.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getLength());
            afd.close();
            player.prepare();
        } catch (IOException ex) {
            Log.d(TAG, "create failed:", ex);
            // failed: return
        } catch (IllegalArgumentException ex) {
            Log.d(TAG, "create failed:", ex);
            // failed: return
        } catch (SecurityException ex) {
            Log.d(TAG, "create failed:", ex);
            // failed: return
        }
    }
    else {
        //player is null
        //it will create new MediaPlayer instance, setDataSource and call prepare
        player = MediaPlayer.create(this, resource);
    }
    //if everything ok play file
    //in case of any error return from method before (catch)
    player.start();
}

This is what I had to update and change my code too but it is giving me a problem with passing the playresource() function. Am I passing it wrong, should it be private that is passing.

Answer 1

You don't need a Singleton for that. What are you doing is calling create method every time you want to play a file. That's wrong because you already have MediaPlayer instance. Check MediaPlayer.create implementation. I would do like that:

• create new method playResource(int j, int resource)
• in every case R.id.btnX i would call method playResource(X, R.raw.Y) - X and Y depends on btn

playResource method example:

private static final String TAG = "MyTag";
playResource(int j, int resource) {
    this.j = j;
    if (player != null) {
        if (player.isPlaying())
            player.stop();
        player.reset();
        //from MediaPlayer implementation (link above)
        try {
            AssetFileDescriptor afd = getResources().openRawResourceFd(resource);
            if (afd == null) return null;
            player.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getLength());
            afd.close();
            player.prepare();
        } catch (IOException ex) {
            Log.d(TAG, "create failed:", ex);
            // failed: return
        } catch (IllegalArgumentException ex) {
            Log.d(TAG, "create failed:", ex);
            // failed: return
        } catch (SecurityException ex) {
            Log.d(TAG, "create failed:", ex);
            // failed: return
        }
    }
    else {
        //player is null
        //it will create new MediaPlayer instance, setDataSource and call prepare
        player = MediaPlayer.create(this, resource);
    }
    //if everything ok play file
    //in case of any error return from method before (catch)
    player.start();
}

When you don't need MediaPlayer again, you should release it. For example in onPause() call:

if (player != null) {
    player.release();
    player = null;
} 

I didn't test that so there could be errors. Hope it helps.

Answer 2

The getSingletonObject() method should return an instance of MediaPlayer, created using the default constructor for MediaPlayer (without specifying the resource).

You could call getSingletonObject() from onCreate() in the main class and initialize the player with it.

Later in the onClick(), you should call, player.prepare() and then player.setDataSource(), passing in the resource.

So, your code should look something like the below:

   public static MediaPlayer getSingletonObject()
  {
    if (ref == null)
        // it's ok, we can call this constructor
        ref = new MediaPlayer();        
    return ref;
  }

In the main class, in the onCreate() method,

public void onCreate(Bundle savedInstanceState) {
//....
//....
player=SingletonObject.getSingletonObject();
}

Hope you can figure out the code in onClick() by yourself. And don't forget to add the appropriate try..catch clauses in the onClick() method.

Hope this helps!!

Answer 3

I have been trying to solve this issue for a project of myself. I ran in the same issue that while playing a second playback will let the app crash.

Adding player = new MediaPlayer(); solved the issue (seems no mediaplayer was initiated in the try-catch block).

See the code below:

    playResource(int j, int resource) {
this.j = j;
if (player != null) {
    if (player.isPlaying())
        player.stop();
    player.reset();

    try {
        player = new MediaPlayer(); //added to the code
        AssetFileDescriptor afd = getResources().openRawResourceFd(resource);
        if (afd == null) return null;
        player.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getLength());
        afd.close();
        player.prepare();
    } catch (IOException ex) {
        Log.d(TAG, "create failed:", ex);
        // failed: return
    } catch (IllegalArgumentException ex) {
        Log.d(TAG, "create failed:", ex);
        // failed: return
    } catch (SecurityException ex) {
        Log.d(TAG, "create failed:", ex);
        // failed: return
    }
}
else {
    //player is null
    //it will create new MediaPlayer instance, setDataSource and call prepare
    player = MediaPlayer.create(this, resource);
}