/*

* Copyright (c) 2007-2008 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:    Music control observer interface 

*

*/

#ifndef __MSHWMUSICOBSERVER_H__

#define __MSHWMUSICOBSERVER_H__

#include <e32std.h>

/*! 

  @class MShwMusicObserver

  @discussion Observes for changes in the music controls volume and on/off state

              MPX-specific

  */

class MShwMusicObserver

    {

    public:

        /**

         * Notification that music is playing.

         * If this method leaves, MusicOff will

         * be called.

         */

        virtual void MusicOnL() = 0;

        /**

         * Notification that music is not playing

         */

        virtual void MusicOff() = 0;

        /**

         * Notification that music volume has changed

         * @param aCurrentVolume The current volume 

         * @param aCurrentVolume The maximum volume 

         */

        virtual void MusicVolumeL( TInt aCurrentVolume, TInt aMaxVolume ) = 0;

        /**

         * Notification that music track had an error

         * @param aErrorCode The error code

         */

        virtual void ErrorWithTrackL( TInt aErrorCode ) = 0;

    protected:

        /** 

         * Destructor. No deletion through this interface.

         */

        virtual ~MShwMusicObserver() {};

    };

#endif // __MSHWMUSICOBSERVER_H__