/*

* Copyright (c) 2005-2008 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: 

*             Declaration of class CMMKeyBearerObserver

*   

*

*/

#ifndef __MMKEYBEAREROBSERVERPS_H__

#define __MMKEYBEAREROBSERVERPS_H__

// INCLUDE

#include <e32svr.h>

#include <e32property.h>

// DATA TYPES

enum TObserverKeyType

{

    ESideVolumeKeys = 0,

    EMediaKeys,

    EAccessoryVolumeKeys,

    EFileTransferStatus

};

// CLASS DECLARATION

/**

*  MCallBackReceiver

*     Used to call functions of CMMKeyBearer from CMMKeyBearerObserver

*     On receiving event from the P & S, CMMKeyBearerObserver calls 

*     this function

*  @lib MMKeyBearer.dll

*  @since 3.0

*/

class MCallBackReceiver

    {

public:

    /**

    Called when event has arrived from P&S.

    @param aEnumValue: Enum value representing the key and action.

           aKeyType : will indicate whether it is Volume key or Media key

    */

    virtual void ReceivedKeyEvent(TInt aEnumValue, TInt aKeyType) = 0;

    };

/**

*  CMMKeyBearerObserver

*     This class inplements the Active Object. There will be two instance 

*     of this ,one for handling Volume keys and other for Media Keys

*  @lib MMKeyBearer.dll

*  @since 3.0

*/

class CMMKeyBearerObserver: public CActive

    {

    public: // Constructors and destructor

        /**

        * Creates instance of the CMMKeyBearerObserver class.

        * @param aCallBack : reference of the class which implements 

        *                    MCallBackReceiver for handling call back 

        *                    functions

        * @param aKeyType : Indiacates whether it is side volume key or 

        *                   media key

        * @return - Instance of the CMMKeyBearerObserver class.

        */

        static CMMKeyBearerObserver* NewL(MCallBackReceiver& aCallback, 

                                          TInt aKeyType);

        /**

        * Destructor.

        */

        virtual ~CMMKeyBearerObserver();    

    public: // Base class functions - CActive

        /** @see CActive::Start() */

        TInt Start();

        /** @see CActive::Stop() */

        void Stop();

       /**

        * Gets the current value.

        * @return - The current value.

        */

        TInt GetValue();

    private: // constructors

        /**

        * default constructor.

        * @param aCallback : reference to callback class

        */

        CMMKeyBearerObserver(MCallBackReceiver& aCallback);

        /**

        * Two - phase construction.

        */

        void ConstructL(TInt aKeyType);

    private: // Base class functions - CActive    

        /** @see CActive::RunL() */

        void RunL();

        /** @see CActive::DoCancel() */

        void DoCancel();

    private: // Data

        RProperty            iProperty;  // For P & S

        MCallBackReceiver&   iCallback;

        TInt                 iKeyType;   // Vol key or media Key

    };

#endif // __MMKEYBEAREROBSERVERPS_H__

// End of file