1 /*

     2 * Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

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

     6 * which accompanies this distribution, and is available

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

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:     

    15 *

    16 */

    17 

    18 

    19 #ifndef HGSCROLLBUFFEROBSERVERIFACE_H_

    20 #define HGSCROLLBUFFEROBSERVERIFACE_H_

    21 

    22 #include <e32base.h>

    23 #include <ganes/HgBufferOwnerIface.h>

    24 

    25 /**

    26  * Buffer observer interface. 

    27  */

    28 class MHgScrollBufferObserver : public MHgBufferOwner 

    29     {

    30 public:

    31     /**

    32      * The direction of request.

    33      */

    34     enum THgScrollDirection

    35         {

    36         EHgBufferNoMove, // Request initiated by adding or removing an item 

    37         EHgBufferReset, // Full buffer reset

    38         EHgBufferScrollUp, // Request items before the buffer

    39         EHgBufferScrollDown // Request items after the buffer

    40         };

    41 

    42 public:

    43     /**

    44      * Buffer position changed. 

    45      * The items between the aBufferStart and aBufferEnd should be loaded as soon as possible.

    46      * 

    47      * @param aBufferStart The index of the first item in buffer.

    48      * @param aBufferEnd The index of the last item in buffer.

    49      * @param aDirection Scroll direction.

    50      */

    51     virtual void Request(TInt aRequestStart, TInt aRequestEnd, THgScrollDirection aDirection) = 0 ;

    52     

    53     };

    54 

    55 #endif // HGSCROLLBUFFEROBSERVERIFACE_H_