1 /*

     2 * Copyright (c) 2007 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:   Event handler API

    15 *

    16 */

    17 

    18 

    19  

    20 #ifndef ALFEVENTHANDLER_H

    21 #define ALFEVENTHANDLER_H

    22 

    23 #include <e32base.h>

    24 

    25 class TAlfEvent;

    26 

    27 /**

    28  * MAlfEventHandler is an interface that can be derived by any object that want's to handle

    29  * Alfred UI Toolkit events scheduled by AlfCommandScheduler.

    30  * 

    31  * If an object wishes to process events from the toolkit, it should implement this interface. 

    32  * 

    33  * @note   The destructor will NOT cancel any pending commands enqueued to this object,

    34  *         so you must call eg. <code>CAlfEnv::CancelCommands(this);</code> to cancel

    35  *         still pending commands to prevent calling destroyed object.

    36  */

    37 class MAlfEventHandler

    38     {

    39 public:

    40 

    41     /**

    42      * Called when an input event is being offered to this object.

    43      * 

    44      * The implementation must ensure that the function returns EFalse if 

    45      * it does not do anything in response to the event, otherwise, other objects

    46      * may be prevented from receiving the event. If it is able to process the 

    47      * event it should return ETrue.

    48      *

    49      * @param aEvent  Event to be handled.

    50      *

    51      * @return  <code>ETrue</code>, if the event was handled.

    52      *          Otherwise <code>EFalse</code>.

    53      */

    54     virtual TBool OfferEventL(const TAlfEvent& aEvent) = 0;

    55 

    56     };  

    57 

    58 #endif  // ALFEVENTHANDLER_H