1 /*

     2 * Copyright (c) 2002 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 CPROPERTYOBSERVER_H

    20 #define CPROPERTYOBSERVER_H

    21 

    22 // INCLUDES

    23 #include <e32base.h>

    24 #include <e32property.h>

    25 

    26 // CLASS DECLARATION

    27 

    28 /**

    29  * MPropertyChangeHandler.

    30  * Abstract interface for handling property change events.

    31  **/

    32 NONSHARABLE_CLASS( MPropertyChangeHandler )

    33 {

    34  public:

    35     /**

    36      * This is a callback function which is called when a property is changed.

    37      *

    38      * @param aCategory  UID of the category.

    39      * @param aKey       changed key

    40      * @param aValue     the new value

    41      *

    42      * Note! references aKey and aValue are only valid while executing

    43      * HandlePropertyChange(). After that the data in which they refer can change.

    44      **/

    45     virtual void HandlePropertyChange(const TUid& aCategory, const TUint& aKey, const TInt& aValue) = 0;

    46 

    47 };

    48 

    49 

    50 // CLASS DECLARATION

    51 

    52 /**

    53  * ?one_line_short_description.

    54  * ?other_description_lines

    55  *

    56  * @since Series 60 3.0

    57  **/

    58 NONSHARABLE_CLASS(CPropertyObserver) : public CActive

    59 {

    60  public:  // Constructors and destructor

    61     /**

    62      * Two-phased constructor.

    63      * @since Series 60 3.0

    64      * @param ?arg1 ?description

    65      * @param ?arg2 ?description

    66      **/

    67     static CPropertyObserver* NewL(MPropertyChangeHandler& aHandler, const TUid& aCategory, const TUint& aKey, const TBool aSkipValue=EFalse)

    68     {

    69         CPropertyObserver* self = new( ELeave )CPropertyObserver( aHandler, aCategory, aKey, aSkipValue );

    70         CleanupStack::PushL( self );

    71         self->ConstructL();

    72         CleanupStack::Pop( self );

    73         return self;

    74     };

    75 

    76     /**

    77      * Destructor.

    78      **/

    79     ~CPropertyObserver()

    80     {

    81         Deque();

    82         iProperty.Cancel();

    83         iProperty.Close();

    84     };

    85 

    86  private:

    87     /**

    88      * C++ default constructor overload.

    89      **/

    90     CPropertyObserver(MPropertyChangeHandler& aHandler, const TUid& aCategory, const TUint& aKey, const TBool aSkipValue)

    91     : CActive( CActive::EPriorityStandard ),

    92       iCategory( aCategory ),

    93       iKey( aKey ),

    94       iHandler( aHandler ),

    95       iSkipValue( aSkipValue )

    96     {

    97     };

    98 

    99     /**

   100      * By default Symbian 2nd phase constructor is private.

   101      **/

   102     void ConstructL(void)

   103     {

   104         CActiveScheduler::Add( this );

   105 

   106         User::LeaveIfError( iProperty.Attach( iCategory, iKey ) );

   107 

   108         //NotifyCurrentValue(); // notify initial value

   109 

   110         // Start observing...

   111         Subscribe();

   112     };

   113 

   114  protected:  // Functions from base classes

   115     /**

   116      * From CActive ?member_description

   117      **/

   118     inline void RunL(void);

   119 

   120     /**

   121      * From CActive ?member_description

   122      **/

   123     inline void DoCancel(void);

   124 

   125  private:  // New functions

   126     /**

   127      * ?member_description.

   128      * @since Series 60 3.0

   129      **/

   130     inline void Subscribe(void);

   131 

   132     /**

   133      * ?member_description.

   134      * @since Series 60 3.0

   135      **/

   136     inline void NotifyCurrentValue(void);

   137 

   138  private:  // Data

   139     // ?one_line_short_description_of_data

   140     RProperty iProperty;

   141 

   142     // ?one_line_short_description_of_data

   143     const TUid iCategory;

   144 

   145     // ?one_line_short_description_of_data

   146     const TUint iKey;

   147 

   148     // ?one_line_short_description_of_data

   149     MPropertyChangeHandler& iHandler;

   150 

   151     // ?one_line_short_description_of_data

   152     const TBool iSkipValue;

   153 

   154 };

   155 

   156 #include "PropertyObserver.inl"

   157 

   158 #endif  // CPROPERTYOBSERVER_H

   159 

   160 

   161 // End of File