Using Extended Notifiers

The Symbian notifier framework allow system or custom event to be handled quite easily by your application. It’s an easy way for a server with no UI to display some events on the phone screen.

The behaviour of notifiers is supplied by providing an implementation of the MEikSrvNotifierBase interface . A notifier is associated with a channel and a priority. Priority is used to determine the order of activation if more than one notifier is activated at any time. Priority only affects notifiers on the same channel (e.g. a screen or LED). This means that two notifiers can be active at the same time provided that they are on different channels.

Here is how you can define your own custom notifier:

1. Implement a class which inherits from both CEikDialog and MEikSrvNotifierBase.


#include "CknNtfy.h"
#include <eikdialg.h>
        
/**
* class CCknMmcNotifier
*
* a sleeping dialog used to request a password when a protected MMC is inserted
*/
class CCknMmcNotifier : public CEikDialog, public MEikSrvNotifierBase
        {
public:
        static CCknMmcNotifier* NewL();
        ~CCknMmcNotifier();
public:
        CCknMmcNotifier();
        void ConstructL();
        TInt DisplayNotifier();
// from CEikDialog
        void PreLayoutDynInitL();
        TBool OkToExitL(TInt aButtonId);
// from MEikSrvNotifierBase
        void Release();
        TNotifierInfo RegisterL();
        TNotifierInfo Info() const;
        TPtrC8 StartL(const TDesC8& aBuffer);
        void StartL(const TDesC8& aBuffer, const TAny* aReturnVal, RMessage aMessage);
        void Cancel();
        TPtrC8 UpdateL(const TDesC8& aBuffer);
        
private:
        TNotifierInfo iInfo;
        RMessage iMessage;
        const TAny* iReturnVal;
        };

2. Example cpp implementation:

//
// CknMmc.cpp
//
#include "CknMmc.h"

#include <EikSecEd.h>
#include <EikEnv.h>
#include <EikBtGpc.h>
#include <BaUtils.h>



#include <notifiertest.rsg>
//#include "CknNtfy.hrh"

// local copy for now...will be defined in a header
const TUid KScreenOutputChannel={0x100065aa};

void CCknMmcNotifier::Release()
        {
        delete this;
        }

CCknMmcNotifier::TNotifierInfo CCknMmcNotifier::RegisterL()
        {
        iInfo.iUid=KCkonMmcNotifierUid;
        iInfo.iChannel=KScreenOutputChannel;
        iInfo.iPriority=ENotifierPriorityVHigh;
        return iInfo;
        }

CCknMmcNotifier::TNotifierInfo CCknMmcNotifier::Info() const
        { // return notifier info
        return iInfo;
        }

TInt CCknMmcNotifier::DisplayNotifier()
        {
        RouseSleepingDialog();
        return KErrNone;
        }

TPtrC8 CCknMmcNotifier::StartL(const TDesC8& /*aBuffer*/)
        { // will not get called as this is a get response notifier
                RouseSleepingDialog();
                

        return TPtrC8();
        }

void CCknMmcNotifier::StartL(const TDesC8& /*aBuffer*/, const TAny* aReturnVal, RMessage aMessage)
        { // display the notifier
        const TAny* rdes=aMessage.Ptr2();
        TInt desLength=aMessage.Client().GetDesLength(rdes);
        if(desLength!=(TInt)sizeof(TMediaPswdReplyNotifyInfoV1))
                User::Leave(KErrGeneral);
// non waiting dialog
        iMessage=aMessage;
        iReturnVal=aReturnVal;
        RouseSleepingDialog();
        }

void CCknMmcNotifier::Cancel()
        {
        ExitSleepingDialog();
        //static_cast<CEikSecretEditor*>(Control(ECkonMmcNotifyLabel))->Reset();
        //if (iMessage.MessagePtr()!=RMessagePtr())
                //{
                //iMessage.Complete(KErrCancel);
                //}
        }

TPtrC8 CCknMmcNotifier::UpdateL(const TDesC8& /*aBuffer*/)
        { // ??
        return TPtrC8();
        }

CCknMmcNotifier* CCknMmcNotifier::NewL()
        { // construct the notifier
        CCknMmcNotifier* self=new (ELeave) CCknMmcNotifier();
        CleanupStack::PushL(self);
        self->ConstructL();
        CleanupStack::Pop();
        return self;
        }

CCknMmcNotifier::~CCknMmcNotifier()
        { // remove sleeping dialog from the stack
        iEikonEnv->RemoveFromStack(this);
        }

CCknMmcNotifier::CCknMmcNotifier()
        {
        }

void CCknMmcNotifier::ConstructL()
        {
//#pragma message ("A problem with wins emulatator. CBA can not be used if SetGloballyCapturing(ETrue) is called")
        //SetGloballyCapturing(ETrue);
        _LIT(KResFileName,"\\System\\Data\\notifiertest.rsc");
        _LIT(KDrive,"z:");
        // hack as Dll::Filename appears to not return the drive for notifiers
        TBuf<2> drive;
        drive=KDrive;
        TFileName fileName;
        Dll::FileName(fileName);
        TParse parse;
        parse.Set(KResFileName, &fileName, &drive);
        fileName=parse.FullName();
        
        BaflUtils::NearestLanguageFile(iEikonEnv->FsSession(),fileName);
//
        TInt offset=iEikonEnv->AddResourceFileL(fileName);
        TRAPD(err,ConstructSleepingAlertDialogL(R_CHECKBOX_DEMO_DIALOG));
        iEikonEnv->DeleteResourceFile(offset);
        User::LeaveIfError(err);
        }

void CCknMmcNotifier::PreLayoutDynInitL()
        { // must not fail in anyway
        }

TBool CCknMmcNotifier::OkToExitL(TInt aButtonId)
        {
        return ETrue;
}

3. Create dll entry implementation file.

/*
============================================================================
Name        : Try_00Dll.cpp 
Author      : HanyMT & basedj
Version     :
Copyright   : Your copyright notice
Description : Try_00Dll.cpp - main DLL source
============================================================================
*/

//  Include Files  

#include <e32std.h>         // GLDEF_C
#include "Try_00.pan"       // panic codes


//  Global Functions

GLDEF_C void Panic(TTry_00Panic aPanic)
// Panics the thread with given panic code
   {
   User::Panic(_L("TRY_00"), aPanic);
   }


//  Exported Functions

EXPORT_C TInt E32Dll(TDllReason /*aReason*/)
// Called when the DLL is loaded and unloaded. Note: have to define
// epoccalldllentrypoints in MMP file to get this called in THUMB.
   {
   return KErrNone;
   }

4. Create a MMP file

Use a custom - and registered - UID3 to identify your notifier. Note the UID2 value which must match the KUidNotifierPlugIn value (0x10005522):

/*
============================================================================
Name        : Try_00.mmp
Author      : HanyMT & Basedj
Version     :
Copyright   : Your copyright notice
Description : This is the project specification file for Try_00.
============================================================================
*/
TARGET                Try_00.dll 
TARGETTYPE            dll 
TARGETPATH            \system\Notifiers 
UID                   0x10005522 0x101f5ac4 
USERINCLUDE           ..\inc 
SYSTEMINCLUDE         \epoc32\include 
DOCUMENT              bld.inf 
DOCUMENT              Try_00.pkg 
SOURCEPATH            ..\data 
RESOURCE              NotifierTest.rss 

SOURCEPATH            ..\src 
SOURCE                cknmmc.cpp 
SOURCE                cknntfy.cpp 

LIBRARY               eiksrv.lib 
LIBRARY               eikcore.lib 
LIBRARY               efsrv.lib 
LIBRARY               eikdlg.lib 
LIBRARY               cone.lib 
LIBRARY               eikcoctl.lib 
LIBRARY               bafl.lib 
LIBRARY               euser.lib 
EXPORTUNFROZEN

5. Call notifier from client app.

Rnotifier r;
r.Connect();
r.StartNotifier(NotifierUID,buf1,buf2);

Observer Pattern in Symbian application
Retrieving IMEI, IMSI, Network Info (Cell Id, Location Code) on 3rd Edition.
Hashtable implementation for Symbian
C++ Inheritance
Using inline assembler within Symbian C++
Cleanup support for ResetAndDestroy()
Simplify Two Phase Constructor in Symbian
Guidelines for Code Optimisation