From Forum Nokia Wiki

ID	CS000910	Creation date	April 22, 2008
Platform	S60 3rd Edition, FP1	Tested on devices	Nokia N95
Category	Symbian C++	Subcategory	Bluetooth

Keywords (APIs, classes, methods, functions): RNotifier,TBTDeviceSelectionParamsPckg, TBTDeviceResponseParamsPckg,RNotifier::StartNotifierAndGetResponse(), RNotifier::CancelNotifier(),RNotifier::Close()

Overview

This code snippet describes the Bluetooth device discovery mechanism provided by the S60 UI platform. The RNotifier class can be used to perform device discoveries where user interaction is required. By using the TBTDeviceSelectionParams class it is also possible to restrict the search to a more specific subset of devices.

This snippet can be self-signed.

MMP file

The following libraries are required:

LIBRARY bluetooth.lib
LIBRARY btextnotifiers.lib 
LIBRARY btdevice.lib

Header file

#ifndef BTDEVICEFINDER_H_
#define BTDEVICEFINDER_H_
 
#include <e32base.h>
#include <BTExtNotifiers.h> //TBTDeviceSelectionParamsPckg,TBTDeviceResponseParamsPckg
     class MBTDeviceFinderNotify
         {
         public:
                 virtual void BTDeviceSelected() = 0;
         };
 
     class CBTDeviceFinder: public CActive
         {
         public:
                 static CBTDeviceFinder* NewL(const TInt aPriority,
                                          MBTDeviceFinderNotify& aNotify);
                 ~CBTDeviceFinder();
         public:
                 void DiscoverDevicesL();
                 void SetSelectionParams(const TBTDeviceSelectionParams& aFilter);
                 const TBTDeviceResponseParams& ResponseParams();
         protected:
                 void RunL();
                 void DoCancel();
         private:
                 CBTDeviceFinder(const TInt aPriority,MBTDeviceFinderNotify& aNotify);
                 void ConstructL(void);
         private:
             RNotifier                     iSelectorNotifier;
             MBTDeviceFinderNotify&        iNotify;                
             TBTDeviceSelectionParamsPckg  iSelectParamsBuf;
             TBTDeviceResponseParamsPckg   iResponseParamsBuf;
             TBool                         iConnected;
         };
#endif /*BTDEVICEFINDER_H_*/

Source file

#include "BTDeviceFinder.h"
 
CBTDeviceFinder::CBTDeviceFinder(const TInt aPriority,
                 MBTDeviceFinderNotify& aNotify)
:CActive(aPriority),iNotify(aNotify),iConnected(EFalse)
{
}
 
CBTDeviceFinder::~CBTDeviceFinder()
{        
  Cancel();
  if (iConnected)
    {
    iSelectorNotifier.CancelNotifier( KDeviceSelectionNotifierUid );
    iSelectorNotifier.Close();
    }
}
 
CBTDeviceFinder* CBTDeviceFinder::NewL(const TInt aPriority,
                                MBTDeviceFinderNotify& aNotify)
{
    CBTDeviceFinder* self = new (ELeave) CBTDeviceFinder(aPriority,aNotify);
    CleanupStack::PushL(self);
    self->ConstructL();
    CleanupStack::Pop();
    return self;
}
 
void CBTDeviceFinder::ConstructL(void)
{
  CActiveScheduler::Add(this);
}
 
void CBTDeviceFinder::DoCancel()
{
  iSelectorNotifier.CancelNotifier( KDeviceSelectionNotifierUid );
}
 
void CBTDeviceFinder::RunL()
{
  //the user has selected some device
  if(iStatus.Int() == KErrNone)
        {
        iNotify.BTDeviceSelected();
        }
  else //an error has occurred
        {
        User::Leave(iStatus.Int());
        }
}
 
void CBTDeviceFinder::DiscoverDevicesL()
{
  if (!iConnected)
        {
        User::LeaveIfError(iSelectorNotifier.Connect());
        iConnected = ETrue;
        }  
 
  iSelectorNotifier.StartNotifierAndGetResponse(iStatus,
                  KDeviceSelectionNotifierUid, 
                  iSelectParamsBuf, 
                  iResponseParamsBuf);
  SetActive();
}
 
void CBTDeviceFinder::SetSelectionParams(const TBTDeviceSelectionParams& aFilter)
{
  iSelectParamsBuf = aFilter;
}
 
const TBTDeviceResponseParams& CBTDeviceFinder::ResponseParams()
{
  return iResponseParamsBuf();
}

Using CBTDeviceFinder class

• In the header file:

class CBTDeviceFinder;
 
class CTestingAppUi : public CAknAppUi, MBTDeviceFinderNotify
  {
public:
  //...
  //from MBTDeviceFinderNotify
  void BTDeviceSelected();
  //...  
private:  
  //...
  CBTDeviceFinder* iFinder;
  };

• In the source file:

#include "btdevicefinder.h"
#include <btdevice.h> //TBTDeviceClass, TBTDeviceName 
#include <bttypes.h> //TBTDevAddr
 
void CTestingAppUi::ConstructL()
  {
  CActive::TPriority priority(CActive::EPriorityUserInput);
  iFinder = CBTDeviceFinder::NewL(priority, *this);
  }
 
CTestingAppUi::~CTestingAppUi()
  {
  delete iFinder;
  }
 
void CTestingAppUi::SelectDeviceL()
  {
  /* search only within a specific subset of devices  
  TBTDeviceSelectionParams selectionFilter;
  TBTDeviceClass deviceFilter(EMajorServiceObjectTransfer, EMajorDevicePhone, 
        EMinorDevicePhoneUnclassified |
         EMinorDevicePhoneCellular |
        EMinorDevicePhoneCordless | 
         EMinorDevicePhoneSmartPhone |
         EMinorDevicePhoneWiredModem |
        EMinorDevicePhoneCommonISDNAccess );
 
  selectionFilter.SetDeviceClass(deviceFilter);
  iFinder->SetSelectionParams(selectionFilter);
  */
 
  iFinder->DiscoverDevicesL();   
  }
 
void CTestingAppUi::BTDeviceSelected()
  {
  //Do something when BT device is selected
  //e.g. get details of the device the user selected    
  //TBTDeviceResponseParams response = iFinder->ResponseParams();  
  //TBTDevAddr deviceAddress = response.BDAddr();
  //TBTDeviceName deviceName = response.DeviceName();
  //TBTDeviceClass deviceClass = response.DeviceClass();
  }

Postconditions

The Bluetooth device selection dialog is shown to the user through the notifier framework.