Archived:Establishing a Bluetooth connection using Symbian C++
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Contents |
Overview
The following code example listens to an advertised (KBT_serviceID=0x10ff) Bluetooth connection and reads or send data through it. Advertising a certain Bluetooth service is explained in Advertising Bluetooth services using Symbian C++.
MMP file
The following capabilities and libraries are required:
CAPABILITY LocalServices NetworkServices
LIBRARY esock.lib
LIBRARY bluetooth.lib
LIBRARY btmanclient.lib
Header file
Bluetooth connection listener.
#include <e32base.h>
#include <bt_sock.h>
const TInt KReceivedBufferSize = 40;
const TInt KSizeOfListenQueue = 5;
_LIT(KRfComm,"RFCOMM");
// The service id that identifies the service. This id will be
// used when advertising the service and discovering the service.
#define KBT_serviceID 0x10ff
class CBluetoothListener : public CActive
{
public:
static CBluetoothListener* NewL(RSocketServ& aSocketServ);
static CBluetoothListener* NewLC(RSocketServ& aSocketServ);
~CBluetoothListener();
void StartListenerL(TInt& aChannel);
void StopListener();
void SendData(const TDesC8& aData);
TBool IsConnected();
protected: // From CActive
void RunL();
void DoCancel();
TInt RunError(TInt aError);
private:
CBluetoothListener(RSocketServ& aSocketServ);
void ConstructL();
void ReceiveData();
public: // data
// Listening socket
RSocket iListenSock;
// Accepted socket
RSocket iSock;
// Length of received data
TSockXfrLength iLen;
// Buffer holding received data
TBuf8<KReceivedBufferSize> iBuffer;
// Socket server handle
RSocketServ& iSocketServ;
// Listener connection status
TBool iIsConnected;
// State of the listener
enum TState
{
ENone = 1,
EConnecting,
EWaiting,
ESending
};
TState iState;
};
Source file
CBluetoothListener* CBluetoothListener::NewL(RSocketServ& aSocketServ)
{
CBluetoothListener* self = CBluetoothListener::NewLC(aSocketServ);
CleanupStack::Pop(self);
return self;
}
CBluetoothListener* CBluetoothListener::NewLC(RSocketServ& aSocketServ)
{
CBluetoothListener* self = new (ELeave) CBluetoothListener(aSocketServ);
CleanupStack::PushL(self);
self->ConstructL();
return self;
}
void CBluetoothListener::ConstructL()
{
}
CBluetoothListener::CBluetoothListener(RSocketServ& aSocketServ):
CActive(CActive::EPriorityStandard),
iSocketServ(aSocketServ),
iIsConnected(EFalse),
iState(ENone)
{
CActiveScheduler::Add(this);
}
CBluetoothListener::~CBluetoothListener()
{
Cancel();
StopListener();
}
void CBluetoothListener::StartListenerL(TInt& aChannel)
{
if ( iState!=ENone )
{
User::Leave(KErrInUse);
}
// Set this active object to connecting state
iState=EConnecting;
// Load protocol, RFCOMM
TProtocolDesc pdesc;
User::LeaveIfError(iSocketServ.FindProtocol(KRfComm(), pdesc));
// Open a socket
User::LeaveIfError(
iListenSock.Open(iSocketServ,
pdesc.iAddrFamily,pdesc.iSockType,KRFCOMM)
);
// Get listening channel
User::LeaveIfError(iListenSock.GetOpt(KRFCOMMGetAvailableServerChannel,
KSolBtRFCOMM, aChannel));
// Bluetooth socket address object
TBTSockAddr btsockaddr;
btsockaddr.SetPort(aChannel);
// Bind bluetooth socket
User::LeaveIfError(iListenSock.Bind(btsockaddr));
// Listen on port
iListenSock.Listen(KSizeOfListenQueue);
// Set security
TBTServiceSecurity secSettings;
TUid settingsUID;
settingsUID.iUid = KBT_serviceID;
secSettings.SetUid(settingsUID);
secSettings.SetAuthentication(EFalse);
secSettings.SetAuthorisation(EFalse);
secSettings.SetEncryption(EFalse);
// Attach the security settings.
btsockaddr.SetSecurity(secSettings);
// Close old accepted socket if open
iSock.Close();
// Open blank socket and pass it to accept to be assigned a proper
// socket upon completion of Accept()
User::LeaveIfError(iSock.Open(iSocketServ));
// Set to accept incoming connections, active object will handle
iListenSock.Accept(iSock,iStatus);
SetActive();
}
void CBluetoothListener::StopListener()
{
if ( iState!=ENone )
{
iSock.Close();
iListenSock.Close();
iState=ENone;
}
}
void CBluetoothListener::ReceiveData()
{
// Set state to waiting - for RunL()
iState = EWaiting;
// Make async request
iSock.RecvOneOrMore(iBuffer, 0, iStatus, iLen);
// Set as active to get the async req response (iState) in RunL()
SetActive();
}
void CBluetoothListener::SendData(const TDesC8& aData)
{
if ( iState!=EWaiting )
return;
// Cancel any read requests on socket
Cancel();
// Try to send message by writing to socket
// - set the state of this active object to "sending"
iState=ESending;
// - make async socket write request
iSock.Write(aData, iStatus);
// - start waiting async req response (iState) from active scheduler
SetActive();
}
void CBluetoothListener::RunL()
{
if ( iStatus!=KErrNone )
{
StopListener();
TODO: Add error handling
return;
}
switch (iState)
{
case EConnecting:
{
// Connected listening socket!
ReceiveData();
break;
}
case EWaiting:
{
// Returned from receiving data
if(iState!=KErrNone)
{
// add the error handling / re-reading code here..
// not needed in this example
}
HBufC* text = HBufC::NewLC(iBuffer.Length());
text->Des().Copy(iBuffer);
// TODO: Do something with received data
CleanupStack::PopAndDestroy(text);
// Start expecting next data to be read
ReceiveData();
break;
}
case ESending:
{
// Returned from sending the date, check the state
if(iState!=KErrNone)
{
// add the error handling / re-sending code here..
// not needed in this example
}
// Start expecting next data to be read
ReceiveData();
break;
}
default:
break;
}
}
TInt CBluetoothListener::RunError(TInt aError)
{
// TODO: Add the error handling
return KErrNone;
}
void CBluetoothListener::DoCancel()
{
iSock.CancelAll();
iListenSock.CancelAll();
}
TBool CBluetoothListener::IsConnected()
{
return iIsConnected;
}
See also
Archived:Discovering Bluetooth devices using Symbian C++
Archived:Discovering Bluetooth services using Symbian C++
Advertising Bluetooth services using Symbian C++
Archived:RHostResolver and redundant display of access point selection dialog (Known Issue)
Example application
This code snippet has been used in the S60 Platform: Bluetooth Point-to-multipoint Example application.
