FAQ-0499 How can I launch an application and wait until it's finished to do something?


FAQ-0499 How can I launch an application and wait until it's finished to do something?

» Symbian OS » Developer Knowledgebase » FAQ-0499

Classification:	C++	Category:	Threads & Processes
Created:	06/23/2000	Modified:	01/16/2002
Number:	FAQ-0499
Platform:	ER5, Symbian OS v6.0, Symbian OS v6.1

Question:
How can I launch an application and wait until it's finished to do something?

Answer:
This can be done via a simple Active Object. Consider this class:

//
// CThreadLogon
//
class CEikBusyMsgWin;
class CExampleAppUi;
class CThreadLogon : public CActive

{public:

CThreadLogon(CExampleAppUi& aAppUi);
~CThreadLogon();
void ConstructL();
void Request(const TThreadId& aId);private:

void DoCancel();
void RunL();private:

RThread iThread;
CExampleAppUi& iAppUi;
CEikBusyMsgWin* iBusyMsg;
HBufC* iBusyText;
};
CThreadLogon::CThreadLogon(CExampleAppUi& aAppUi)

: CActive(EActivePriorityIpcEventsHigh), iAppUi(aAppUi)
{
}
CThreadLogon::~CThreadLogon()

{
Cancel();
delete iBusyMsg;
User::Free(iBusyText);
}
void CThreadLogon::ConstructL()

{
CEikonEnv* eikonEnv=CEikonEnv::Static();
iBusyMsg=new(ELeave) CEikBusyMsgWin(*eikonEnv);
iBusyMsg->ConstructL(eikonEnv->RootWin());
iBusyText=eikonEnv->AllocReadResourceL(R_EXAMPLE_WAITING_FOR_APP);
CActiveScheduler::Add(this);
}
void CThreadLogon::DoCancel()

{
iBusyMsg->CancelDisplay();
iThread.LogonCancel(iStatus);
iThread.Close();
}
void CThreadLogon::RunL()

{
iBusyMsg->CancelDisplay();
iThread.Close();
iAppUi.LogonCallBackL();
}
void CThreadLogon::Request(const TThreadId& aId)

{
TInt err=iThread.Open(aId);
if (err)

{
TRequestStatus* pS=&iStatus;
User::RequestComplete(pS,err);
}else

iThread.Logon(iStatus);SetActive();
iBusyMsg->StartDisplay(iBusyText->Des(),EHRightVBottom);
}
All you now need to to is add a CThreadLogon* iThreadLogon member to your AppUi, do:

iThreadLogon=new(ELeave) CThreadLogon(*this);
iThreadLogon->ConstructL();
in the AppUi's constructor and finally construct a callback procedure in your AppUI. For example, this will bring your application to the foreground and show a simple message:

void CExampleAppUi::LogonCallBackL()

{
iEikonEnv->SetBusy(EFalse);

RWsSession& ws = iEikonEnv->WsSession();
RWindowGroup& rw = iEikonEnv->RootWin();
TInt winId = rw.Identifier();
TApaTask tApatsk(ws);
tApatsk.SetWgId(winId);
tApatsk.BringToForeground();

iEikonEnv->InfoWinL(R_EXAMPLE_APP_FINISHED);
}
When launching the app initially, you need to ensure the thread id is passed to the iThreadLogon AO. This could be done as follows:

iThreadLogon->Request(EikDll::StartAppL(*cmdLine));
iEikonEnv->SetBusy(ETrue);