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Why it is required?
When you draw something in exe (without CONE environment), you will not get redraw event automatically. It is required because when some part of your rect gets invalid than you have to validate it again. Possible cases when your rect might get invalid are opening other aap, receive call, receive SMS etc.

How to implement it?
We have to request redraw events from the window server, we can do this by the RedrawReady method of window server. We also need to create an active object for redraw events.

CMyReDraw::CMyReDraw(RWsSession& aWsSession): CActive(CActive::EPriorityStandard), iWsSession(aWsSession)
{
	CActiveScheduler::Add(this);
 
	iStatus = KRequestPending;
	//iWsSession is your window server session and assuming u have created it.
	iWsSession.RedrawReady(&iStatus);  
	SetActive();
}
 
CMyReDraw::~CMyReDraw()
{
	Cancel();
}
 
void CMyReDraw::RunL()
{
	TWsRedrawEvent e;
	//GetRedraw will give you redraw event
	iWsSession.GetRedraw(e);
 
	//you can call your drawing function here.
 
	iStatus = KRequestPending;
	//you should not call RedrawReady again until you've either called GetRedraw() or RedrawReadyCancel().
	iWsSession.RedrawReady(&iStatus);
	SetActive();
}
 
void CMyReDraw::DoCancel()
{
	iWsSession.RedrawReadyCancel();
}

Related Links:

• How to capture Keyevents in thread or exe
• Graphics in EXE
• How to Launch an EXE and Pass Command Line Arguments
• How to start EXE from an EXE in 3rd Edition
• Displaying controls in Symbian exe programs

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