Display wait note between HTTP response delay

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23 Sep
2009

Article Review by deepikagohil (20090923)

This article represents code to display wait note between HTTP response delay. Sometimes it gets too long to get the response from HTTP for the request issued. The demostrated example displays a dialog with "Please wait" text during this waiting moment.

The header file used for doing this task is <AknWaitNoteWrapper.h> and our test class is derived from MAknBackgroundProcess and MHTTPObserver. All the essential libraries that should be added are also mentioned at the top. The mandatory changes that should be done in the resource file are also illustrated in this article. Though the article does not contain any overview, the code presented here contains comments to make it understandable with less efforts.

This article can be beneficail to beginners to understand the API for creating display notes between HTTP response delay.

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This Symbian C++ code snippet shows how to display a wait note while waiting for a http response.

Article Metadata

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Article

Created: sinhashivam (16 May 2007)

Last edited: hamishwillee (25 Jan 2012)

Project file (.mmp)

LIBRARY       avkon.lib
LIBRARY       eikcdlg.lib
LIBRARY       eikctl.lib

RSS file (.rss)

//----------------------------------------------------
//   
//    r_wait_note_http_request
//    Display wait note
//
//----------------------------------------------------
//
RESOURCE DIALOG r_wait_note_http_request
	{
	flags=EAknWaitNoteFlags;
	items =
		{
		DLG_LINE
			{
			type = EAknCtNote;
			id = EWaitNoteId;
			control = AVKON_NOTE
				{
				layout = EWaitLayout;
				singular_label = "Please wait..."
				imagefile = "z:\\system\data\avkon.mbm";
				imageid = EMbmAvkonQgn_note_progress;
				imagemask = EMbmAvkonQgn_note_progress_mask;
				animation = R_QGN_GRAF_WAIT_BAR_ANIM;
				};
			}
		};
	}

Header file (.h)

#ifndef __TestClass_H__
#define __TestClass_H__
 
#include "HTTPClientEngine.h"
#include <AknWaitNoteWrapper.h>
 
 
class TestClass: public MHTTPObserver,public MAknBackgroundProcess
{
public:
 
	static TestClass* NewLC();
	static TestClass* NewL();
 
	void ConstructL();
	TestClass();
	virtual ~TestClass();
        void IssueHTTPRequest(); 
 
	/*
	* HTTP Callback Methods
	*
	*/
	virtual	void ClientEvent(const TDesC& aEventDescription);
	virtual	void ClientBodyReceived(const TDesC8& aBodyData);
 
       /*
	*	From MAKnBackgroundObserver
	*
	*/
	TBuf<32> Status;
	RTimer iTimeWaster;
 
   private:
	TBool iDialogDismissed;
	void DialogDismissedL(TInt aButtonId);
	TBool IsProcessDone() const;
	void ProcessFinished();
	void StepL();
 
private:
	HBufC8*				iHTTPResponse;
	CHTTPClientEngine*	        iHTTPClient;
	CAknWaitNoteWrapper*		waitNoteWrapper;
	};
 
#endif __TestClass_H__

Source file (cpp)

// TestClass.cpp: implementation of the CTestClassclass.
//
//////////////////////////////////////////////////////////////////////
 
#include "TestClass.h" 
#include <e32std.h>
#include <eikmenup.h>
#include <e32base.h>
#include <aknnotewrappers.h>
#include <StringLoader.h> 
/*
============================================================================
Name        : CTestClass from TestClass.h
Author      : shivam
Version     : 
 
============================================================================
*/
 
CTestClass ::CTestClass()
{
}
 
 
CTestClass::~CTestClass()
{
	if(iHTTPClient)
	{
		delete iHTTPClient;
		iHTTPClient=NULL;
	}
 
	if(iHTTPResponse)
	{
		delete iHTTPResponse;
		iHTTPResponse=NULL;
	}
 
	iTimeWaster.Close();
 
	delete this->waitNoteWrapper;
	this->waitNoteWrapper=NULL;
}
 
void CTestClass::CTestClass()
{
	iHTTPClient=CHTTPClientEngine::NewL(*this);
	iHTTPResponse=NULL;
 
	waitNoteWrapper = CAknWaitNoteWrapper::NewL();
	iTimeWaster.CreateLocal();
}
 
CTestClass* CTestClass::NewL()
{
	CTestClass* self = CTestClass::NewLC();
	CleanupStack::Pop(self);
	return self;
}
 
CTestClass* CTestClass::NewLC()
{
	CTestClass* self = new (ELeave) CTestClass();
	CleanupStack::PushL(self);
	self->ConstructL();
	return self;
}
 
 
//=========================================================================
//ClientBodyReceived() -- HTTP Callback Function.This will get the response 
// body data.
//returns -- None
//
//==========================================================================
 
void CTestClass::ClientBodyReceived(const TDesC8& aBodyData)
{
	if(!iHTTPResponse)
		{
			iHTTPResponse = HBufC8::NewL(aBodyData.Length());
		}
		else
		{
iHTTPResponse = 
     iHTTPResponse->ReAllocL(iHTTPResponse->Length()+aBodyData.Length());		
		}
 
		TPtr8 ptr_bufNoteData8=iHTTPResponse->Des();
		ptr_bufNoteData8.Append(aBodyData);
}
 
 
//=========================================================================
//ClientEvent() -- HTTP Callback function
//aEventDescription -- The transaction events
//returns -- None
//
//==========================================================================
 
void CTestClass::ClientEvent(const TDesC& aEventDescription)
{
	this->Status.Copy(aEventDescription);
 
	_LIT(KTransactionSuccessful, "Transaction Successful");
	if(aEventDescription==KTransactionSuccessful)
	{
		//Handle HTTP Response
	}
}
 
//=========================================================================
//
//IssueHTTPRequest()  -- Issue HTTP request
//
//
//==========================================================================
 
void CConnector::IssueHTTPRequest()
{
	 iRSSFeed = aCurrentFeed;	
	 Status.Copy(_L("Init"));	
	 TBuf8<256> uri8;
	 uri8.Append(_L("http://www.developer.nokia.com/"));
 
	// Start transaction
	iHTTPClient->IssueHTTPGetL(uri8);
 
if (!waitNoteWrapper->ExecuteL(R_WAIT_NOTE_HTTP_REQUEST, *this,ETrue)) 
{
		iHTTPClient->CancelTransaction();
}
 
}
//=========================================================================
//StepL() -- Used by the Wait bar to increment the timer
//Inherited from MAknBackgroundObserver
//
//==========================================================================
 
void CTestClass::StepL()
{
	TRequestStatus status;
	TInt delay = 100000; // 1 second
	iTimeWaster.After(status, delay);
	User::WaitForRequest(status); 
 
}
 
 
//=========================================================================
//ProcessFinished() -- Diminishes the wait bar when the http process is finished
//
//Inherited from MAknBackgroundObserver
//==========================================================================
 
void CTestClass::ProcessFinished()
{
	iTimeWaster.Cancel();
	this->Status.Delete(0,this->Status.Length());
}
 
 
//=========================================================================
//IsProcessDone() -- Checks whethet the HTTP request is complete or not
//returns : True/False
//Inherited from MAknBackgroundObserver
//==========================================================================
 
TBool CTestClass::IsProcessDone() const
{
	_LIT(KTransactionSuccessful, "Transaction Successful");
	TPtrC istatus(this->Status);
	return(istatus==KTransactionSuccessful);
}
 
//=========================================================================
//DialogDismissedL() -- Called if the wait bar is stopeed in between
//Inherited from MAknBackgroundObserver
//
//==========================================================================
 
void CTestClass::DialogDismissedL(TInt /*aButtonId*/)
{
}