How to perform file IO using QDataStream in Qt for Symbian

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Reviewer Approved

ID	...	Creation date	27 January 2009
Platform	S60 3rd Edition FP1, S60 3rd Edition FP2, S60 5th Edition	Tested on devices	Emulator
Category	Qt for Symbian	Subcategory

Keywords (APIs, classes, methods, functions): QDataStream

Overview

This code snippet demonstrates how to use QDataStream for performing file read and write in Qt for S60.

In my previous article same function would be perform using QTextStream.

Preconditions

Download and Install latest version Qt for Symbian - Installation packages which has links on how to install the latest version

Various Functions

Sets the serialization byte order to bo.

in.setByteOrder(QDataStream::LittleEndian);

Sets the version number of the data serialization format to v

QDataStream out(file);
out.setVersion(QDataStream::Qt_4_0);

Source File

More About QDataStream: http://pepper.troll.no/s60prereleases/doc/qdatastream.html

#include "fileIO.h"
#include <QFile>
#include <QLabel>
#include <QDataStream>
fileIO::fileIO(QWidget *parent)
    : QWidget(parent)
{
	QFile file("c://test.txt");
	file.open(QIODevice::WriteOnly);
	QDataStream out(&file);   // we will serialize the data into the file
	out << "welcome to the Qt World";   // serialize a string
	file.close();
 
 
	QFile read("c://test.txt");
	read.open(QIODevice::ReadOnly);
	QDataStream in(&read);    // read the data serialized from the file
	QString str;
	in >> str;
}
 
fileIO::~fileIO()
{
 
}