From Forum Nokia Wiki

ID	...	Creation date	June 13, 2009
Platform	S60 3rd Edition, FP1, FP2 S60 5th Edition	Tested on devices	Nokia 5800 XpressMusic
Category	Qt for Symbian	Subcategory

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

Overview

This code snippets shows how to generate XML using QXmlStreamWriter. The QXmlStreamWriter class provides an XML writer with a simple streaming API.

QXmlStreamWriter is the pendent to QXmlStreamReader for writing XML. Like its related class, it operates on a QIODevice specified with setDevice(). Element tags are opened with writeStartElement() followed by writeAttribute() or writeAttributes(), element content, and then writeEndElement(). A shorter form writeEmptyElement() can be used to write empty elements, followed by writeAttributes().

This snippet can be self-signed. As it does not use any API which require developer/certified signing.

Preconditions

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

Headers files

#include <QXmlStreamWriter>
 
class GenerateXML : public QMainWindow
{
    Q_OBJECT
 
public:
	GenerateXML(QWidget *parent = 0);
    ~GenerateXML();
	//call this function to create xml
    void CreateXMLFile();
 
private:
    Ui::GenerateXMLClass ui;
	//variable having data from which we have to generate xml.
	QMap<QString,QString> firstname;
	QMap<QString,QString> surname;
	QMap<QString,QString> phoneNumber;
};

Source

#include "GenerateXML.h"
#include <QMap>
#include <QFile>
#include <QMessageBox>
#include <QXmlStreamWriter>
#include <QMapIterator>
 
GenerateXML::GenerateXML(QWidget *parent)
    : QMainWindow(parent)
{
	ui.setupUi(this);
	setWindowTitle("Generate XML");
 
	/* Assuming user rerived data from which he wants to creare XML.
	* lets we have data of 5 user to create XML.
	*/
	firstname.insertMulti("firstname", "abc");
	firstname.insertMulti("firstname", "ghi");
	firstname.insertMulti("firstname", "mno");
	firstname.insertMulti("firstname", "stu");
	firstname.insertMulti("firstname", "yza");
 
	surname.insertMulti("surname", "def");
	surname.insertMulti("surname", "jkl");
	surname.insertMulti("surname", "pqr");
	surname.insertMulti("surname", "vwx");
	surname.insertMulti("surname", "bcd");
 
	phoneNumber.insertMulti("number", "12345");
	phoneNumber.insertMulti("number", "67890");
	phoneNumber.insertMulti("number", "12356");
	phoneNumber.insertMulti("number", "87654");
	phoneNumber.insertMulti("number", "756776");
 
	/* call method to generate XML */
	CreateXMLFile();
}
 
void GenerateXML::CreateXMLFile()
{
    /* For testing purpose, we generate in C drives,
	QFile file("c://contacts.xml");
 
	/*open a file */
	if (!file.open(QIODevice::WriteOnly))
	{
	/* show wrror message if not able to open file */
	QMessageBox::warning(0, "Read only", "The file is in read only mode");
	}	
	else
	{
		/*if file is successfully opened then create XML*/
		QXmlStreamWriter* xmlWriter = new QXmlStreamWriter();
		/* set device (here file)to streamwriter */
		xmlWriter->setDevice(&file);
		/* Writes a document start with the XML version number version. */
		xmlWriter->writeStartDocument();
		/* Writes a start element with name,
		* Subsequent calls to writeAttribute() will add attributes to this element.
		 here we creating a tag <persons>*/
		xmlWriter->writeStartElement("persons");
 
		/* create mapiterator to iterate through maps*/
		QMapIterator<QString, QString> i(firstname);
		QMapIterator<QString, QString> j(surname);
		QMapIterator<QString, QString> k(phoneNumber);
 
		/*this while loop generates <person> tag with attributes and CDATA in each execution.
		* currently we have 5 element in map so loop creates 5 tags.
		*/
		while (i.hasNext() && j.hasNext() && k.hasNext()) 
	    {
			i.next(); j.next();	k.next();
			/* create tag person */
			xmlWriter->writeStartElement("person");
			/*add one attribute and its value*/
			xmlWriter->writeAttribute(i.key(), i.value());
			/*add one attribute and its value*/
			xmlWriter->writeAttribute(j.key(), j.value());
			/*add one attribute and its value*/
			xmlWriter->writeAttribute(k.key(), k.value());
			/*add character data to tag person */
			xmlWriter->writeCharacters ("kamlesh");
			/*close tag person  */
			xmlWriter->writeEndElement();
 
	    } 
	    /*end tag persons*/
		xmlWriter->writeEndElement();
		/*end document */
		xmlWriter->writeEndDocument();
               delete xmlWriter;
	}
}
 
GenerateXML::~GenerateXML()
{
 
}

Postconditions

The code snippet is expected to generate XML as shown below.

<?xml version="1.0" encoding="UTF-8" ?> 
- <persons>
  <person firstname="yza" surname="bcd" number="756776">kamlesh</person> 
  <person firstname="stu" surname="vwx" number="87654">kamlesh</person> 
  <person firstname="mno" surname="pqr" number="12356">kamlesh</person> 
  <person firstname="ghi" surname="jkl" number="67890">kamlesh</person> 
  <person firstname="abc" surname="def" number="12345">kamlesh</person> 
  </persons>

External links

• QXmlStreamWriter: QXmlStreamWriter reference

Internal links

• Using QXmlStreamReader to parse XML

Code Example

• The Code Example will generate XML and is tested on Nokia 5800 XpressMusic.