QSettings and xml

Imhotep

I'm trying to work with QSettings and xml file. This is my attempt

file.h

@
#include <QSettings>

#ifndef QCONTROLPANEL_H
#define QCONTROLPANEL_H

class QControlPanel : public QDialog
{
Q_OBJECT

public:
explicit QControlPanel(QWidget *parent = 0);

~QControlPanel();

public slots:
bool readXmlFile(QIODevice &device, QSettings::SettingsMap &map);
bool writeXmlFile(QIODevice &device, const QSettings::SettingsMap &map);

private:
QSettings *settings;

private slots:

signals:

};

#endif // QCONTROLPANEL_H
@

file .cpp

@
// —› QControlPanel methods ‹—

#include "QControlPanel.h"

QControlPanel::QControlPanel(QWidget *parent) :
QDialog(parent)
{
bool readXmlFile(QIODevice &device, QSettings::SettingsMap &map);
bool writeXmlFile(QIODevice &device, const QSettings::SettingsMap &map);

QSettings::Format XmlFormat = QSettings::registerFormat("xml", readXmlFile, writeXmlFile);
settings = new QSettings(XmlFormat, QSettings::UserScope, "Organisation", "Name");

}

QControlPanel::~ QControlPanel()
{
}

bool QControlPanel::readXmlFile(QIODevice &device, QSettings::SettingsMap &map) {
QXmlStreamReader xmlReader(&device);
QStringList elements;

// Solange Ende nicht erreicht und kein Fehler aufgetreten ist
while (!xmlReader.atEnd() && !xmlReader.hasError()) {
// Nächsten Token lesen
xmlReader.readNext();

// Wenn Token ein Startelement
if (xmlReader.isStartElement() && xmlReader.name() != "Settings") {
  // Element zur Liste hinzufügen
  elements.append(xmlReader.name().toString());
// Wenn Token ein Endelement
} else if (xmlReader.isEndElement()) {
  // Letztes Element löschen
  if(!elements.isEmpty()) elements.removeLast();
// Wenn Token einen Wert enthält
} else if (xmlReader.isCharacters() && !xmlReader.isWhitespace()) {
  QString key;

  // Elemente zu String hinzufügen
  for(int i = 0; i < elements.size(); i++) {
    if(i != 0) key += "/";
    key += elements.at(i);
  }

  // Wert in Map eintragen
  map[key] = xmlReader.text().toString();
}

}

// Bei Fehler Warnung ausgeben
if (xmlReader.hasError()) {
qWarning() << xmlReader.errorString();
return false;
}

return true;
}

bool QControlPanel::writeXmlFile(QIODevice &device, const QSettings::SettingsMap &map) {
QXmlStreamWriter xmlWriter(&device);

xmlWriter.setAutoFormatting(true);
xmlWriter.writeStartDocument();
xmlWriter.writeStartElement("Settings");

QStringList prev_elements;
QSettings::SettingsMap::ConstIterator map_i;

// Alle Elemente der Map durchlaufen
for (map_i = map.begin(); map_i != map.end(); map_i++) {

QStringList elements = map_i.key().split("/");

int x = 0;
// Zu schließende Elemente ermitteln
while(x &lt; prev_elements.size() && elements.at(x) == prev_elements.at(x)) {
  x++;
}

// Elemente schließen
for(int i = prev_elements.size() - 1; i >= x; i--) {
  xmlWriter.writeEndElement();
}

// Elemente öffnen
for (int i = x; i < elements.size(); i++) {
  xmlWriter.writeStartElement(elements.at(i));
}

// Wert eintragen
xmlWriter.writeCharacters(map_i.value().toString());

prev_elements = elements;

}

// Noch offene Elemente schließen
for(int i = 0; i < prev_elements.size(); i++) {
xmlWriter.writeEndElement();
}

xmlWriter.writeEndElement();
xmlWriter.writeEndDocument();

return true;
}
@

But after debug, Qt Creator tells me these error messages:

C:\Users\Marco\untitled4\QControlPanel.cpp:120: error: undefined reference to writeXmlFile(QIODevice&, QMap<QString, QVariant> const&)' C:\Users\Marco\untitled4\QControlPanel.cpp:120: error: undefined reference to readXmlFile(QIODevice&, QMap<QString, QVariant>&)'
collect2.exe:-1: error: error: ld returned 1 exit status

Could you help me? I have drawn inspiration from this example: http://www.openshots.de/2011/03/qsettings-mit-xml-format/

dheerendra

I don't see any issue here. Can you just do clean and do the build again ?

andreyc

Why do you declare writeXmlFile and readXmlFile again in the lines 8 and 9 in file.cpp above?

andreyc

According to "QSettings::registerFormat":http://qt-project.org/doc/qt-5/qsettings.html#registerFormat documentation the writeFunc and readFunc must be either standalone function or static member functions.
In the "example that you used":http://www.openshots.de/2011/03/qsettings-mit-xml-format/ both functions are standalone functions.

Move both functions out of the class or make them the static functions of the class.

zabdielfer

@andreyc

Hi Andreyc, I have been finding "Qsettings-mit-xml-format", but the link http://www.openshots.de/2011/03/qsettings-mit-xml-format/ is broken, is there some way for i can see this example? thanks

zabdielfer

@zabdielfer said in QSettings and xml:

@andreyc

Hi Andreyc, I have been searching "Qsettings-mit-xml-format", but the link http://www.openshots.de/2011/03/qsettings-mit-xml-format/ is broken, is there some way for i can see this example? thanks

karlheinzreichel

@zabdielfer as @andreyc sayed. You have to change the methods readXmlFile and writeXmlFile to static members..

Especially:
in your header file:
change

bool readXmlFile(QIODevice &device, QSettings::SettingsMap &map);
bool writeXmlFile(QIODevice &device, const QSettings::SettingsMap &map);

to
static bool readXmlFile(QIODevice &device, QSettings::SettingsMap &map);
static bool writeXmlFile(QIODevice &device, const QSettings::SettingsMap &map);

and remove in the implementation file (QControlPanel constructor) the forward declarations

bool readXmlFile(QIODevice &device, QSettings::SettingsMap &map);
bool writeXmlFile(QIODevice &device, const QSettings::SettingsMap &map);

zabdielfer

@karlheinzreichel
thank you, I will try it

zabdielfer

This post is deleted!

zabdielfer

@karlheinzreichel

@zabdielfer
Hi:
how could I get all attributes of a node for example this xml file
<Ajustes>
<Personalizado>
<AjustesECG setting_ecg.V_on="false" setting_ecg.marcapasos="false" setting_ecg.alarm_on_st2="true" />
<AjustesRSP setting_rsp.gain="2" setting_rsp.apnea_delay="1" setting_rsp.alarm_on="true" />
<AjustesNIBP setting_pni.period="2" setting_pni.alarm_sy_on="true" setting_pni.alarm_di_on="true"
<AjustesCO2 setting_cos.apnea_delay="1" setting_cos.compensation="false" setting_cos.alarm_cex_on="true" />
<AjustesNO2 setting_nos.alarm_nex_on="false" setting_nos.alarm_nin_on="false" setting_nos.alarm_nex_lvl="1"
<AjustesTNM setting_nmt.current="0" setting_nmt.period="0" setting_nmt.type="0" setting_nmt.width="0" />
</Personalizado>
<Fabrica>
<AjustesECG setting_ecg.V_on="false" setting_ecg.marcapasos="false" setting_ecg.alarm_on_st2="true" />
<AjustesRSP setting_rsp.gain="2" setting_rsp.apnea_delay="1" setting_rsp.alarm_on="true" />
<AjustesNIBP setting_pni.period="2" setting_pni.alarm_sy_on="true" setting_pni.alarm_di_on="true"
<AjustesCO2 setting_cos.apnea_delay="1" setting_cos.compensation="false" setting_cos.alarm_cex_on="true" />
<AjustesNO2 setting_nos.alarm_nex_on="false" setting_nos.alarm_nin_on="false" setting_nos.alarm_nex_lvl="1"
<AjustesTNM setting_nmt.current="0" setting_nmt.period="0" setting_nmt.type="0" setting_nmt.width="0" />
</Fabrica>
</Ajustes>

Taz742

@zabdielfer
QXmlStreamReader * rdr = new QXmlStreamReader("path");

while (!rdr->atEnd()) {

    QXmlStreamReader::TokenType token = rdr->readNext();

    if(token == QXmlStreamReader::StartDocument)
        continue;

    if (rdr->name() == "Personalizado") {
        continue;
    }


    if(rdr->name() == "AjustesECG"){
        qDebug() << rdr->attributes().value("setting_ecg.V_on").toString();
        qDebug() << rdr->attributes().value("setting_ecg.marcapasos").toString();
        qDebug() << rdr->attributes().value("setting_ecg.alarm_on_st2").toString();
    }

}

zabdielfer

@Taz742
Thank you for spent time in my topic. :)

Taz742

@zabdielfer
Is it helpfull for you?

zabdielfer

@Taz742
yes, thank you