Problem when adding XML support

[Shawn]

I want to add XML support to my project. I write like this:

in "paser.h"

#ifndef PASER_H
#define PASER_H
#include <QXmlDefaultHandler>
 
class paser : public QXmlDefaultHandler
{
	Q_OBJECT
 
public:
	paser(QObject *parent);
	~paser();
 
private:
 
};
 
#endif // PASER_H

#ifndef PASER_H
#define PASER_H
#include <QXmlDefaultHandler>

class paser : public QXmlDefaultHandler
{
	Q_OBJECT

public:
	paser(QObject *parent);
	~paser();

private:
	
};

#endif // PASER_H

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in "paser.cpp"

#include "paser.h"
 
paser::paser(QObject *parent)
	: QXmlDefaultHandler(parent)
{
 
}
 
paser::~paser()
{
 
}

#include "paser.h"

paser::paser(QObject *parent)
	: QXmlDefaultHandler(parent)
{

}

paser::~paser()
{

}

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then the orror occurs:

error C2664: 'QXmlDefaultHandler::QXmlDefaultHandler(const QXmlDefaultHandler &)' : cannot convert parameter 1 from 'QObject *' to 'const QXmlDefaultHandler &'
Reason: cannot convert from 'QObject *' to 'const QXmlDefaultHandler'

error C2664: 'QXmlDefaultHandler::QXmlDefaultHandler(const QXmlDefaultHandler &)' : cannot convert parameter 1 from 'QObject *' to 'const QXmlDefaultHandler &'
Reason: cannot convert from 'QObject *' to 'const QXmlDefaultHandler'

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[marcel]

QXmlDefaultHandler does not have any constructor that takes a QObject* as parameter.
It has a copy constructor.

Anyway, this class is not a subclass of QObject, so you shouldn't do any parenting.
If you really need it, add a QObject* member to your class, and store the parent in this member.

Do this:

paser::paser(QObject *parent)
    : QXmlDefaultHandler()

paser::paser(QObject *parent)
    : QXmlDefaultHandler()

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and it will work.

Regards

[Shawn]

Marcel:
I did it like u suggested above.
But still error occurs:

>moc_paser.cpp
1>.\GeneratedFiles\Debug\moc_paser.cpp(37) : error C2039: 'staticMetaObject' : is not a member of 'QXmlDefaultHandler'
1>        c:\qt\4.2.3\include\qtxml\qxml.h(351) : see declaration of 'QXmlDefaultHandler'
1>.\GeneratedFiles\Debug\moc_paser.cpp(51) : error C2039: 'qt_metacast' : is not a member of 'QXmlDefaultHandler'
1>        c:\qt\4.2.3\include\qtxml\qxml.h(351) : see declaration of 'QXmlDefaultHandler'
1>.\GeneratedFiles\Debug\moc_paser.cpp(56) : error C2039: 'qt_metacall' : is not a member of 'QXmlDefaultHandler'
1>        c:\qt\4.2.3\include\qtxml\qxml.h(351) : see declaration of 'QXmlDefaultHandler'

>moc_paser.cpp
1>.\GeneratedFiles\Debug\moc_paser.cpp(37) : error C2039: 'staticMetaObject' : is not a member of 'QXmlDefaultHandler'
1>        c:\qt\4.2.3\include\qtxml\qxml.h(351) : see declaration of 'QXmlDefaultHandler'
1>.\GeneratedFiles\Debug\moc_paser.cpp(51) : error C2039: 'qt_metacast' : is not a member of 'QXmlDefaultHandler'
1>        c:\qt\4.2.3\include\qtxml\qxml.h(351) : see declaration of 'QXmlDefaultHandler'
1>.\GeneratedFiles\Debug\moc_paser.cpp(56) : error C2039: 'qt_metacall' : is not a member of 'QXmlDefaultHandler'
1>        c:\qt\4.2.3\include\qtxml\qxml.h(351) : see declaration of 'QXmlDefaultHandler'

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[wysota]

Remove the Q_OBJECT macro. The handler is not a QObject! Don't treat it like one.

[Shawn]

wysota
Thanks a lot!
but when I write like this in paser.cpp

public:
	Paser(QObject *parent);
	~Paser();
    bool startElement(const QString &namespaceURI,
                      const QString &localName,
                      const QString &qName,
                      const QXmlAttributes &attributes);

public:
	Paser(QObject *parent);
	~Paser();
    bool startElement(const QString &namespaceURI,
                      const QString &localName,
                      const QString &qName,
                      const QXmlAttributes &attributes);

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errors again:

paser.obj : error LNK2001: unresolved external symbol "public: virtual bool __thiscall Paser::startElement(class QString const &,class QString const &,class QString const &,class QXmlAttributes const &)" (?startElement@Paser@@UAE_NABVQString@@00ABVQXmlAttributes@@@Z)

paser.obj : error LNK2001: unresolved external symbol "public: virtual bool __thiscall Paser::startElement(class QString const &,class QString const &,class QString const &,class QXmlAttributes const &)" (?startElement@Paser@@UAE_NABVQString@@00ABVQXmlAttributes@@@Z)

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[Shawn]

I got two classes: one inherited from QXmlDefaultHandler, the other from QMainWindow, like this:

class Paser : public QXmlDefaultHandler{....}
class SLD : public QMainWindow{....}

class Paser : public QXmlDefaultHandler{....}
class SLD : public QMainWindow{....}

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while class SLD is in charge of drawing image at given position (x,y,w,h);
class Paser is in charge of XML pasering using SAX, and I want it can emit signals if certain tags appear.

How I supposed to do this?
Thank u very much for helping!

[wysota]

Did you implement that method?

[Shawn]

Yes, I finally found the Qt4 Class Chart, then I noticed that it's not a QObject.

[wysota]

I'm asking about startElement()

[Shawn]

Ahh, Thank you very much
After implement startElement(), I succeed!