trying to use QXmlParser and friends

[mzimmers]

@Chris-Kawa OK, progress is being made. I've sub-classed the default handler, and the startElement() and endElement() methods. In my other XML parser (expat) there was also a routine handleData() which was used to get the content between the start and end tags. I don't see an equivalent to that in QXmlDefaultHandler; how do I retrieve that data?

Thanks...

[Chris Kawa]

how do I retrieve that data?

See QXmlDefaultHandler::characters().

[mzimmers]

@Chris-Kawa oh my goodness, that is a thing of beauty.

Thanks to all who helped.

EDIT: actually, I do have a follow-on question: this will allow me to build my map of tags and content. I need to export that map when I'm done. I'm thinking of making the map a member variable, and adding a method that returns it. Is there a better way to do this?

[Chris Kawa]

I'm thinking of making the map a member variable, and adding a method that returns it. Is there a better way to do this?

So an XMLTagMapMakerHandler? Sounds good to me.

[mzimmers]

Well, I shouldn't have declared victory so quickly. When I migrated my test code into my app, I got this error:

C:\wifibutton\utility\xmlparser.h:16: error: 'XmlHandler' does not name a type; did you mean 'XmlParser'?
     XmlHandler m_handler;
     ^~~~~~~~~~
     XmlParser

Here are some snippets:

class XmlHandler : public QXmlDefaultHandler
{
private:
    MsgHash m_hash;
public:
    XmlHandler();
...
}

#include "xmlhandler.h"

class XmlParser
{
    QXmlSimpleReader m_reader;
    XmlHandler m_handler;
   ...
}

Is there something special I need to know about sub-classing QXmlDefaultHandler, or am I just brain-fading here?

Thanks...

[mrjj]

@mzimmers
Just to be sure its not that.
Does xmlparser.h include XmlHandler.h and reverse ?
(circular include)

[mzimmers]

@mrjj no. xmlparser.h includes xmlhandler.h, but not the other way around.

[mrjj]

@mzimmers
Ok, just had to be sure :)

It simply says it don't know type so it don't see the include for some reason.

Did you try clean all, rebuild ?

[mzimmers]

Yes, I did.

Here's the complete code from the headers:

xmlhandler.h

#ifndef XMLHANDLER_H
#define XMLHANDLER_H


#include <QXmlDefaultHandler>

#include "message.h"

using namespace std;

class XmlHandler : public QXmlDefaultHandler
{
private:
    MsgHash m_hash;
    bool m_tagStarted = false;
    QString m_tag;
    QString m_data;
    QXmlInputSource *m_source;

public:
    XmlHandler();
    ~XmlHandler();
    bool startElement(const QString &uri,
                      const QString &local,
                      const QString &name,
                      const QXmlAttributes &atts) override;
    bool endElement(const QString &uri,
                      const QString &local,
                      const QString &name) override;
    bool characters(const QString &ch) override;
    void getHash(MsgHash &msgHash) {msgHash = m_hash;}
};


#endif // XMLHANDLER_H

xmlparser.h:

#ifndef XMLPARSER_H
#define XMLPARSER_H

#include <stdint.h>

#include <QXmlDefaultHandler>
#include <QXmlSimpleReader>

#include "constants.h"
#include "message.h"
#include "xmlhandler.h"

class XmlParser
{
    QXmlSimpleReader m_reader;
    XmlHandler m_handler;
public:
    XmlParser();
    ~XmlParser();
    int process(string xml, MsgHash &msgHash);
};

#endif // XMLPARSER_H

[mrjj]

Hi
It looks ok.
Could you try add some dummy class to the xmlhandler.h

class Test {
};

and see if it can see that symbol ?

just to test it dont see the include and not something with class XmlHandler

[mzimmers]

@mrjj good test -- it didn't see that either. I wonder if XMLHANDLER_H is a reserved term...?

ANSWER: no it isn't...

[mrjj]

@mzimmers

Hmm can you check your .pro file its not listed 2 times ?

Also
can you please inspect both files
with Include Hierarchy?

The last.

and see if you see anything odd.

[mzimmers]

@mrjj that wasn't it exactly, but you put me on the right track. I'll report back in a bit.

Thanks...

[mzimmers]

@mrjj great suggestion there! Long story short, I had a cyclic dependency. Thanks for your help on this.

[mrjj]

Super :)
Well it's my number one suspect when it says "don't know symbol"
and you check you have the header included and all seem fine.