Problem with connecting signals and slots with Qt (5), HELP please.

timain

Hello I have a class:
@
class AjoutDefaut: public QDialog
{
Q_OBJECT
public
...
private:

classDefaut* m_defaut;
...
private slots:
void beginProcess();
};
@

and when I connect the beginProcess() with a signal(defined in classDefaut class) in AjoutDefaut.cpp

@ connect(m_defaut, SIGNAL(goProcess()), this, SLOT(beginProcess())); @

I have this error (when I write Q_OBJECT)

AjoutDefaut.obj:-1: erreur : LNK2001: symbole externe non résolu "public: virtual struct QMetaObject const * __cdecl AjoutDefaut::metaObject(void)const " (?metaObject@AjoutDefaut@@UEBAPEBUQMetaObject@@XZ)

AjoutDefaut.obj:-1: erreur : LNK2001: symbole externe non résolu "public: virtual void * __cdecl AjoutDefaut::qt_metacast(char const *)" (?qt_metacast@AjoutDefaut@@UEAAPEAXPEBD@Z)

AjoutDefaut.obj:-1: erreur : LNK2001: symbole externe non résolu "public: virtual int __cdecl AjoutDefaut::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@AjoutDefaut@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z)

AjoutDefaut.obj:-1: erreur : LNK2001: symbole externe non résolu "public: static struct QMetaObject const AjoutDefaut::staticMetaObject" (?staticMetaObject@AjoutDefaut@@2UQMetaObject@@B)

AND, if I COMMENT "Q_OBJECT" in DefautWidget class I get this Error:

QObject::connect: No such slot QDialog::beginProcess() in AjoutDefaut.cpp:132

I don't know how to resolve this BIG PROBLEM, I have been on this since this morning

Help please

Thank you

SGaist

Hi,

When adding/removing Q_OBJECT, you need to re-run qmake before rebuilding (or rebuild from scratch).

hskoglund

Hmmm, perhaps your classDefaut class does not inherit from QObject?

timain

Hi,
Thank's for reply,
I re-runned QMake and *classDefaut * inherits from QFrame, And I use Q_OBJECT within it.

I specify that if I replace SLOT(beginProcess()) by SLOT(close()) or something else it works...

hskoglund

Ok, another guess: your AjoutDefaut class definition, is it in an .h file?

timain

Yes, it is. And I call connect(..) function at the constructor in .cpp file.

SGaist

Can you show the code from both classes ?

timain

AjoutDefaut.h

@
#ifndef AJOUTDEFAUT_H ( There is a problem here, when I copied this line it was impossible, so I had to re-write it,
this line is not written like the others #ifndef in other classes in QtCreator, it has a different color, i don't know what kind of problem it is )
#define AJOUTDEFAUT_H

class AjoutDefaut: public QDialog
{
Q_OBJECT
public:

/*

Constructeur */
AjoutDefaut();

private:

(...)
/*

Bouton pour la détection de contour /
QPushButton m_btn_cont;

/*

Widget contenant l'image de base sur laquelle on colle les défauts */
classDefaut *m_classDefaut ;

private slots:
void gaussianfilter(QImage image);
void border_detect(QImage image);
void validate();
void beginProcess();
};
#endif AJOUTDEFAUT_H @

AjoutDefaut.cpp

The constructor

@AjoutDefaut::AjoutDefaut()
{
(..)

///> Connection des boutons avec les SLOT
connect(m_classDefaut , SIGNAL(enableProcessing()), this, SLOT(beginProcess()));

(..)
}@

Slot: beginProcess()
@void AjoutDefaut::beginProcess()
{
m_btn_cont->setEnabled(true);
QImage currentImage = *(m_dragWidgetCible->m_currentAnomaly);
connect(m_btn_cont, SIGNAL(clicked()), this, SLOT(border_detect(currentImage)));
}@

timain

classDefaut.h file

@
#ifndef CLASSDEFAUT_H
#define CLASSDEFAUT_H

#include (...)

QT_BEGIN_NAMESPACE
//class QDragEnterEvent;
class QDropEvent;
class QDragMoveEvent;
class QDragMoveEvent;
QT_END_NAMESPACE

//! [0]
class classDefaut : public QFrame
{
Q_OBJECT
friend class AjoutDefaut;

public:
...

signals:
void enableProcessing();

private slots:
void border_detect(QImage image);
void loadImage(QImage image);
};
//! [0]

#endif // CLASSDEFAUT_H
@

timain

Problem fixed, I deleted AjoutDefaut.h, re-created it and include the new file with the same contain in my project (there was a problem with this file so moc object cannot be created when I use Q_OBJECT).

Thank you all