slot issue

[stef13013]

Hi guys,

Could you tell me why the "about" messagebox doesn't trigger whe I'm doing this :

class Main: public QMainWindow
{
	//Q_OBJECT
 
public:
	Main();
 
public slots:
	void about();
 
private:
	QToolBar *m_tb;
	QMenu *m_settings;
	void createMenubar();
};
 
 
void Main::about()
{
	QMessageBox::about( this, tr("About"), tr("test") );
}
 
 
 
void Main::createMenubar()
{
	QMenu *menu;
	QAction *atTop;
 
	atTop = new QAction("Always on top", this);
	connect(atTop, SIGNAL(triggered()), this, SLOT(about()));
 
	menu = menuBar()->addMenu(tr("&Settings"));
	menu->addAction(atTop);
}
 
 
 
Main::Main(): QMainWindow()
{
	createMenubar();
}
 
 
 
int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
 
	Main *w = new Main();
	w->show();
	return a.exec();
}

class Main: public QMainWindow
{
	//Q_OBJECT

public:
	Main();

public slots:
	void about();

private:
	QToolBar *m_tb;
	QMenu *m_settings;
	void createMenubar();
};


void Main::about()
{
	QMessageBox::about( this, tr("About"), tr("test") );
}



void Main::createMenubar()
{
	QMenu *menu;
	QAction *atTop;

	atTop = new QAction("Always on top", this);
	connect(atTop, SIGNAL(triggered()), this, SLOT(about()));

	menu = menuBar()->addMenu(tr("&Settings"));
	menu->addAction(atTop);
}



Main::Main(): QMainWindow()
{
	createMenubar();
}



int main(int argc, char *argv[])
{
	QApplication a(argc, argv);

	Main *w = new Main();
	w->show();
	return a.exec();
}

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I cannot find my fault

Thanks for your help

[wysota]

Q_OBJECT macro is commented out.

[stef13013]

Yes, thanks, I did that to avoid the message :
undefined reference to `vtable for Main'

I guess it's a probem with MOC...

[Zlatomir]

I guess you write all that code in one file?
If so write this at the end (after your code):

//...
#include "main.moc"

//...
#include "main.moc"

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Then run Clean All from the Build menu in Qt Creator, and it should run and build (without undefined vtable)

But it's better if you learn the C++ way of writing classes: a .h for declaration and a .cpp file for the implementation (and in that way you don't need to include the file that moc generate for you)

[stef13013]

Indeed, it was just a "quick and dirty little test"

By the way, you're right Zlatomir, thanks for your answer and advice...