Subclassing QLabel

[Maluko_Da_Tola]

Hi,

I am trying to sublass QLabel to create a label capable of handling mouse click events. The following code works fine:

#include <QtGui>
 
class MyLabel : public QLabel
{
   Q_OBJECT
public:
protected:
   virtual void mousePressEvent(QMouseEvent *event)
   {
   if (event->button()==Qt::LeftButton)
   {
   qWarning() << Q_FUNC_INFO;
   }
   }
};
 
 
#include "main.moc"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
MyLabel l;
l.setText("foo bar");
l.show();
return app.exec();
}

#include <QtGui>

class MyLabel : public QLabel
{
   Q_OBJECT
public:
protected:
   virtual void mousePressEvent(QMouseEvent *event)
   {
   if (event->button()==Qt::LeftButton)
   {
   qWarning() << Q_FUNC_INFO;
   }
   }
};


#include "main.moc"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
MyLabel l;
l.setText("foo bar");
l.show();
return app.exec();
}

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What I don't understand is, when I try to define MyLabel class in a seperate header file, Qt does not compile anymore! Why is this happening?

Thank you

[norobro]

What errors do you get?

You don't need to "#include main.moc" if you have the class in a separate file.

[Urthas]

Really, you ought not to define functions in header files. You can, but inline functions are normally reserved for very short functions, such as one-line "getters" or "setters" (although they in turn raise interesting OO-design questions). Your function is small, but best to form good habits now. In addition, most of the time, event-handling code should propagate the event after you do your custom work by including a call to the parent class code, as follows (for this case):

...
QLabel::mousePressEvent(event);
} // end function

...
QLabel::mousePressEvent(event);
} // end function

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This may or may not be what you want but is *usually* appropriate.