[Qt-interest] Problem customizing QSpinBox

[Malyushytsky, Alex]

As for vtable or virtual table, it is probably better than I possibly ever could explained in C++ books.
So I will leave it up to you to learn this. You probably could  at least google "vtable in C++".


As for the problem, check that apropriate moc file is created and added to the project.

Regards,
       Alex




________________________________________
From: qt-interest-bounces at trolltech.com [mailto:qt-interest-bounces at trolltech.com] On Behalf Of Judy Duncan
Sent: Monday, April 20, 2009 11:16 AM
To: qt-interest at trolltech.com
Subject: [Qt-interest] Problem customizing QSpinBox

I'm trying to sub-class a QSpinBox so that I can get a signal when editing is finished that passes the value in the spinbox along with the signal.  Following some other examples, I have:

//*** header ****
#include <QSpinBox>
class SpinBox : public QSpinBox
{
     Q_OBJECT
      public:
         SpinBox (QWidget *parent = 0);
     private slots:
          void valChange ();
    signals:
           void valueUpdate ( int value );
};

//*** implementation ****
#include "spinbox.h"
SpinBox::SpinBox(QWidget *parent)
      : QSpinBox(parent)
{
      connect (this, SIGNAL(editingFinished()),
                               this, SLOT(valChange()));
 }

void SpinBox::valChange()
{
    emit valueUpdate( this->value() );
}

I am using Designer for the mainwindow, so I put a QSpingBox on the form and then promoted it to a custom SpinBox, giving Designer the appropriate header file name.

When I build the project, I get the following link errors:
C:/DunImg/QtTest/Test2/spinbox.cpp:6: undefined reference to `vtable for SpinBox'
C:/DunImg/QtTest/Test2/spinbox.cpp:6: undefined reference to `vtable for SpinBox'
debug/spinbox.o: In function `ZN7SpinBoxC1EP7QWidget':
C:/DunImg/QtTest/Test2/spinbox.cpp:6: undefined reference to `vtable for SpinBox'
C:/DunImg/QtTest/Test2/spinbox.cpp:6: undefined reference to `vtable for SpinBox'
debug/spinbox.o: In function `ZN7SpinBox9valChangeEv':
C:/DunImg/QtTest/Test2/spinbox.cpp:13: undefined reference to `SpinBox::valueUpdate(int)'
collect2: ld returned 1 exit status


What's the vtable and why does it thing valueUpdate is undefined?

Thanks in advance,
Judy




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