Question

I am trying to extend QLine class to include a color attribute. I used QCreator to create the code for the new class QLineColor and I just added the attribute char color=0 in the public data. Here is the code generated by QCreator.

UPDATE: Modified according to response about QObject. but now I am getting some other errors:

/home/james/qtsdk-2010.05/qt/include/QtCore/qobject.h:309: error:
 ‘QObject::QObject(const QObject&)’ is private
within this context
and it lists several qt/include directories

File:QLineColor.h

#ifndef QLINECOLOR_H
#define QLINECOLOR_H

#include <QLine>
#include <QObject>

class QLineColor : public QObject, public QLine
{
    Q_OBJECT
public:
    explicit QLineColor(int x1, int y1, int x2, int y2, char color);
    char color;


};

#endif // QLINECOLOR_H

File:qlinecolor.cpp

#include "qlinecolor.h"

QLineColor::QLineColor(int x1, int y1, int x2, int y2, char color) :
    QLine(x1, y1, x2, y2)
{
    color = 0;
}

Answer 1

QLine doesn’t derive from QObject. Therefore Q_OBJECT etc. are all undefined.

#include <QLine>
class QLineColor : public QLine
{
    QLineColor();
    char color;
};

should work.