Undefined reference to QAbstractListModel::postion - qt

Question

I'm getting this error when implementing QAbstractListModel.
./debug\moc_ObjectModel.o:moc_ObjectModel.cpp:(.rdata$_ZTV12ObjectModel[__ZTV12ObjectModel]+0x38): undefined reference to `QAbstractListModel::position(int, int, QModelIndex const&) const'
collect2.exe: error: ld returned 1 exit status
Building the project was successful before I add insert and remove method to my model.
First, I add the insert and remove method but forgot to call begin* and end* method, so I got an error when rebuilding the project.
After that, I add begin* and end* as stated in the docs. But, when I build the project, I'm getting the error stated above. Then, I remove the insert and remove method and the error still remains.
I have tried to delete the build directory of the project, clean, run qmake, and then build the project but it was no good.
ObjectModel.h
#ifndef OBJECTMODEL_H
#define OBJECTMODEL_H
#include "ProjectCoreGlobal.h"
#include "Data/MyObject.h"
#include <QAbstractListModel>
class PROJECTCORESHARED_EXPORT ObjectModel : public QAbstractListModel
{
Q_OBJECT
public:
explicit ObjectModel(QObject *parent = 0);
int rowCount(const QModelIndex &parent) const Q_DECL_OVERRIDE;
QVariant data(const QModelIndex &position, int role) const Q_DECL_OVERRIDE;
// void insertObject(MyObject *object);
// void removeObject(int position);
MyObjectList objects() const;
MyObject *objectById(const int &id);
MyObject *objectByName(const QString &name);
private:
MyObjectList mObjects;
};
#endif // OBJECTMODEL_H
ObjectModel.cpp
#include "ObjectModel.h"
ObjectModel::ObjectModel(QObject *parent) :
QAbstractListModel(parent)
{
}
int ObjectModel::rowCount(const QModelIndex &parent) const
{
if (parent.isValid())
return 0;
else
return mObjects.size();
}
QVariant ObjectModel::data(const QModelIndex &index, int role) const
{
if (!index.isValid())
return QVariant();
MyObject *obj = mObjects.at(index.row());
if (role == Qt::DisplayRole) {
return obj->name();
}
return QVariant();
}
// void ObjectModel::insertObject(MyObject *object)
// {
// beginInsertRows(QModelIndex(), mObjects.count(), mObjects.count());
// mObjects.append(object);
// endInsertRows();
// }
// void ObjectModel::removeObject(int position)
// {
// beginRemoveRows(QModelIndex(), position, position);
// mObjects.removeAt(position);
// endRemoveRows();
// }
MyObjectList ObjectModel::objects() const
{
return mObjects;
}
MyObject *ObjectModel::objectById(const int &id)
{
foreach (MyObject *obj, mObjects)
{
if (obj->id() == id)
{
return obj;
}
}
return NULL;
}
MyObject *ObjectModel::objectByNme(const QString &name)
{
foreach (MyObject *obj, mObjects)
{
if (obj->name() == name)
{
return object;
}
}
return NULL;
}

Answer 1

The only QAbstractListModel class member that matches the signature from the error message is QAbstractListModel::index.
It most certainly means that there is a #define index position somewhere before the include for that class, either in the 2 headers files, or in the project settings (DEFINES += index=position in the .pro file).
Try putting #include <QAbstractListModel> first in ObjectModel.h.
You should also check that the Qt header file for the QAbstractListModel class wasn't inadvertently modified by a search/replace in the wrong window (compare with the original class here).