Problem with creating dynamic library

[Nortrom]

Hi everyone. I have to make plugin system for my application. But i'm new to c++ and qt, though have some basic knowledge.
I'm trying to create a plugin and load it in my program by calling
@
QPluginLoader loader;
loader.setFileName("PolygonController.dll");
if (!loader.load())
{
qWarning( "This is not Qt plugin or plugin not match out Qt Libraries" );
qDebug() << loader.errorString();
};

QObject * qobj = qobject_cast< QObject* >( loader.instance() );
if (qobj) qWarning("its qobject");
ShapeController * controller = qobject_cast<ShapeController* > (qobj);
if ( !controller )
{
  qWarning( "its not ShapeController" );
};

@

and output is "its qobject. its not ShapeController"

I guess the problem is that i don't use interface, i use a virtual class.
@
#ifndef SHAPEController_H
#define SHAPEController_H
#include <e:/qt_progects/paint/activatebutton.h>
#include <e:/qt_progects/paint/paintscene.h>

class ShapeController: public QObject
{
Q_OBJECT
public:
virtual void keyPressed (QKeyEvent *e) = 0;
void setScene (PaintScene *scene);
void loseScene ();
bool scribbling;
QString name;
ActivateButton *activateButton;
PaintScene *scene;
public slots:
virtual void mousePressed (QGraphicsSceneMouseEvent *e) = 0;
virtual void mouseMoved (QGraphicsSceneMouseEvent *e) = 0;
virtual void mouseReleased (QGraphicsSceneMouseEvent *e) = 0;
private:
};

Q_DECLARE_INTERFACE( ShapeController,
"com.nort.ShapeController.Interface.version/1.0")

#endif // SHAPEController_H
@

Interfaces don't suit me well, because that metods - setScene and loseScene, +some fields are same for derived classes, and i need that slots in my pre-definition.

My dll goal is to override that virtual methods
@class PolygonController: public ShapeController
{
//Q_INTERFACES(ShapeController)
public:
PolygonController();
void keyPressed(QKeyEvent *e);
PolygonItem *current;
public slots:
void mousePressed (QGraphicsSceneMouseEvent *e);
void mouseMoved (QGraphicsSceneMouseEvent *e);
void mouseReleased (QGraphicsSceneMouseEvent *e);
private:

};@

so i can load all my shape controllers (i have line, ellipse, rect, polygon controllers) in run-time from dll's.

The question is what am i doing wrong, maybe there is another way to solve this?
sorry for grammatical mistakes i have made, english is not my native language

[giesbert]

What you show there is no interface, it's a class definition that also requires some implementation. Where is the class ShapeController implemented, especially the methods ShapeController::setScene etc.?

[Nortrom]

in ShapeController.cpp . This code works already, i just have to export my derived classes into dll's.

[giesbert]

So you export ShapeController from a dll that is used by the plugin and the main app? ok, so that is not the problem. Did you debug the whole thing and expand the macros for plugins / checked what loader.instance returned?

[Nortrom]

[quote author="Gerolf" date="1350482862"]So you export ShapeController from a dll that is used by the plugin and the main app?[/quote]
ShapeController is already in my main project, and i use him with #include <waytofile/shapecontroller.h> in my dll.

[quote author="Gerolf" date="1350482862"] ok, so that is not the problem. Did you debug the whole thing and expand the macros for plugins / checked what loader.instance returned?[/quote]

as i wrote before,
@
QObject * qobj = qobject_cast< QObject* >( loader.instance() );

if (qobj) qWarning("its qobject");

ShapeController * controller = qobject_cast<ShapeController* > (qobj);

if ( !controller )

{

  qWarning( "its not ShapeController" );

};@

output is "its qobject"
and "its not ShapeController"

but what do u mean by "expand the macros for plugins"?
i use that macros:
@Q_DECLARE_INTERFACE( ShapeController,

"com.nort.ShapeController.Interface.version/1.0")@

@Q_INTERFACES(ShapeController)@

@Q_EXPORT_PLUGIN2 ( polygoncontroller, PolygonController )@
which need to create correct plugin, and plugin loads correctly from dll, but it inherits only qobject