Как нарисовать прямоугольник в Qgraphicsview динамически (во время выполнения), используя Qt4

используя QT Creator версии 2.4.1.

Я только начинающий на платформе QT и пытаюсь нарисовать прямоугольник динамически. Программа использует 3 события мыши, а именно

• mousePressEvent
• mouseMoveEvent
• mouseReleaseEvent

Проблемы это mouseMoveEvent никогда не называется.

Вот фрагмент кода

main.cpp

#include <QtGui/QApplication>
#include "dialog.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Dialog w;
w.show();

return a.exec();
}

dialog.cpp

#include "dialog.h"#include "ui_dialog.h"#include "mysquare.h"
Dialog::Dialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::Dialog)
{
ui->setupUi(this);
setMouseTracking(true);
scene = new QGraphicsScene(this);
ui->graphicsView->setScene(scene);
scene->setBackgroundBrush(Qt::black);
square = new mySquare;
scene->addItem(square);
square->mPix = QPixmap(200,200);
square->mPix.fill(Qt::white);
scene->addPixmap(square->mPix);
}

Dialog::~Dialog()
{
delete ui;
}

void Dialog::on_pushButton_clicked()
{
square->selectedTool = 1;
}

dialog.h

#ifndef DIALOG_H
#define DIALOG_H

#include <QDialog>
#include <QtCore>
#include <QtGui>
#include "mysquare.h"
namespace Ui {
class Dialog;
}

class Dialog : public QDialog
{
Q_OBJECT

public:
explicit Dialog(QWidget *parent = 0);
~Dialog();

private slots:
void on_pushButton_clicked();

private:
Ui::Dialog *ui;
QGraphicsScene *scene;
mySquare *square;

};

#endif // DIALOG_H

mysquare.cpp

#include "mysquare.h"
using namespace std;mySquare::mySquare()
{
pressed  = false;
selectedTool = 1;
mPix = QPixmap(200,200);
mPix.fill(Qt::white);
}

void mySquare::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
painter->begin(this);
if(pressed)
{
painter->drawPixmap(0,0,mPix);
painter->drawRect(mRect);
drawStarted = true;
}
else if (drawStarted)
{
QPainter tempPainter(&mPix);
tempPainter.drawRect(mRect);
painter->drawPixmap(0,0,mPix);
}

painter->end();
}

void mySquare::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
pressed = true;

y = event->pos();
cout<<"Pos X : "<<y.x() <<endl;
cout<<"Pos Y : "<<y.y() <<endl;

if(selectedTool == 1)
{
mRect.setTopLeft(event->pos());
mRect.setBottomRight(event->pos());

cout << "Value of x_start axis " << X_1 <<endl;
cout << "Value of y_start axis " << Y_1 <<endl;
}
else if (selectedTool == 2)
{

}
update();
}

void mySquare::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
cout<<"Inside mouseMoveEvent \n";
if(event->type() == QEvent::MouseMove)
{
if(selectedTool == 1){
mRect.setBottomRight(event->pos());
}
else if (selectedTool == 2){
//mLine.setP2(event->pos());
}
}
update();
}

void mySquare::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
pressed = false;
update();
cout<<"Inside mouseReleaseEvent \n";
}

mysquare.h

#ifndef MYSQUARE_H
#define MYSQUARE_H

#include <QPainter>
#include <QGraphicsItem>
#include <QDebug>
#include <QPainter>
#include <iostream>
#include <QPixmap>
#include <QPaintEvent>
#include <QGraphicsSceneMouseEvent>

class mySquare: public QGraphicsItem
{
public:
mySquare();
int selectedTool;
QPixmap mPix;
QRectF boundingRect() const;
void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
bool pressed;
bool drawStarted;

protected:
void mousePressEvent(QGraphicsSceneMouseEvent *event);
void mouseMoveEvent(QGraphicsSceneMouseEvent *event);
void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);

private:
QRectF mRect;
QPointF y;private slots:

};

#endif // MYSQUARE_H

Пожалуйста, ведите меня,
Благодарю.