Qt Create a scene with a grid of individual rectangles - c++

Question

I want to create a grid of 22x22 individual rectangles. I will be filling each rectangle with a colour based on a predefined colour scale.
At the moment my header file looks like this:
#ifndef DIALOG_H
#define DIALOG_H
#include <QDialog>
#include <QtGui>
#include <QtCore>
#include <QGraphicsScene>
#define GRIDDIM 22
namespace Ui {
class Dialog;
}
class Dialog : public QDialog
{
Q_OBJECT
public:
explicit Dialog(QWidget *parent = 0);
~Dialog();
private:
Ui::Dialog *ui;
QGraphicsScene *scene;
QGraphicsRectItem *rec[GRIDDIM*GRIDDIM];
protected:
void paintEvent(QPaintEvent *e);
};
#endif // DIALOG_H
So I have declared 22x22 individual rectangle objects in the rec[] array.
My .cpp file looks like this:
#include "dialog.h"
#include "ui_dialog.h"
#include <QGraphicsView>
Dialog::Dialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::Dialog)
{
ui->setupUi(this);
scene = new QGraphicsScene(this);
//rec = new QGraphicsRectItem;
ui->graphicsView->setScene(scene);
QBrush redBrush(Qt::red);
QBrush blueBrush(Qt::blue);
QPen blackPen(Qt::black);
QPen bluePen(Qt::blue);
blackPen.setWidth(0);
bluePen.setWidth(0);
int height = 15;
int width = 15;
int xpos = 0;
int ypos = 0;
for (int i=0;i<GRIDDIM;i++){
for(int j=0;j<GRIDDIM;j++){
scene->addRect(i*(width),j*(height),width,height,blackPen);
}
}
But this is just assigning the generic rect object by using addrect.
Is it possible to implement my rec[] array into the scene so that I can then say for example set rec[10] blue?
Using:
QGraphicsRectItem *rec = new QGraphicsRectItem(QRect(xpos,ypos,width,height));
Gives back an error:
allocation of incomplete type 'QGraphicsRectItem'
forward declaration of 'QGraphicsRectItem'