@ --Bullet.c--

Bullet::Bullet(QGraphicsItem *parent): QObject(), QGraphicsPixmapItem(parent){
// draw graphics
setPixmap(QPixmap(":/images/bullet.png"));

// make a timer to move bullet every 50ms
QTimer * timer = new QTimer(this);
connect(timer,SIGNAL(timeout()),this,SLOT(move()));

// start the timer every 50 ms
timer->start(50);

}

void Bullet::move(){
// move the bullet forward
setPos(x()-10,y());
// if the bullet is off the screen, destroy it
if (pos().x() < 0){
scene()->removeItem(this);
delete this;
}
}

//---Bullet.h
#ifndef BULLET_H
#define BULLET_H

#include <QGraphicsPixmapItem>
#include <QGraphicsItem>
#include <QObject>

class Bullet: public QObject,public QGraphicsPixmapItem {
Q_OBJECT
public:
Bullet(QGraphicsItem * parent=0);
public slots:
void move();
};

#endif // BULLET_H

@

@ main.cpp

     // create the scene
     scene = new QGraphicsScene();
     scene->setSceneRect(0,0,800,600); 
     ui->graphicsView->setScene(scene);

    // Label created
    imageLabel = new QLabel;
    imageLabel ->setBackgroundRole(QPalette::Base);

    //Bullet created
    Bullet * bullet = new Bullet();
    bullet->setPos(x(),y());
    scene()->addItem(bullet);

@