I am fairly new to Qt and creating a simple application that initializes a number of custom QGraphicsItems in a custom QGraphicsScene. Each item is initialized with a random start position and a Weight value which is dependent on the position of the item. On a mouse move event, i want the Weight value of the items to update based on the position of the mouse cursor

I think my the mouseMoveEvent is not recognized within the graphicsScene, it seems to work fine in the main window where i implemented a label in the status bar to show the number of mouseMoveEvents and the X-Y position of the mouseMoveEvent

Here is the code:

Custom graphics Scene .h:

class ParticleScene : public QGraphicsScene { public: ParticleScene(); protected: void mouseMoveEvent(QGraphicsSceneMouseEvent *event); private: qreal WTotal; Particle *particle; }

Custom Graphics Scene .cpp:

ParticleScene::ParticleScene() { //this->setBackgroundBrush(Qt::gray); this->setSceneRect(0,0,500,500); WTotal=0; int ParticleCount =5; for (int i =0; i<ParticleCount; i++) { particle= new Particle(); particle->StartX= rand()%500; particle->StartY= rand()%500; particle->W= qSqrt(qPow(particle->StartX,2) + qPow(particle->StartY,2)); particle->setPos(particle->StartX,particle->StartY); this->addItem(particle); particle->setFocus(); WTotal+=particle->W; } } void ParticleScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event) { update(); QGraphicsScene::mouseMoveEvent(event); }

Particle.h:

I added the Keypress event function and this moved only the last item that was added to the scene, i assume only one item can get focus. The mouseMove event on the other hand didn't do anything

class Particle :public QGraphicsItem { public: Particle(); QRectF boundingRect() const; void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget); int StartX; int StartY; qreal W; protected: //added keyPressEvent to test virtual void keyPressEvent(QKeyEvent *event); virtual void mouseMoveEvent(QGraphicsSceneMouseEvent *event); };

Particle.cpp:

Particle::Particle() { // setFlag(ItemIsMovable); setFlag(ItemIsFocusable); } QRectF Particle::boundingRect() const { return QRect(0,0,120,30); } void Particle::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) { QRectF rec= boundingRect(); QBrush Brush(Qt::white); painter->fillRect(rec,Brush); painter->drawText(15,15,"Weight: "+QString::number(W)); painter->drawRect(rec); } void Particle::keyPressEvent(QKeyEvent *event) { switch(event->key()){ case Qt::Key_Right:{ moveBy(30,0); break;} case Qt::Key_Left:{ moveBy(-30,0); break;} case Qt::Key_Up:{ moveBy(0,-30); break;} case Qt::Key_Down:{ moveBy(0,30); break;} } update(); } void Particle::mouseMoveEvent(QGraphicsSceneMouseEvent *event) { this->W= this->W / qSqrt(qPow(event->pos().x(),2) + qPow(event->pos().y(),2)); moveBy(30,0); update(); }

MainWindow .h and cpp: the status bar label here displays the mouse coordinates correctly i.e. mouseMoveEvent functions here

namespace Ui { class MainWindow; } class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); ~MainWindow(); void mouseMoveEvent(QMouseEvent *event); protected: private: Ui::MainWindow *ui; ParticleScene *scene; QLabel *statlabel; int moves; }; MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); statlabel=new QLabel(this); ui->statusBar->addWidget(statlabel); statlabel->setText ("Mouse Coordinates"); setCentralWidget(ui->graphicsView); centralWidget()->setAttribute(Qt::WA_TransparentForMouseEvents); ui->graphicsView->setMouseTracking(true); scene= new ParticleScene(); ui->graphicsView->setScene(scene); ui->graphicsView->setRenderHint(QPainter::Antialiasing); moves=0; } MainWindow::~MainWindow() { delete ui; } void MainWindow::mouseMoveEvent(QMouseEvent *event) { moves+=1; statlabel->setText("MouseMoves " +QString::number(moves)+ " X:"+QString::number(event->pos().x())+"-- Y:"+QString::number(event->pos().y())); }

What am I missing in the program that causes the mousemoveevent to not function and Is there a way to focus all the items together? Would i need to perhaps, make them into QList?

In the Next step of the program, I would like the items to update their weight value based on the sum of all their weights and also move based on an algorithm that uses the new weight value to determine a new position.