Moving a QGraphicsItem by using QPropertyAnimation

I am planning to move a circle in the graphics view but it doesn't work. Here is my source code:

circle.h

Code:

---

#ifndef CIRCLE_H
#define CIRCLE_H
#include <QGraphicsItem>
#include <QPainter>
 
class Circle : public QObject, public QGraphicsItem
{
    Q_OBJECT
    Q_PROPERTY(QPointF pos READ pos WRITE setPos)
public:
    Circle();
    ~Circle();
    QRectF boundingRect() const;
protected:
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
};
 
#endif // CIRCLE_H

---

dialog.h

Code:

---

#ifndef DIALOG_H
#define DIALOG_H
 
#include <QDialog>
#include <QtGui>
#include <QPropertyAnimation>
#include "circle.h"
 
namespace Ui {
class Dialog;
}
 
class Dialog : public QDialog
{
    Q_OBJECT
 
public:
    explicit Dialog(QWidget *parent = 0);
    ~Dialog();
 
private:
    Ui::Dialog *ui;
    QGraphicsScene *scene;
    Circle *circle;
    QPropertyAnimation *animation;
};
 
#endif // DIALOG_H

---

circle.cpp

Code:

---

#include "circle.h"
 
Circle::Circle()
{
 
}
 
Circle::~Circle()
{
 
}
 
QRectF Circle::boundingRect() const
{
    return QRectF(20, 100, 50, 50);
}
 
void Circle::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    QRectF rect = boundingRect();
    QPen pen(Qt::NoPen);
    QBrush brush(Qt::blue);
    brush.setStyle(Qt::SolidPattern);
 
    painter->setPen(pen);
    painter->setBrush(brush);
    painter->drawEllipse(rect);
}

---

dialog.cpp

Code:

---

#include "dialog.h"
#include "ui_dialog.h"
 
Dialog::Dialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Dialog)
{
    ui->setupUi(this);
 
    scene = new QGraphicsScene(this);
    ui->graphicsView->setScene(scene);
 
    circle = new Circle;
    scene->addItem(circle);
 
    animation = new QPropertyAnimation(circle, "geometry", NULL);
    animation->setDuration(5000);
    animation->setEndValue(QRect(500, 100, 150, 150));
 
    animation->start();
}
 
Dialog::~Dialog()
{
    delete ui;
}

---

Can anyone please tell me how to solve this thing? Thanks in advance. :D

Your property is called "pos" .
You are trying to animate non existant property "geometry"

Cheers,
_

Neither QObject nor QGraphicsItem seem to have the 'geometry' property you're assigning to that animation controller. So it's not defined anywhere, and this is probably why nothing happens.

The documentation specifies the properties of QObject-based classes:
http://doc.qt.io/qt-5/qobject.html
http://doc.qt.io/qt-5/qgraphicsitem.html

So in your case you will probably have to write something like this:

Code:

---

Q_PROPERTY(QRectF geometry READ geometry WRITE setGeometry)
 
void setGeometry( QRectF& newRect )
{
	geometry = newRect // Copy.
	setPos( newRect.topLeft() );
}
 
QRectF boundingRect()
{
	return geometry;
}

---

Also, make sure you're only using QRectF values (for example in the 'setEndValue' function).