Problems animating QGraphicsProxyWidget

Hi All,

I'm trying to animate a push button I have in my scene.
I want the button to become visible with an animation when the mouse enters the scene (essentially gradually changing the opacity of the button from 0 to 1)

The QPropertyAnimation class seems to be exactly what I need but it is not working with QGraphicsProxyWidget.
This is the way I'm creating the button when I initialize the interface of the QGraphicsView

Code:

---

void MyQGraphicsView::buildInterface(){
    ....
    myButton = new QPushButton(this);    // myButton  member QPushButton variable
    myButtonProxy = scene()->addWidget(myButton);    // myButtonProxy  member QGraphicsProxyWidget variable
    ...
}
 
void MyQGraphicsView::enterEvent( QEvent * )
{
    QPropertyAnimation *animation = new QPropertyAnimation(myButtonProxy, "opacity");
    animation->setDuration(1000);
 
    animation->setStartValue(0);
    animation->setEndValue(1);
 
    animation->start(QAbstractAnimation::DeleteWhenStopped);
}

---

The animation has no effect on the opacity of the button. I also tried for test to modify with an animation the position of the button. Well If I create the QPropertyAnimation using the proxy widget then the animation is not working, if I create it using the button itsself then the animation is working (see example below)

Code:

---

void MyQGraphicsView::enterEvent( QEvent * )
{
    // QPropertyAnimation *animation = new QPropertyAnimation(myButtonProxy, "pos");    // DOES NOT WORK
    QPropertyAnimation *animation = new QPropertyAnimation(myButton, "pos");
    animation->setDuration(1000);
 
    animation->setStartValue(QPointF(0,0));
    animation->setEndValue(QPointF(scene()->width()/2, scene()->height()/2));
 
    animation->start(QAbstractAnimation::DeleteWhenStopped);
}

---

I'm using Qt 4.7.3
Do you have any idea how to fix this issue?

Thanks in advance,
Calogero

Try using the windowOpacity property of the QPushButton instead of the opacity property of the QGraphicsProxyWidget.

d_stranz thanks for your reply.

I already tried that property but it is not working. As far as I understand that property can only be used for top level widgets.

---

Added after 1 41 minutes:

I could fix the problem.
I do not need to pass a parent to the QPushButton when creating it.