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kalos80
27th August 2012, 10:27
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


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)


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

d_stranz
27th August 2012, 22:06
Try using the windowOpacity property of the QPushButton instead of the opacity property of the QGraphicsProxyWidget.

kalos80
28th August 2012, 10:49
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.