Problems animating QGraphicsProxyWidget

[kalos80]

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);
}

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);
}

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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);
}

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);
}

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

Thanks in advance,
Calogero

[d_stranz]

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

[kalos80]

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.

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Added after 1 41 minutes:

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