[Solved] Animate QGraphicsWidget by change of position.

idlefrog

This must be an easy one, but for some reason I can't animate my Widget.

So a snippet of my widget code is:

@class RoundedBox : public QGraphicsWidget
{
Q_PROPERTY( QPointF pos READ pos WRITE setPos )

public:

RoundedBox(QGraphicsWidget *parent = 0);

QPointF pos() const{ return QGraphicsObject::pos(); } // don't really need these - just for debug
void setPos( QPointF& pos ) { QGraphicsObject::setPos( pos ); }

...
};@

And in my main window
I have:

@void MainWindow::animate()
{

QPropertyAnimation animation(_rounded_box, "pos"); // just change position
animation.setDuration(10000);
animation.setStartValue(QPointF(0, 0));
animation.setEndValue(QPointF(100, 30));

animation.start();

}@

Now the RoundedBox widget has been added to the scene, and is visible, but does not move when 'animate' is called.
Am I doing something rather silly here???

mcosta

Hi,

are you really defining "pos" property?
If yes, you're overriding default property.

Try to remove PROPERTY and methods pos() and setPos().

idlefrog

Well, I put that 'pos' property in there just to see if 'setPos' was ever called. Sadly it is never called. But I fail to see why.

idlefrog

Following the documentation I even tried to animate this object in the graphics scene:

@class MyGraphicsRectItem : public QObject, public QGraphicsRectItem
{
Q_OBJECT
Q_PROPERTY(QRectF geometry READ geometry WRITE setGeometry)
Q_PROPERTY(QPointF pos READ pos WRITE setPos)

public:
explicit MyGraphicsRectItem(QGraphicsRectItem* parent=0):QGraphicsRectItem(parent){}
explicit MyGraphicsRectItem(qreal x, qreal y, qreal w, qreal h, QGraphicsItem *parent = 0):QGraphicsRectItem(x,y,w,h,parent){}

QRectF geometry(){ return rect() ;}
void setGeometry( QRectF& r){ setRect(r);}

};@

If I just set the position manually in the 'animate' method the item moves... but the animation itself never happens. And there are no error messages either, such as a missing property, or setter/getter etc... :(

SGaist

Hi,

Your QPropertyAnimation goes out of scope at the end of your animate function hence it doesn't run.

@
QPropertyAnimation *animation = new QPropertyAnimation(_rounded_box, "pos"); // just change position
animation->setDuration(10000);
animation->setStartValue(QPointF(0, 0));
animation->setEndValue(QPointF(100, 30));

animation->start(QAbstractAnimation::DeleteWhenStopped);

@

If you run your animation more than once, consider making it a member of your MainWindow class so you don't have to recreate it each time animate() is called

Hope it helps

idlefrog

Oh yes!...Thank you very much! :) Greatly appreciated :)
The above code worked :)

SGaist

You're welcome !

Please update the thread's title to solved so other people will know that this issue has a solution.