qt: How to animate the transparency of a QDeclarativeView using QPropertyAnimation? - qt

Question

I want to use QPropertyAnimation to animate the transparency of a QDeclarativeView .But,it doesn't work.It's nothing to change and no errors, but I use property "geometry",it works.I have no ideas.
Here is my main.cpp code:
int main(int argc, char *argv[])
{
QApplication a(argc, argv, true);
QDeclarativeView* view;
QDeclarativeContext *context;
QDeclarativeEngine* engine;
Connector* connector;
view = new QDeclarativeView();
connector = new Connector();
context = view->rootContext();
context->setContextProperty("Connector", connector);
context->setContextProperty("gRadioQMLDir", QDir::currentPath());
view->setSource(QUrl::fromLocalFile("qml/Main.qml"));
view->setViewportUpdateMode(QGraphicsView::MinimalViewportUpdate);
view->show();
QPropertyAnimation animation(view, "windowOpacity");
animation.setDuration(30000);
animation.setStartValue(0.0);
animation.setEndValue(1.0);
animation.start();
return a.exec();
}

Answer 1

Try to animate widget with using QGraphicsOpacityEffect. Sample:
#include <QApplication>
#include <QWidget>
#include <QDeclarativeView>
#include <QGraphicsOpacityEffect>
#include <QPropertyAnimation>
#include <QPushButton>
int main( int argc, char *argv[] )
{
QApplication a( argc, argv );
QWidget w;
QGraphicsOpacityEffect *opacity = new QGraphicsOpacityEffect;
QPropertyAnimation *anim = new QPropertyAnimation( opacity, "opacity" );
//QDeclarativeView *dv = new QDeclarativeView( &w );
//dv->setFixedSize( 200, 200 );
//dv->setGraphicsEffect( opacity );
QPushButton *btn = new QPushButton( "Button", &w );
btn->setGraphicsEffect( opacity );
anim->setDuration( 2000 );
anim->setStartValue( 0.1 );
anim->setEndValue( 1.0 );
anim->setEasingCurve( QEasingCurve::InCubic );
anim->start();
w.setFixedSize( 300, 200 );
w.show();
return a.exec();
}
Note: "windowOpacity" property is valid only for widgets that are windows.