Problem in animation of progressbar in QT

i did progress bar in QT, i used both in emulator and mobile.. the infinite progress bar in appearing but its not getting animated.. (infinite progress is not coming)

here is the code which i hv written

QApplication a(argc, argv);

QProgressDialog *dialog = new QProgressDialog();

dialog->setMinimum(0);
dialog->setMaximum(0);

dialog->show开发者_如何学CMaximized(); 
dialog->exec();   
return a.exec();

pls suggest if some thing wrong

I tried this on a blank project with QTCreator and Qt 4.6.1 and it worked...

Maybe you could try to add this line : qApp->processEvents();

Hope it helps a bit!

Edit : And if you try to remove the line dialog->exec(); I don't think it's necessary...