Necessitas 0.3 - Android 2.2 (Dell Streak), also reported from Motorola Defy - Widget application (QMainWindow).
After using "Home" device key to pause Qt app and resuming by touching the icon again, the screen is black. Touching (invisible) action widgets will partly redraw the screen.
My (really "dirty") solution went into the plugin/platform/android code; I added a line in "androidjnimain.cpp", method "updateWindow":
------- if(!m_androidGraphicsSystem || !qApp) return; + m_androidGraphicsSystem->getPrimaryScreen()->setDirty( + m_androidGraphicsSystem->getPrimaryScreen()->geometry() ); + foreach(QWidget * w, qApp->topLevelWidgets()) w->update(); -------
There may be better solutions, but this line did the trick.