I am unable to connect qdbus screensaver ActiveChanged() signal for Ubuntu,but following code works well in Fedora.
QDBusConnection sessionConnection=QDBusConnection::sessionBus();
sessionConnection.connect("org.freedesktop.ScreenSaver","/org/freedesktop/ScreenSaver","org.freedesktop.ScreenSaver","ActiveChanged",this,SLOT(handleScreenSaverActiveChanged(bool)));
but gnome's Screensaver is connected and work in ubuntu as i want.
sessionConnection.connect("org.gnome.ScreenSaver","/org/gnome/ScreenSaver","org.gnome.ScreenSaver","ActiveChanged",this,SLOT(handleScreenSaverActive(bool)));
Is there any other generic signals which works in all desktop Environment. Thanks