Error: No rule to make target `kio_afc.moc', needed by `kio_afc.o'.

Hello Sir,
I am try to build kio_afc in Qt creater on Ubuntu.But it gives error No rule to make target `kio_afc.moc', needed by`kio_afc.o'.I have both file kio_afc.h and kio_afc.cpp. I can't understand what is the cause of this error please help me if you have any idea
