The website (see below) gives you all the information for getting to the cruise terminal from the airport in Barcelona. It shows a map, and the different modes of transportation available.
I don't recommend taking public (bus) transportation. Use private conveyance (taxi etc.) for a more secure ride for you, your family, and your baggage
http://www.barcelona-tourist-guide.com/en/transport/barcelona-cruise-port.html
I don't recommend taking public (bus) transportation. Use private conveyance (taxi etc.) for a more secure ride for you, your family, and your baggage
http://www.barcelona-tourist-guide.com/en/transport/barcelona-cruise-port.html