ET3D: Many Android versions of games are full of permissions to get access to your info, and that IMO doesn't sit well with the DRM-free culture, even if the games themselves can install and run without an internet connection.
This is why i don't like android. Asking for permissions like wifi isn't a big deal (in fact it may need access if it has multiplayer elements or is a multiplayer game) but asking for permission to access my accounts or photos or anything personal is way too much for me. I don't have a tablet and i don't plan to buy one, but i have a smartphone already and for sometime now i think if it would be better to install CyanogenMod, at least in terms of security.
Anyway, back to BG; i think it is a good thing to play BG 1 before BG 2 because you'll get more attached (or more connected - don't know what word to use but you get the meaning!) to the characters. When you start BG 2, there are some characters in the first screen;
- Who are they? They know you but do you know them?
- What is this little rodent?
- Later you find people that remember you; wouldn't it have been better if you actually remember them too?
Surely you can search for anything in the wiki so you don't get lost, but i think that way you break the immersion.
TD;DR You can play BG 2 without playing BG 1. But i'm 100% sure that if you play BG 1, you'll enjoy the story of BG 2 and the characters better! ;-)