Can you download database and opening in it so you u can work offline?
Chessbase for Android

It's an application that allows you to search games from strong players. This includes searching for games with the opening moves that you enter. I don't think it allows you to download the whole database, though.

Ok I tried it this morning and already wrote suggestions to the developer. I undestand its simplistic purpose so I didnt ask too much.
Cons:
1. Board doesn't utilize the full width of the screen. Our phone screens are already small yet they made the chessboard even smaller with thick side bezels.
solution: Hide the status bar to utilize more space.
2. The move navigation buttons (previous, forward) are hit and miss that i often tap the wrong button.
solution: Swipe the moves Notation panel left or right to navigate the game back or forward. Its intuitive because youre swiping the move list and swiping doesn't need acurracy.
3. Only PGN files are supported. Would be better if I can also open their own Chessbase(cbh) files. As well as their own Opening Book (ctg)
hope they'll listen.
I wish there's a Windows Mobile emulator for Android because Pocket Fritz is still more functional for the serious chessplayer. But I do believe that chessbase for Android will catch up in the long run.
Last night, I found the Chessbase app for my t-mobile android phone. It's $4.99 USD, but you have access to their database. That's a good deal. It's an excellent deal, actually.
So, I looked up a game by N. Krogius, the author of Psychology in Chess. In this game Krogius actually lost, but it was instructional for me no less. I think that's interesting ... going over a game in just minutes that took two players multiple hours to create.
Anyways...I'm not a paid spokesman here. Just sharing a resource with members of this forum who might happen to have Android phones.