Dictionary for Android

Does anyone have a good way to use an RU>EN dictionary to help with reading Russian texts on an Android phone?

The set-up I have been using is far from perfect. I upload an EPUB to Google Play Books and then read it in the Play Books app. You can then tap to highlight a word, and press the translate button to get Google Translate to pop up. There are a number of problems: It has no proper definitions, I can't get it to work offline, and it's not that quick to get a translation. The worst thing, however, is that you can't force it to translate from Russian. Half the time, it thinks a Russian word is Bulgarian or something else, causing a long delay. There is only a partial workaround as far as I know: if you highlight multiple words at once, it is more likely to recognise the language correctly.

Is there a solution that: 1. Works with ebooks 2. Is a real dictionary. 3. Works offline. 4. Is fast. 5. Recognises lemma forms?

How about a Russian-only dictionary?

If there's nothing that fits my requirements, is it worth getting a Kindle? Does the RU>EN translation function work well?

Thanks.