Rikaichan(ish). Only for android apps. Like, if I hover over a word in the Pixiv app, it will translate it for me.

I know this exists for text already (like in pdf readers, I think, and for mobile browsers), but is there anything like it that will work for apps in general?

I don't believe so.
But if you only need it for occasional use, you could take a screenshot (i think power+volume down on android 4+) and then try using cb's ocr manga reader: http://ocrmangareaderforandroid.sourceforge.net/

This one looked useful and has good reviews, but it wouldn't install on my phone so I can't recommend it personally. (Copy text rather than hover.)
https://play.google.com/store/apps/detai...dictionary

Ah, you said you already have one for text. I should read the question more carefully =/

May be this can help you
https://play.google.com/store/apps/detai...zyz.mobile

It shows dictionary entry when you tap on word

alleo Wrote:May be this can help you
https://play.google.com/store/apps/detai...zyz.mobile
It shows dictionary entry when you tap on word

Thanks for posting this. A little awkward to use but very useful

OP please rename the title of this thread something more appropriate

You can have any app runing on your phone while this window keeps on top always. Whenever you select and copy any text from any application by the android "copy/ paste" system by default, this window captures the sentence and you can touch on its words in order to know information.

https://lh5.ggpht.com/nAcVLGgh7dlAKH1aI5...t5vNM=h900

The app consists in:
- Dictionaries
- Conjugations
- Emerging window with "rikaichan/kun seemed stuff"
- It also has an interesting function that analyses any Japanese text, and shows words colourized by type. Ah, and you can add furigana too. All functions absolutely off-line, not internet connection required.

* More features and actualizations coming soon...

https://play.google.com/store/apps/detai...okugakusha