This app was mentioned in 1 comment, with an average of 3.00 upvotes
here are my favourites:
https://play.google.com/store/apps/details?id=com.utechstudio.cflashcard
https://play.google.com/store/apps/details?id=com.gamestolearnenglish.chineseinflow
https://play.google.com/store/apps/details?id=org.nick.hanzirecognizer
https://play.google.com/store/apps/details?id=info.xiaoma.hanzi