This app was mentioned in 1 comment, with an average of 1.00 upvote
After considerable research, I installed "Coin Price Ticker" for this specific purpose. Couldn't be happier. One thing is that you have to enter the amount of ETH you have (and not, say, give it your wallet IDs), which is totally fine with me.
https://play.google.com/store/apps/details?id=wiskunde.nl.coinpriceticker