use old offline phone as a hardware wallet? here's what i want to do:

store my private key on an offline phone.
use that offline phone to generate a signed transaction and generate a QR code for me to scan/broadcast with my online phone.

does this exist?!? i cannot find an app to do it

seems like the most secure/convenient way to use bitcoins.
electrum android app can do this! check it out, it's perfect!
also seems like a nice wallet with a lot of features.

your watch-only online electrum can create an unsigned transaction with QR code.
your offline electron can scan then sign it &amp; generate a QR code for you to broadcast with online electrum!