Alright, yet another Android clunky POC ready to be broken by you. I call it Nestr (you can propose new names!) and it's basically a web browser connected to Amber.
That means you can visit nostr web-apps on your android, use them like native Apps (or that's the WIP plan) and login with Amber as the Alby/nos2x.

I just added 5 sites to play with, but you can say the list of pottential apps is basically infinite. Have fun.