Installing git-annex using Nix-On-Droid is recommended for more advanced users who want to use git-annex at the command line.

To enter a shell with git-annex available to use, run inside Nix-On-Droid: nix-shell -p git git-annex

To avoid needing to do that every time you start Nix-On-Droid, you can add git and git-annex to your environment.packages in ~/.config/nixpkgs/nix-on-droid.nix and then run nix-on-droid switch

The git-annex webapp does not currently work in Nix-On-Droid (as a workaround, run git annex webapp --listen 127.0.0.1 and copy-paste the URL in a browser).