I've released an external code and sprite editor for AppGameKit Mobile. It works on Android smartphones.
I aim to create an easy-to-use editor for smartphones.
In this editor, you write in a unique Perl-like language called Gobln instead of BASIC. It's basically replaced by BASIC, so it's easy to understand. With the simple framework included, you can program more easily.
You can output the sprite as a png file or insert it as a hexadecimal string in your source code.
(for Android 6 or later)