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.
Code editor

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.
- Features
Built-in keyboard
Keyword suggestion
Templates system
Sprite editor

You can output the sprite as a png file or insert it as a hexadecimal string in your source code.
Tutorial
https://www.youtube.com/watch?v=4OeMTAaWH9k
Download
http://ni.10-59.com/zip/gobs.apk
(for Android 6 or later)