"Processing for Android: Create Mobile, Sensor-Aware, and VR Applications Using Processing" is a book I have published in 2017 with Apress. This book offers a detailed coverage of Processing for Android, from the first steps with installation and the basics of code sketching, to advanced applications of the Processing and Android APIs to create original apps using sensor data, geolocation, and Virtual Reality.
Many thanks to Ben Fry, who wrote the preface, and Casey Reas, for giving permission to use images from his piece "A Mathematic Theory of Communication" in the cover.
The first three chapters of the book are available in this site for free, together with all the code examples. Click on the "Get the Full Book" link in the menu, or on the image below, to order the eBook and softcover versions.