Android 4.2 was published in 2013. It was announced ahead of that time, that a built-in Esperanto keyboard will be part of this version, and it will be selectable without having to install any extra application. Users will be able to simply switch on the Esperanto keyboard, by going into the setup for input language.
The Esperanto keyboard was programmed by Jakob Nordfalk. See the news item at: http://www.liberafolio.org/2012/esperanto-igos-integra-parto-de-android-telefonoj