Version 1.1 of the Register API is now available on Android as of Square Register version 4.48.
Version 1.1 includes:
Support for split tender transactions: transactions completed using multiple tender instruments.
Support for Square Prepaid Gift Card transactions, as part of the CARD tender type.
CARD_ON_FILEtender type to allow charging a previously-stored card instrument.
Support for linking customers to transactions.
For more information:
See the GitHub CHANGELOG for Version 1.1.
See Register API Overview for an overview of how the Register API works.
See Using the Register API for Android to learn how to add Register API functionality to your Android app.
See this Github repo for a sample Android application that uses the Register API.