OpenCab is a set of interface definitions that permit multiple mobile apps running on a single device to communicate with each other at runtime to present a seamless experience for the driver. It's designed to serve truck drivers and other field users who drive vehicles as a key part of their jobs.
Although this documentation is in the form of a Java API, OpenCab isn't an SDK. Instead, it's a set of agreed-upon Android Intents and ContentProviders that, if implemented according to the definitions documented here, permit cross-app communication of structured data without a proprietary SDK.
org.opencabstandard.provider for the technical details about the types of data that can be shared between apps.
Java interface files that define the contracts for OpenCab providers.