This application illustrates how to implement user preferences with Syncbase. The user logs into a trusted 3rd party -- we use Google auth, but it could be any cloud or nearby service that uses identityd to provide a blessing.
Then when devices are offline and in physical proximity or connected via any network path, the user preferences will sync.
From the command line, you can build and install on the Android emulator or a device with the following command:
./gradlew installDebug