This is a simple demo code accessing the Google Maps Directions API using retrofit. User input is done through a MapFragment. Source code available As of today 16/09/15, this is clearly not an intended use for the API. From. "This service is generally designed for calculating directions for static addresses for placement of application content on a map;
Download the free installation package of DirectionsOnMapv2WithRetrofit 1.0 and take a look at users' reviews on Droid Informer. The app runs on Android devices 4.3 and higher. This application is totally secure to download. @F8Full is the creator of the tool which refers to the Libraries & Demo category.
Over 10 users downloaded and set up DirectionsOnMapv2WithRetrofit and the latest update was on Sep 16, 2015. On Google Play, the app was rated 4.1 by its users.