When your users want to get from one location to another, don’t push them out of your application into a generic map application. Instead, keep them engaged with your application 100% of the time with in-app turn-by-turn navigation.
The Navigation SDK for Android contains logic needed to get timed navigation instructions.
It plays well with the open source GraphHopper server as well as the GraphHopper Directions API.
It is 100% open source and was forked 2018 from Mapbox due to licensing issues.
If you are looking to include this inside your project, please also have a look into the Android example.
Add this snippet to your build.gradle file to use this SDK (libandroid-navigation):
implementation 'com.graphhopper.navigation:navigation-android:0.1.0'