One of the things that made AndEngine really useful was paths and different modifiers. With those it was possible to animate and fade just about anything. Tween Engine takes this to a whole new level and handles interpolation tasks for any attribute regarding any given object. Sort of. But it works!
However, as we are getting familiar with Gradle and Android Studio the library needs to be added. Step one is making “libs” directories in both core and android and put the tween-engine-api.jar and tween-engine-api-source.jar into those folders. Step two is adding them to the corresponding dependencies sections in the build.gradle file:
compile fileTree (dir: "libs", includes: ['*.jar'])
Finally it is a good idea to rebuild the project, and that is it! A perfect and essential complementary library for every libGDX project.