Replacement for the Java date and time classes prior to Java SE 8
The standard date and time classes prior to Java SE 8 are poor. By tackling this problem head-on, Joda-Time became the de facto standard date and time library for Java prior to Java SE 8. Note that from Java SE 8 onwards, users are asked to migrate to java.time (JSR-310) - a core part of the JDK which replaces this project. The design allows for multiple calendar systems, while still providing a simple API.
...All the library files live in library. The library also uses some Java 8 features, which Android Studio will need to transpile. The library follows the same API as other pickers in the Android framework. The library contains 2 layout versions for each picker. Version 1 is the original layout. It is based on the layout google used in the kitkat and early material design era.