RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM.

Getting Started with Spring Boot 3:

Render After Effects animations natively on Android and iOS, Web, and React Native

An image loading and caching library for Android focused on smooth scrolling

ZXing ("Zebra Crossing") barcode scanning library for Java, Android

Bind Android views and callbacks to fields and methods.

Desktop/Android/HTML5/iOS Java game development framework

This project is deprecated and stale. The latest ExoPlayer code is available in https://github.com/androidx/media

RxJava bindings for Android

A fast dependency injector for Android and Java.

Modular and customizable Material Design UI components for Android

Most popular Mocking framework for unit tests written in Java

An Android transformation library providing a variety of image transformations for Glide.

A collection of samples demonstrating different frameworks and techniques for automated testing

Epoxy is an Android library for building complex screens in a RecyclerView

Generate Java types from JSON or JSON Schema and annotate those types for data-binding with Jackson, Gson, etc

Android Unit Testing Framework

Apache Groovy: A powerful multi-faceted programming language for the JVM platform

A diagram of the Android Activity / Fragment lifecycle

Keep your code spotless

Multiple samples showing the best practices in views-widgets on Android.

🔬 Java Code Coverage Library

Open Location Code is a library to generate short codes, called "plus codes", that can be used as digital addresses where street addresses don't exist.

Android's TextView that can expand/collapse like the Google Play's app description

A collection of sample apps to demonstrate how to use Google's ML Kit APIs on Android and iOS

Bundletool is a command-line tool to manipulate Android App Bundles

Groupie helps you display and manage complex RecyclerView layouts.

An adaptation of the JSR-310 backport for Android.

A SeekBar suited for showing a preview of something. As seen in Google Play Movies.

Code for Head First Design Patterns book (2020)