Commonly Used Libraries

Networking

• Retrofit (REST)
  • A simple library for defining restful interfaces
• OkHttp
  • This replaces all platform specified HTTP libraries and is a requirement for HTTP 2
• Gson
• Moshi

Reactive / Functional Programming

• Coroutines
• RxJava
• RxAndroid
• RxBinding
• RxLifecycle

Dependency Injection

• Dagger
  • A dependency injection framework with compile-time code generation

Database

• Realm
  • A Non-SQLite based storage engine designed for mobile
• Room
  • Google's official persistence library with a level of abstraction based on SQLite

Logging

• Timber

Images

While either of the following are allowed, Glide currently has better
feature support including better bitmap pooling, lower default color depth
and GIF support. The APIs are extremely similar and can be mostly considered to
be interchangeable.

• Glide
• Picasso

Filter libraries

• Glide Filters
• Picasso Filters

Unit Testing

• JUnit
• JUnit5
• Mockito
• Mockito-Kotlin

Network Testing

• Mocktrofit

Navigation

• Navigation Component

View Helpers

• ButterKnife
• Calligraphy
• Kotlin Android Extensions

Advanced Time Processing

While historically Joda was the time handling library of choice, JSR-310 succeeds
and often improves upon the API. Written by the same engineer who developed Joda,
it has been integrated into Java 8 and is the new standard. Below is a backport
that has been optimized for loading on Android.

• Android ThreeTen Backport

Additional Resources

• Android Arsenal