Overview of Dependency Injection

A class often depends on other classes. The class can create the dependencies or have them supplied as constructor parameters. Dependency injection (DI) is the process of providing dependencies from outside a class. DI is a good development practice. It improves code reusability, makes refactoring more effortless, and makes the code testable. For example, if our ViewModel depends on a Retrofit instance, we can pass a mock instance of Retrofit for our unit tests. Without DI, testing the ViewModel would be challenging as the class would initialize the Retrofit instance.

Overview

A class could ...