Why is DI needed?

DI is not a must for all projects. Until now, our Restaurants app worked just fine without any DI incorporated. Yet, while not including DI might not seem like a big issue, by incorporating it you bring a lot of benefits to your project; the most notable advantages are that you can do the following:

• Write less boilerplate code.
• Write testable classes.

Let's cover these two next.

Write less boilerplate code

Let's circle back to our Restaurants app, and let's have a look at how we instantiate the Retrofit interface within the RestaurantsRepository class:

class RestaurantsRepository {
    private var restInterface: RestaurantsApiService =
        Retrofit.Builder()
             .addConverterFactory(
                 GsonConverterFactory...