Global error handling for REST requests.

Handle session expirations and 401 error codes. The following code will be activated if the API responds with a 401 (no authentication). If there’s a token that should be renewed, we first renew the token and if this is successful we try the original request again.

A very complete recipe that implements a RecyclerView that pulls in paginated data, using Retrofit, LiveData. It includes example models, adapter, viewholders, and a viewholder for displaying the network state in case of an error.

With this snippet you can easily and quickly mock an API during developmentby placing JSON files in your res/raw/ folder. This comes in handy when the actual API does not exist yet.