I wanted to explore the Elm architecture and Redux way of building apps on Android. It is heavily inspired by this talk: Managing State with RxJava. The naming conventions are the same and might look weird for people not familiar the aforementioned frameworks, in a nutshell:

• Model: defines common types and data structures
• View: defines how data is displayed - that is in Android lingo an Activity, a Fragment, a View
• Update: defines interactions, it"s responsible for most of the state handling and app logic

Those three files encapsulate classes related to those components of the architecture, the RestApi and WebSocketApi files contain code that handles a trading API.

• UI is minimal since it was not the focus of the assignment
• I found handling websockets with Rx was particularly challenging and I"m not 100% convinced the way I"ve done it it"s the cleanest, clearest and more elegan; it probably need a couple more iterations.

I don"t know if you"re familiar with Reactive Extensions and RxJava but I couldn"t find elegant solutions in a couple of places (marked with TODO#Improve). In case you are familiar with it, I"d appreciate some feedback on that if you"ve got any.

If you"re testing the app using an emulator, fetching a new product id won"t work because of this issue in okhttp

I used Gradle and all standard Android tools so you shouldn"t have any issues with it.