Sample illustrating the use of modern Android architectures and components.

In order to understand the example fully, we recommend reading the following documentation first:

• ViewModel and LiveData documentation
• Flux architecture documentation
• Mini repo documentation

The app in this example is a barebones Pokédex app that uses the API provided by https://pokeapi.co/ to display a subset of Pokémon and their initial moves.

The app flow is driven via Flux actions to load Pokémon data and displayed to the user via ViewModels and LiveData.

The app is divided in several packages:

• domain: contains the classes related to business logic: stores, controllers, application models...
• network: contains the classes related to network communication: API contracts, network models...
• ui: contains the classes related to UI: ViewModels, LiveDatas, fragments, activities, views...

In each of these packages you can find sub-packages by functionality. These functionalities are:

• pokemon: classes related to Pokémon data retrieving, such as Pokédex number, images and so on
• moves: classes related to Pokémon moves and their stats and properties

The basic flow of the app is as follows:

• When the PokemonListActivity is loaded we setup the related ViewModel, that way the ViewModel will dispatch an action to load Pokémon data.
• As soon as the Pokémon data is loaded the ViewModel will trigger an action to load a subset of each Pokémon moves, one action per Pokémon.
• The ViewModel listens to changes in both PokemonStore and MovesStore so it can compose the final data passed to the view (referred as ViewData, which has a method to transform store states into view-consumable info) and emits it via a LiveData stored in the ViewModel so the activity can render both Pokémon and related moves.

We decided to split the tests in two types:

We can test if the UI works as expected by writing an UI test using Espresso via the Kakao library. The architecture allows us to create a mock of the ViewModel using Mockito and then replace the LiveData that it contains for our own test LiveData.

This makes creating UI tests a breeze: just emit the values you need using the test LiveData and do your screen assertions.

We can unit test the mapping functions of each ViewData so we can ensure that the proper information is properly generated for view consumption.

• Kodein ViewModel injection: https://proandroiddev.com/android-viewmodel-dependency-injection-with-kodein-249f80f083c9
• Kodein testing sample: https://github.com/Karumi/kodein-sample-testing
• Basic Flux implementation: https://https://github.com/pabloogc/FakeShop/
• Mock Kotlin classes in tests: https://proandroiddev.com/mocking-androidtest-in-kotlin-51f0a603d500

   Copyright 2019 BQ

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