OMDB Android client

This is the repository for the Android client of OMDB. The purpose of this repository is to illustrate the use of Kotlin Coroutines to achieve concurrency in Android programming, which is normally done by RxJava.

Language, libraries and tools

Kotlin the project is 100% written in Kotlin
Coroutines a Kotlin light-weighted concurrency library. This project uses it as a RxJava alternative to demonstrate how it simplifies the code base
Koin a Kotlin light-weighted dependency injection framework. This project use it as a Dagger alternative to demonstrate how simple it is to understand
Retrofit A type-safe HTTP client for Android
Moshi A modern JSON library for Kotlin and Java
Room The Room persistence library provides an abstraction layer over SQLite to allow for more robust database access while harnessing the full power of SQLite
AndroidX libraries
Architecture components provides the life-cycle aware components and observable data
Glide An image loading and caching library for Android focused on smooth scrolling
JUnit4 supports writing Kotlin unit tests
Espresso supports writing Android UI tests
Mockk an alternative of Mockito. Mockk is Kotlin friendly. It has better support for coroutines mocking compared to Mockito

Architecture

The architecture of the project follows the principles of Clean Architecture.

Modularisation

Each of the following layers will be implemented as a its own module in order to keep them separated in alignment with clean architecture and enable parallel builds in gradle.

View

Android UI components belong here. View communicates with ViewModel, subscribing to ViewState using LiveData component. Each View has a ViewModel attached that provides the data required by the view to make state transitions.

ViewModels

This module provides the logic of the View, by providing subscribing components to the view to react to. The ViewModel changes the ViewState based on the use case responses.

Domain

Contain use cases of the application. They provide the application specific business rules and are are responsible of accessing data from different repositories, combine and transform them, to provide single use case business rule.

Data

The Data layer is our access point to external data layers and is used to fetch data from multiple sources (network, cache). It contains implementations of Repositories, which request data from necessary RemoteDataSources and CacheDataSources to feed the use case and make communication between the 2 types of data sources.

Remote

The Remote layer handles all communications with remote sources such as API calls using a Retrofit interface. A RemoteImpl class implements a Remote interface from the Data layer and uses a Service to retrieve data from the API.

Cache

The Cache layer handles all communication with the local databasea.

Tests

Unit tests

Run the following command in a terminal window at the root level of the project

./gradlew test

UI tests

Create and run an AVD Android Emulator (API 16 or above)
Go to developer options and disable all animations
Run the following command in a terminal window at the root level of the project

./gradlew connectedAndroidTest

Or simply right click the app/src/androidTest/java directory and click Run 'All Tests'

tr4n/omdb-client