# Now in Android Project

Now in Android is a native Android mobile application written in Kotlin. It provides regular news
about Android development. Users can choose to follow topics, be notified when new content is
available, and bookmark items.

## Architecture

This project is a modern Android application that follows the official architecture guidance from Google. It is a reactive, single-activity app that uses the following:

-   **UI:** Built entirely with Jetpack Compose, including Material 3 components and adaptive layouts for different screen sizes.
-   **State Management:** Unidirectional Data Flow (UDF) is implemented using Kotlin Coroutines and `Flow`s. `ViewModel`s act as state holders, exposing UI state as streams of data.
-   **Dependency Injection:** Hilt is used for dependency injection throughout the app, simplifying the management of dependencies and improving testability.
-   **Navigation:** Navigation is handled by Jetpack Navigation 2 for Compose, allowing for a declarative and type-safe way to navigate between screens.
-   **Data:** The data layer is implemented using the repository pattern.
    -   **Local Data:** Room and DataStore are used for local data persistence.
    -   **Remote Data:** Retrofit and OkHttp are used for fetching data from the network.
-   **Background Processing:** WorkManager is used for deferrable background tasks.

## Modules

The main Android app lives in the `app/` folder. Feature modules live in `feature/` and core and shared modules in `core/`.

## Commands to Build & Test

The app and Android libraries have two product flavors: `demo` and `prod`, and two build types: `debug` and `release`.

- Build: `./gradlew assemble{Variant}`. Typically `assembleDemoDebug`.
- Fix linting/formatting: `./gradlew --init-script gradle/init.gradle.kts spotlessApply`
- Run local tests: `./gradlew {variant}Test`
- Run single test: `./gradlew {variant}Test --tests "com.example.myapp.MyTestClass"`
- Run local screenshot tests: `./gradlew verifyRoborazziDemoDebug`

### Instrumented tests

- Gradle-managed devices to run on device tests: `./gradlew pixel6api31aospDebugAndroidTest`. Also `pixel4api30aospatdDebugAndroidTest` and `pixelcapi30aospatdDebugAndroidTest`.

### Creating tests

#### Instrumented tests

- Tests for UI features should only use `ComposeTestRule` with a `ComponentActivity`.
- Bigger tests live in the `:app` module and they can start activities like `MainActivity`.

#### Local tests

- [kotlinx.coroutines](https://github.com/Kotlin/kotlinx.coroutines) for most assertions
- [cashapp/turbine](https://github.com/cashapp/turbine) for complex coroutine tests
- [google/truth](https://github.com/google/truth) for assertions

## Continuous integration

- The workflows are defined in `.github/workflows/*.yaml` and they contain various checks.
- Screenshot tests are generated by CI, so they shouldn't be checked into the repo from a workstation.

## Version control and code location

- The project uses git and is hosted in https://github.com/android/nowinandroid.