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 Flows. ViewModels 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 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 for most assertions
• cashapp/turbine for complex coroutine tests
• 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.