Compose Showcase — Jetpack Compose + MVVM

A showcase Android app built with Jetpack Compose and MVVM. Uses a single-activity Compose UI, Room, Hilt, and a clear layered architecture.

What This Showcase Demonstrates

Architecture (MVVM + Clean separation)

• Model: Domain models (Task, TaskPriority) and data entities (TaskEntity) kept separate.
• View: Pure Compose UI; no logic in composables beyond calling ViewModel.
• ViewModel: UI state via StateFlow, one-way data flow, use cases for business operations.

Tech Stack

Layer	Technology
UI	Jetpack Compose, Material 3, Navigation Compose
State	StateFlow + collectAsState()
DI	Hilt (ViewModel and Repository scoping)
Local DB	Room (DAO, DB, migrations-ready)
Async	Kotlin Coroutines + Flow
Architecture	Repository pattern, Use cases (domain layer)

Details

1. Single source of truth: Repository abstracts data; ViewModels never touch Room/DAO directly.
2. Reactive streams: Flow from DAO → Repository → Use case → ViewModel → UI.
3. Use cases: One responsibility per use case (GetAllTasks, SearchTasks, AddTask, etc.).
4. Scoped ViewModels: hiltViewModel() per Nav graph destination so each screen has correct scope (e.g. detail screen for a specific taskId).
5. UI state modeling: Dedicated *UiState data classes (loading, error, content).
6. Navigation: Type-safe route constants and NavHost with arguments (taskId).
7. Dependency injection: Interface for repository in domain, implementation in data; Hilt modules for DB and DAO.

Project Structure

app/src/main/java/com/showcase/app/
├── data/
│   ├── local/           # Room: entities, DAO, Database
│   └── repository/      # Repository implementations
├── di/                  # Hilt modules
├── domain/
│   ├── model/           # Domain models
│   ├── repository/      # Repository interfaces
│   └── usecase/         # Use cases
├── ui/
│   ├── addtask/         # Add task screen + ViewModel
│   ├── navigation/      # Nav routes + NavHost
│   ├── taskdetail/      # Task detail screen + ViewModel
│   ├── tasklist/        # Task list screen + ViewModel
│   └── theme/           # Material 3 theme + typography
├── MainActivity.kt
└── ShowcaseApplication.kt

How to Run

Option A: Android Studio (easiest)

1. Open the project in Android Studio (Hedgehog or newer recommended).
2. Let Android Studio create local.properties with your SDK path (or set Settings → Android SDK and note the path).
3. Sync Gradle and run on an emulator or device (API 26+).

Option B: Command line

Gradle needs the Android SDK path. Use either ANDROID_HOME or a local.properties file.

Using ANDROID_HOME (no local.properties needed):

# Default SDK path when installed via Android Studio on macOS:
export ANDROID_HOME=$HOME/Library/Android/sdk
# If your SDK is elsewhere, use that path instead (e.g. from Android Studio → Settings → Android SDK).

./gradlew installDebug

Using local.properties (so you don’t set ANDROID_HOME every time):

# Create the file (use your actual SDK path; common on macOS: $HOME/Library/Android/sdk)
echo "sdk.dir=$HOME/Library/Android/sdk" > local.properties
./gradlew installDebug

If you see "SDK location not found", the path in local.properties or ANDROID_HOME is wrong or the SDK isn’t installed. Install the SDK via Android Studio (Tools → SDK Manager) and use the path shown there.

Features Implemented

• Task list: Loads from Room, shows priority and completion.
• Search: Reactive search over title/description via Flow.
• Add task: Form with title, description, priority; validation and error state.
• Task detail: View task, toggle complete, delete (with back navigation).
• Persistence: All data stored in Room; survives process death.

Possible Extensions (for further showcase)

• Add RemoteMediator or offline-first with a remote API.
• Add unit tests for ViewModels and use cases.
• Add UI tests with Compose Testing.
• Add saved state for search query (e.g. SavedStateHandle).
• Add exportSchema = true and migration tests for Room.

Screenshots