Bit Learning

An Android e-learning platform built with Kotlin and Jetpack Compose, featuring course management, video playback, community forums, and an integrated Python code compiler.

Tech Stack

Layer	Technology
Language	Kotlin 2.0.21
UI Framework	Jetpack Compose + Material 3
Architecture	Clean Architecture (core → data → domain → features)
DI	Hilt (Dagger)
Networking	Retrofit 2 + OkHttp 4
Serialization	Gson + Jackson
Local Storage	Jetpack DataStore
Navigation	Jetpack Navigation Compose
Video Player	Media3 / ExoPlayer
Image Loading	Coil 3
QR Scanning	ML Kit Barcode
Payments	Stripe Android SDK
Auth	Google Sign-In, GitHub OAuth2, JWT
Python Runtime	KtxPy (embedded CPython)
Code Editor	Sora Editor + TextMate
Terminal	Termux terminal-emulator
Logging	Timber
Linting	Spotless + ktlint
CI/CD	Codemagic

Project Structure

bitlearning/
├── app/                          # Main application module
│   └── src/main/java/com/app/bitlearning/
│       ├── BitLearningApp.kt     # Application class (Hilt entry, Python init)
│       ├── MainActivity.kt       # Single Activity, deep link handling
│       ├── Navigation.kt         # NavHost + route definitions
│       ├── core/
│       │   ├── common/           # Shared Compose components, theme, typography
│       │   ├── database/         # Room database (prepared for local caching)
│       │   ├── log/              # Logging utilities
│       │   ├── network/          # Retrofit ApiService, OkHttp config, AuthInterceptor
│       │   └── preferences/      # DataStore-backed app preferences
│       ├── data/
│       │   ├── mapper/           # DTO ↔ Domain model mappers
│       │   └── repository/       # Repository implementations
│       ├── domain/
│       │   ├── model/            # Domain entities (User, Course, Lecture, etc.)
│       │   └── repository/       # Repository interfaces (contracts)
│       └── features/
│           ├── auth/             # Login, Register, Google/GitHub OAuth2
│           ├── onboarding/       # First-launch onboarding flow
│           ├── splash/           # Splash screen with auth state check
│           ├── home/             # Home dashboard
│           ├── courses/          # Course catalog browsing
│           ├── coursedetail/      # Course detail + section/lecture list
│           ├── player/           # Video player (ExoPlayer)
│           ├── search/           # Course search
│           ├── profile/          # User profile, edit, certificates
│           ├── history/          # Learning history
│           ├── forum/            # Community forum (posts, comments, likes)
│           ├── notification/     # Notifications
│           ├── notificationsetting/ # Notification preferences
│           ├── payment/          # Payment settings (Stripe)
│           └── support/          # Help & support
├── ktxpy-module/                 # Embedded Python compiler module
│   ├── app/                      # KtxPy library (Sora editor, terminal, Python runtime)
│   │   ├── arch_arm32/           # Python 7z assets for ARM 32-bit
│   │   ├── arch_arm64-v8a/       # Python 7z assets for ARM 64-bit
│   │   ├── arch_x86/             # Python 7z assets for x86
│   │   └── arch_x86_64/          # Python 7z assets for x86_64
│   └── libp7zip/                 # Native 7zip decompression library
├── gradle/
│   └── libs.versions.toml        # Version catalog
├── codemagic.yaml                # CI/CD pipeline config
└── build.gradle.kts              # Root build script (Spotless, Hilt, KSP)

System Architecture

Clean Architecture Layers

┌─────────────────────────────────────────────────┐
│                  features/                       │
│  (UI screens + ViewModels per feature module)    │
├─────────────────────────────────────────────────┤
│                  domain/                         │
│  (Repository interfaces, domain models, enums)   │
├─────────────────────────────────────────────────┤
│                  data/                           │
│  (Repository impls, DTO mappers, API delegation) │
├─────────────────────────────────────────────────┤
│                  core/                           │
│  (Network, DataStore, Theme, Shared Components)  │
└─────────────────────────────────────────────────┘

• features/ — Each feature is a self-contained module with its own ui/ (Composables + ViewModel). Dependencies flow inward only.
• domain/ — Pure Kotlin. Defines repository contracts and domain entities (User, Course, Lecture, ForumPost, etc.). No Android framework dependencies.
• data/ — Implements domain repository interfaces. Contains AuthRepositoryDelegator for switching between mock and real backends, plus DTO-to-domain mappers.
• core/ — Cross-cutting concerns: Retrofit/OkHttp networking with JWT AuthInterceptor, AppPreferences (DataStore), Material 3 theme, and reusable Compose components.

Navigation

Single-Activity architecture using Jetpack Navigation Compose. All routes are defined in Navigation.kt via the Routes object. Supports Android App Links deep linking (https://bit-learning.lch.id.vn/open-mobile?screen=...&id=...).

Navigation flow:

Splash → Onboarding → Auth → Home ─┬─ Courses → CourseDetail → Player
                                    ├─ Search
                                    ├─ Profile → EditProfile / Certificates / History
                                    ├─ Forum
                                    ├─ Notifications
                                    └─ Python Compiler (KtxPy)

Networking

• Retrofit 2 with GsonConverterFactory for REST API communication
• OkHttp 4 with HttpLoggingInterceptor and custom AuthInterceptor (attaches Bearer JWT token)
• Cookie Jar (JavaNetCookieJar) for automatic HttpOnly refresh-token handling
• All API responses wrapped in ApiWrapper<T> envelope: { status, message, data?, page?, error? }
• Backend base URL: https://bit-api-dev.lch.id.vn/api/

Authentication

Method	Flow
Email/Password	POST /auth/login → JWT access token stored in DataStore
Google Sign-In	Android SDK ID Token → POST /auth/oauth2/google/mobile
GitHub OAuth2	Authorization code → POST /auth/oauth2/github

Python Compiler Integration

The app embeds KtxPy, a Python runtime for Android:

• Initialized in BitLearningApp.onCreate() (crash handler, file manager, Timber logging)
• Launched as a separate Activity (github.psicodes.ktxpy.activities.HomeActivity)
• Includes Sora code editor with TextMate syntax highlighting
• Termux terminal emulator for interactive Python sessions
• Architecture-specific Python 7z assets decompressed via libp7zip at first run

Dependency Injection

Hilt (Dagger) with KSP annotation processing. @HiltAndroidApp on BitLearningApp, @AndroidEntryPoint on MainActivity. Network module provides singleton OkHttpClient, Retrofit, and BitLearningApiService instances.

Build Variants

The project uses product flavors for CPU architecture targeting:

Flavor	Architecture	Use Case
arch_arm64	arm64-v8a	Physical devices (most modern phones)
arch_x86_64	x86_64	Android Emulator

Recommended Build Variants

Emulator:

:app                → arch_x86_64Debug
:ktxpy-module:app   → arch_x86_64Debug
:ktxpy-module:libp7zip → debug

Physical device (ARM64):

:app                → arch_arm64Debug
:ktxpy-module:app   → arch_arm64Debug
:ktxpy-module:libp7zip → debug

Getting Started

Prerequisites

• Android Studio Ladybug or later
• JDK 11+
• Android SDK 36 (compile & target)
• Min SDK 24

Setup

1. Clone the repository:

   git clone <repository-url>

2. Create keystore.properties in the project root (for release builds):

   storeFile=path/to/your.keystore
   storePassword=your_store_password
   keyAlias=your_key_alias
   keyPassword=your_key_password

3. Open in Android Studio and sync Gradle.

4. Select the appropriate build variant for your target device (see Build Variants above).

5. Run the app.

CI/CD

Automated builds via Codemagic:

• Runs on mac_mini_m2 instances
• Builds release AAB with auto-incremented version code from Google Play
• Publishes to Google Play internal track as draft
• Gradle caching enabled for faster builds

API Endpoints

The app communicates with a Spring Boot backend. Key endpoint groups:

Group	Endpoints
Auth	/auth/login, /auth/register, /auth/logout, /auth/oauth2/*
Courses	/courses, /courses/{id}, /courses/grade/{grade}, /courses/my-courses
Enrollment	/enrollments/enroll/{courseId}, /enrollments/my-courses, /enrollments/courses/{courseId}/access
Learning	/learning/progress/lectures/{lectureId}/complete
Users	/users/profile, /users/{id}/avatar, /users/{id}/cover
Onboarding	/onboarding/pages
Forum	/posts, /posts/{id}, /comments, /posts/{postId}/like, /posts/{postId}/media

Localization

The app supports:

• English (default)
• Vietnamese (values-vi/)

License

Copyright © 2026 Bit Learning. All rights reserved. Proprietary and confidential — see license headers in source files.