An unofficial Android companion app for managing XTEINK X4 e-paper displays via WiFi hotspot connectivity.

⚠️ Disclaimer: This is an unofficial, community-developed application. Hojo is not affiliated with, endorsed by, or sponsored by XTEINK in any way. Use at your own risk.

Hojo is a native Android application built with Jetpack Compose that provides a seamless interface for connecting to and managing XTEINK X4 e-paper displays. The app handles WiFi network switching, file management, and wallpaper customization.

Note: This app is specifically designed for the XTEINK X4 e-paper display and has only been tested on this device. Compatibility with other e-paper displays is not guaranteed.

• Automatic WiFi hotspot detection and connection to e-paper devices
• Intelligent network binding with fallback to internet connectivity
• Real-time connection status monitoring
• Network health checks with automatic retry logic

• Browse and navigate the e-paper device's file system
• Upload files from your Android device
• Create folders and organize content
• Rename and delete files/folders
• Download files from the e-paper device

• Create custom wallpapers optimized for e-paper displays (480x800px, 3:5 aspect ratio)
• Image cropping and editing tools
• Direct upload to e-paper device

• Convert documents to EPUB format optimized for e-paper displays
• Customizable font and layout settings
• Native conversion engine

• Convert web articles to EPUB format
• Uploads to /books directory on device for quick content display

• Theme customization (System Default, Light, Dark)
• View app version information
• Link to GitHub repository

• Language: Kotlin
• UI Framework: Jetpack Compose with Material 3
• Architecture: MVVM with ViewModels and StateFlow
• Minimum SDK: 26 (Android 8.0)
• Target SDK: 34 (Android 14)

• AndroidX Core KTX
• Jetpack Compose BOM
• Material 3 with Extended Icons
• Navigation Compose
• Hilt for dependency injection
• OkHttp for networking
• Gson for JSON parsing
• Jsoup for HTML parsing
• epublib for EPUB generation
• Android Image Cropper for image editing

app/src/main/java/wtf/anurag/hojo/
├── connectivity/          # E-paper device connectivity management
│   ├── EpaperConnectivityManager.kt
│   └── SmartNetworkInterceptor.kt
├── data/                  # Data models and repositories
│   ├── model/            # Data classes (FileItem, StorageStatus, etc.)
│   ├── repository/       # Repositories (ThemeRepository, etc.)
│   ├── ConnectivityRepository.kt
│   ├── DefaultConnectivityRepository.kt
│   ├── FileManagerRepository.kt
│   └── ProgressRequestBody.kt
├── di/                    # Dependency injection (Hilt)
│   └── AppModule.kt
├── ui/                    # UI components and screens
│   ├── apps/             # Feature apps
│   │   ├── converter/    # EPUB converter
│   │   ├── filemanager/  # File browser
│   │   ├── quicklink/    # Quick link modal
│   │   ├── settings/     # App settings
│   │   └── wallpaper/    # Wallpaper editor
│   ├── components/       # Reusable UI components
│   ├── viewmodels/       # ViewModels for state management
│   │   ├── ConnectivityViewModel.kt
│   │   ├── FileManagerViewModel.kt
│   │   ├── QuickLinkViewModel.kt
│   │   ├── SettingsViewModel.kt
│   │   └── WallpaperViewModel.kt
│   ├── theme/            # App theming
│   └── MainScreen.kt     # Main navigation screen
├── utils/                # Utility functions
├── HojoApplication.kt    # Application class
└── MainActivity.kt       # App entry point

• Android Studio Hedgehog or newer
• JDK 8 or higher
• Android SDK 34

1. Clone the repository:

git clone <repository-url>
cd hojo

2. Open the project in Android Studio

3. Sync Gradle dependencies

4. Build the project:

./gradlew build

5. Run on device/emulator:

./gradlew installDebug

./gradlew assembleRelease

The release APK will be generated at app/build/outputs/apk/release/

Note: These connection settings were reverse-engineered from the device and may change with firmware updates.

The app is configured to connect to the XTEINK X4 e-paper display with the following default settings:

• SSID: E-Paper
• Password: 12345678
• IP Address: 192.168.3.3
• Port: 80

These settings can be modified in EpaperConnectivityManager.kt if your device uses different credentials.

The app requires the following permissions:

• INTERNET - For network communication
• ACCESS_WIFI_STATE - To check WiFi status
• CHANGE_WIFI_STATE - To connect to e-paper hotspot
• CHANGE_WIFI_MULTICAST_STATE - Required for some network discovery operations
• ACCESS_NETWORK_STATE - To monitor network connectivity
• CHANGE_NETWORK_STATE - To bind to specific networks
• NEARBY_WIFI_DEVICES - For WiFi device discovery (Android 13+)
• ACCESS_FINE_LOCATION - Required for WiFi scanning

1. Connect to E-Paper Device

   • Launch the app
   • Tap the "Connect" button on the home screen
   • Grant required permissions when prompted
   • The app will automatically connect to the e-paper hotspot

2. Manage Files

   • Tap "File Manager" from the home screen
   • Navigate through folders
   • Use the toolbar to create folders or upload files
   • Long-press files for rename/delete options

3. Create Wallpapers

   • Tap "Wallpaper Editor" from the home screen
   • Select an image from your device
   • Crop and adjust as needed
   • Save to upload directly to the e-paper device

4. Convert to EPUB

   • Tap "EPUB Converter" from the home screen
   • Select a document from your device
   • Customize font and layout settings
   • Convert and upload to your e-paper device

5. Quick Link

   • Tap "Quick Link" from the home screen
   • Enter a URL
   • The app converts and uploads the content to your e-paper display

• Follow Kotlin coding conventions
• Use meaningful variable and function names
• Document complex logic with comments

• UI components use Jetpack Compose
• State management via ViewModels and StateFlow
• Dependency injection using Hilt
• Network operations on IO dispatcher
• UI updates on Main dispatcher

Contributions are welcome! This is a community project, and we appreciate any help improving it.

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

• XTEINK is a trademark of its respective owner.
• This project is an independent, community-driven effort and is not officially supported by XTEINK.
• The developers of this app are not responsible for any damage to your e-paper device.
• Use this software at your own risk.

Made with ❤️ by the community, for the community.