android_client/
├── app/
│   ├── src/
│   │   └── main/
│   │       ├── java/com/scar/chat/
│   │       │   ├── MainActivity.java           # Main activity with tabs
│   │       │   ├── ChatConnection.java         # SSL/TLS connection handler
│   │       │   ├── ChatFragment.java           # Chat UI fragment
│   │       │   ├── VideoFragment.java          # Video/camera UI fragment
│   │       │   └── TabLayoutMediator.java      # Tab mediator
│   │       ├── res/
│   │       │   ├── layout/
│   │       │   │   ├── activity_main.xml       # Main activity layout
│   │       │   │   ├── fragment_chat.xml       # Chat tab layout
│   │       │   │   └── fragment_video.xml      # Video tab layout
│   │       │   └── values/
│   │       │       ├── strings.xml             # String resources
│   │       │       └── colors.xml              # Color resources
│   │       └── AndroidManifest.xml             # App manifest
│   └── build.gradle                            # App-level build config
├── build.gradle                                # Project-level build config
├── settings.gradle                             # Gradle settings
├── gradle/wrapper/                             # Gradle wrapper
└── build.sh                                    # Build script

Features

TLS/SSL Encryption: Secure connection to chat server
Multi-tab Interface: Chat tab for messaging, Video tab for camera
Camera Support: Enable/disable camera with device selection
Real-time Chat: Send and receive messages in real-time
Customization: Background color, text color, and transparency controls (UI ready)
Multi-client Support: Connect multiple Android devices to same server

Building

Prerequisites

Install Android Studio or Android SDK + Gradle
Java JDK 11+ installed and in PATH
ANDROID_HOME environment variable set to SDK location

On Linux/macOS:

export ANDROID_HOME=$HOME/Android/Sdk
export PATH=$PATH:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools

On Windows (PowerShell):

$env:ANDROID_HOME = "$env:USERPROFILE\AppData\Local\Android\Sdk"
$env:PATH += ";$env:ANDROID_HOME\tools;$env:ANDROID_HOME\platform-tools"

Using Android Studio (Recommended)

Open Android Studio
File → Open and select android_client/ directory
Wait for Gradle sync to complete
Select "Build" → "Make Project"
APK will be generated in app/build/outputs/apk/debug/

Using Gradle (Command Line)

Linux/macOS:

cd android_client
./gradlew build

Windows:

cd android_client
gradlew.bat build

If you don't have Gradle installed system-wide, the wrapper will handle it.

Running

On Physical Device

Enable USB debugging on your Android device (Settings → Developer Options)
Connect via USB

Run:

./gradlew installDebug        # Linux/macOS
gradlew.bat installDebug      # Windows

App will be installed automatically
Launch "SCAR Chat" from your app drawer

On Emulator

Start Android Emulator from Android Studio (AVD Manager)
Wait for emulator to fully boot

Run:

./gradlew installDebug        # Linux/macOS
gradlew.bat installDebug      # Windows

App will be installed automatically
Launch "SCAR Chat" from emulator app drawer

Usage

Connect to Server:
- Enter server hostname (e.g., 192.168.1.100 or localhost)
- Enter port (default: 42317)
- Tap "Connect"
Chat:
- Go to "Chat" tab
- Type message in text field
- Tap "Send"
- View chat history in display area
Camera:
- Go to "Video" tab
- Select camera from dropdown (if multiple available)
- Check "Enable Camera" to start camera
- Server will receive CAMERA_ENABLE message
- Remote users will see camera status

Permissions

The app requires the following permissions (Android 6.0+):

INTERNET: Network communication with server
CAMERA: Camera access for video capture
RECORD_AUDIO: Audio recording capability

Permissions are requested at runtime on Android 6.0+.

Connection Protocol

Protocol: TLS/SSL over TCP
Port: 42317 (default)
Message Format: Text messages ending with newline (\n)
Camera Status: CAMERA_ENABLE / CAMERA_DISABLE messages

Dependencies

androidx.appcompat: Support library for backward compatibility
com.google.android.material: Material Design components
androidx.constraintlayout: Layout constraints
androidx.recyclerview: List/grid view components
androidx.viewpager2: Tab paging
org.bouncycastle: SSL/TLS support

Troubleshooting

Connection Failed

Verify server is running and accessible
Check hostname/IP and port number
Ensure firewall allows connection to port 42317
Check SSL certificate is valid (app accepts self-signed certs)

Camera Not Working

Verify camera permission is granted (Settings → Permissions)
Check device has a camera
Try reconnecting or restarting app

Build Errors

Update Android Studio to latest version
Run ./gradlew clean before rebuilding
Delete build/ and .gradle/ directories
Ensure Java JDK 11+ is installed

Security Notes

The app currently accepts self-signed SSL certificates (for development)
For production, implement proper certificate validation
Enable ProGuard/R8 obfuscation in release builds (configured)

Future Enhancements

Full video frame encoding/transmission (H.264)
Video frame decoding and display
Audio/VoIP support
Message persistence/history
User authentication
Emoji/sticker support
File transfer
Group chat support
Certificate pinning for enhanced security

Building APK for Distribution

cd android_client

# Create signed release build
./gradlew bundleRelease
# OR for APK
./gradlew assembleRelease

Output files:

AAB: app/build/outputs/bundle/release/app-release.aab
APK: app/build/outputs/apk/release/app-release.apk

License

Part of the SCAR Chat project. See main project README for details.