Signal Android - Deploy and Usage Guide

Prerequisites

Development Environment

Android Studio (latest stable version recommended)
Android SDK with API level 21+ (minimum supported)
Java Development Kit (JDK) 11 or later
Kotlin (included with Android Studio)
Git for version control

System Requirements

Minimum 8GB RAM (16GB recommended for emulator testing)
Minimum 4GB free disk space
Android device or emulator running Android 5.0 (API 21) or higher

Optional Dependencies

Android NDK (if building native components)
Firebase SDK (for push notifications)
Google Play Services (for certain features)

Installation

1. Clone the Repository

git clone https://github.com/signalapp/Signal-Android.git
cd Signal-Android

2. Import into Android Studio

Open Android Studio
Select "Open an existing project"
Navigate to the cloned directory and select it
Wait for Gradle sync to complete

3. Build Dependencies

Android Studio will automatically download required dependencies via Gradle. If you need to manually sync:

./gradlew build

Configuration

1. API Keys and Services

Signal requires several API keys for full functionality:

Google Play Services

Create a project in Google Cloud Console
Enable required APIs (Maps, Firebase, etc.)
Download google-services.json and place in app/ directory

Firebase Configuration

Create a Firebase project
Add Android app with package name: org.thoughtcrime.securesms
Download google-services.json to app/ directory

Optional: Push Notifications

For push notification functionality, you'll need:

Firebase Cloud Messaging (FCM) configuration
Server-side push notification setup

2. Build Variants

Signal supports multiple build variants:

debug - Development builds
release - Production builds
beta - Beta release builds

Configure in app/build.gradle:

buildTypes {
    debug {
        // Debug-specific configuration
    }
    release {
        // Release-specific configuration
    }
}

Build & Run

1. Building for Development

# Build debug APK
./gradlew assembleDebug

# Build debug APK with tests
./gradlew assembleDebug connectedDebugAndroidTest

# Install to connected device
./gradlew installDebug

2. Running on Device/Emulator

Connect an Android device via USB with USB debugging enabled
Or create an emulator in Android Studio (API 21+)
Select the device/emulator from the run configuration dropdown
Click the "Run" button (green play icon)

3. Building for Production

# Build release APK
./gradlew assembleRelease

# Build release APK with tests
./gradlew assembleRelease connectedReleaseAndroidTest

4. Signing Configuration

For release builds, configure signing in app/build.gradle:

signingConfigs {
    release {
        storeFile file("path/to/keystore")
        storePassword "your_password"
        keyAlias "your_alias"
        keyPassword "your_password"
    }
}

Deployment

1. Google Play Store

Create a Google Play Developer account
Create a new application listing
Upload the signed APK from app/build/outputs/apk/release/
Complete store listing and pricing information
Submit for review

2. Alternative Distribution

For non-Play Store distribution:

# Generate signed APK
./gradlew assembleRelease

# Output will be in:
# app/build/outputs/apk/release/app-release.apk

3. Beta Testing

Signal supports beta testing through Google Play:

Subscribe to beta releases: https://play.google.com/apps/testing/org.thoughtcrime.securesms
Upload beta APKs to the Play Console
Manage beta testers through the Play Console

Troubleshooting

Common Build Issues

1. Gradle Sync Failed

Issue: Gradle sync fails with dependency errors Solution:

# Clear Gradle cache
./gradlew clean

# Sync again
./gradlew build

2. API Level Mismatch

Issue: Build fails due to API level incompatibility Solution:

Check compileSdkVersion in app/build.gradle
Ensure Android SDK is installed for that API level
Update minSdkVersion if needed (minimum is 21)

3. Out of Memory Errors

Issue: Build fails with Java heap space errors Solution:

Increase heap size in gradle.properties:

org.gradle.jvmargs=-Xmx4096m -XX:MaxPermSize=512m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8

Runtime Issues

1. App Crashes on Startup

Issue: App crashes immediately after launch Solution:

Check logcat for error messages
Verify all required permissions are granted
Ensure proper API keys are configured

2. Push Notifications Not Working

Issue: Messages don't arrive in real-time Solution:

Verify Firebase configuration
Check internet connectivity
Ensure battery optimization is disabled for the app

3. Database Migration Issues

Issue: Database schema conflicts during updates Solution:

Clear app data and cache
Check migration scripts in app/src/main/java/org/thoughtcrime/securesms/database/
Ensure proper versioning in SignalDatabase

Development Workflow

1. Contributing Code

Fork the repository
Create a feature branch
Make changes following the CONTRIBUTING.md
Submit a pull request

2. Testing

# Run unit tests
./gradlew test

# Run instrumented tests
./gradlew connectedAndroidTest

3. Code Quality

Signal uses several code quality tools:

Detekt for Kotlin linting
Spotless for code formatting
Ktlint for style consistency

Run quality checks:

./gradlew detekt
./gradlew spotlessCheck

Security Considerations

1. Cryptography Notice

Signal includes cryptographic software. Check your country's laws regarding encryption software before use.

2. Key Management

Never commit API keys to version control
Use secure key storage for production builds
Rotate keys regularly for production deployments

3. Privacy Features

Signal includes advanced privacy features:

Sealed sender mode
Disappearing messages
Screen security
Incognito keyboard

Ensure these features are properly configured for your deployment scenario.

How to Deploy & Use WhisperSystems/Signal-Android