Activity Trace

On-device cross-app memory search for Android. No AI, no cloud, no internet permission.

Search across notifications, accessibility screen captures, and indexed files with natural language — all encrypted at rest with SQLCipher AES-256-CBC + Android Keystore.

Features

• Search anything — notifications, screen captures, indexed files
• Natural language queries — yesterday, last week, in:signal, type:notification
• Prefix & wildcard search — test matches testing/tested, *error matches fatal error
• Search term highlighting — matched keywords highlighted in results
• Full encryption — SQLCipher + Android Keystore (StrongBox on capable hardware)
• Zero-network — no internet permission, no telemetry, no cloud
• Open source — GPL-3.0-only, distributed via F-Droid

Architecture

Layer	Technology
UI	Jetpack Compose + Material 3 (dynamic color)
Architecture	Single-Activity, ViewModel, reactive Flows
Storage	Room + SQLCipher (AES-256-CBC, arm64-v8a only)
Search	SQLite FTS5 with prefix matching
Capture	NotificationListener, AccessibilityService, File indexing (SAF)
Retention	WorkManager (configurable periodic cleanup)

Min SDK: 26 (Android 8.0) · Target SDK: 36

Screenshots

Build

./gradlew assembleDebug     # debug build (unminified)
./gradlew assembleRelease   # release build (minified, ProGuard)

./gradlew test               # unit tests
./gradlew lint               # static analysis
./gradlew connectedDebugAndroidTest  # instrumentation tests

Prerequisites

• Android Studio Hedgehog (2023.1.1) or later
• JDK 17
• Android SDK 36

Dependencies

• Compose BOM 2024.01.00 — Material 3, dynamic color
• Room 2.6.1 + KSP — type-safe SQLite
• WorkManager 2.9.0 — background retention cleanup
• SQLCipher 4.5.4 — encrypted database at rest
• MockK 1.13.9 — test mocking
• Turbine 1.0.0 — Flow testing

See gradle/libs.versions.toml for the full catalog.

Key files

File	Purpose
MainActivity.kt	Entry point, onboarding & settings routing
SearchScreen.kt	Main search UI with prefix/wildcard matching
SearchViewModel.kt	Reactive search pipeline (flatMapLatest)
SettingsScreen.kt	Permissions, retention, database export
SearchEngine.kt	FTS5 + LIKE search routing
QueryParser.kt	Natural language date & filter parsing
EncryptionManager.kt	Two-tier key derivation (Keystore → fallback)
ActivityTraceDatabase.kt	Room + SQLCipher + FTS5 setup
CaptureDao.kt	FTS5 MATCH + LIKE queries
RetentionCleanupWorker.kt	Configurable auto-delete via WorkManager
ActivityTraceNotificationListener.kt	Notification capture service
AccessibilityCaptureService.kt	Screen capture via AccessibilityService
CaptureIngestor.kt	Unified capture pipeline (write to Room + FTS5)
PendingIntentSerializer.kt	Notification deep link serialization (Parcel ↔ Base64)
FileIndexer.kt	SAF directory walk + PDF text extraction
FileIndexingWorker.kt	Background file indexing (daily / manual)

Privacy

Activity Trace is designed to be zero-trust by default:

• No internet permission in the manifest
• No telemetry, no analytics, no crash reporting
• All data encrypted at rest with SQLCipher + Android Keystore
• F-Droid only — no proprietary dependencies, no Google Play Services

License

GNU General Public License v3.0 only. See LICENSE.

Contributing

Contributions are welcome. Please open an issue first to discuss changes.

• Run ./gradlew test before submitting
• Maintain the GPL-3.0-only license
• No AI/ML dependencies, no cloud features, no Play Services