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
• Statistics — summary cards, timeline charts, top apps, content type breakdown
• System app blocking — capture from selected apps disabled by default
• 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 LIKE with substring 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, backup/restore (SQLite), export (JSON, CSV)
SearchEngine.kt	LIKE substring search routing
QueryParser.kt	Natural language date & filter parsing
EncryptionManager.kt	Two-tier key derivation (Keystore → fallback)
ActivityTraceDatabase.kt	Room + SQLCipher setup
CaptureDao.kt	LIKE substring queries, insertAll, getAllItemKeys for import/CSV
RetentionCleanupWorker.kt	Configurable auto-delete via WorkManager
BackupImporter.kt	SQLite restore from backup (merge with dedup)
DataExporter.kt	JSON and CSV export
DatabaseExporter.kt	Plain SQLite backup (unencrypted)
ActivityTraceNotificationListener.kt	Notification capture service
AccessibilityCaptureService.kt	Screen capture via AccessibilityService
CaptureIngestor.kt	Unified capture pipeline (write to Room)
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