SmsAlarm

SmsAlarm is an Android app that watches incoming SMS-style notifications and plays a loud alarm when a target traffic message is detected.

Current detection rule: trigger when a new notification from an SMS app contains the text 上海交警.

Documentation

• Chinese full project documentation: docs/项目文档.md

What the app does

• Lets you toggle monitoring on/off from a single button in the main screen.
• Uses Android's Notification Listener API (not direct SMS read permissions) to inspect posted notification text.
• Filters likely SMS notification sources (Google Messages, AOSP MMS, or package names containing sms).
• Debounces alerts to avoid repeat triggers in a short interval.
• Starts a foreground alarm service that:
  • raises alarm/media volume to max,
  • requests audio focus,
  • loops res/raw/alarm.mp3,
  • shows an ongoing notification with a Stop Alarm action,
  • auto-stops after 10 minutes.
• Runs a low-priority foreground keep-alive service while monitoring is enabled.

Tech stack

• Kotlin + Android SDK
• minSdk 29 / targetSdk 34 / compileSdk 34
• AndroidX Core + AppCompat
• Gradle (Groovy DSL)

Project structure

• app/src/main/java/com/example/smsalarm/MainActivity.kt
  UI entry point, permission prompts, monitoring toggle.
• app/src/main/java/com/example/smsalarm/SmsNotificationListener.kt
  Notification listener and message matching logic.
• app/src/main/java/com/example/smsalarm/AlarmService.kt
  Foreground alarm playback and stop behavior.
• app/src/main/java/com/example/smsalarm/KeepAliveService.kt
  Foreground keep-alive notification/service.
• app/src/main/java/com/example/smsalarm/MonitorConfig.kt
  SharedPreferences-backed monitor enable/disable state.
• app/src/main/AndroidManifest.xml
  Permissions, services, listener declaration.

Permissions and system settings

The app requests / depends on:

• POST_NOTIFICATIONS
• FOREGROUND_SERVICE
• FOREGROUND_SERVICE_MEDIA_PLAYBACK
• FOREGROUND_SERVICE_DATA_SYNC
• MODIFY_AUDIO_SETTINGS
• WAKE_LOCK

It also requires manually enabling:

• Notification access for this app (Settings > Notification access) so SmsNotificationListener can receive notification events.

How alert triggering works

1. Monitoring must be enabled in the app.
2. A new notification is posted.
3. Notification package must look like an SMS app.
4. Notification text/body must contain 上海交警.
5. Debounce window check passes.
6. AlarmService starts as a foreground service and plays alarm audio.

Build and run

Prerequisites

• Android Studio Hedgehog+ (or compatible)
• Android SDK 34
• JDK 11

Debug build

./gradlew :app:assembleDebug

Install from Android Studio or with ADB:

adb install -r app/build/outputs/apk/debug/app-debug.apk

Release signing

app/build.gradle expects a keystore at ../smsalarm.keystore and reads credentials from environment variables:

• KEYSTORE_PASSWORD
• KEY_ALIAS
• KEY_PASSWORD

Then build:

./gradlew :app:assembleRelease

Versioning

versionCode is derived from Git commit count (git rev-list --count HEAD).

Note: shallow clones are rejected; fetch full history before building release/versioned artifacts.

Current limitations

• Keyword and package filtering are hardcoded.
• Debounce interval and play duration are currently fixed in code.
• UI is minimal (single toggle button).

Security and privacy notes

• The app inspects notification text delivered by Android's notification listener system.
• It does not currently upload message content anywhere in this project.
• Evaluate your local privacy/compliance requirements before production deployment.