generic_audio_notification

A Flutter package for Android that plays looping background audio when a Firebase Cloud Messaging (FCM) push notification is received. Perfect for critical alerts that require continuous audio playback until user interaction.

🎯 Features

• ✅ Android-only support (API 26+)
• ✅ Looping audio playback via Android Foreground Service
• ✅ Configurable loop behavior - play once or loop continuously
• ✅ Works in foreground, background, and terminated states
• ✅ Audio stops when user taps notification or opens app
• ✅ Data-only FCM messages (no notification payload needed)
• ✅ Custom notification display
• ✅ Fully reusable package with example app

📋 Requirements

• Flutter SDK
• Android SDK (minSdk 26 / Android 8.0+)
• Firebase project with FCM enabled
• google-services.json configured

📦 Installation

Add to your pubspec.yaml:

dependencies:
  generic_audio_notification: ^1.0.0
  firebase_messaging: ^14.7.10
  firebase_core: ^2.24.2

Run:

flutter pub get

🔧 Setup

1. Android Configuration

The package automatically adds required permissions and service declarations. Verify your android/app/src/main/AndroidManifest.xml includes:

<uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
<uses-permission android:name="android.permission.FOREGROUND_SERVICE_MEDIA_PLAYBACK" />
<uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
<uses-permission android:name="android.permission.INTERNET" />

2. Firebase Setup

1. Add your google-services.json to android/app/
2. Add google-services plugin to android/settings.gradle:

plugins {
    id "com.google.gms.google-services" version "4.4.0" apply false
}

3. Apply plugin in android/app/build.gradle:

plugins {
    id "com.google.gms.google-services"
}

3. Initialize Firebase

import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:generic_audio_notification/generic_audio_notification.dart';

// Background message handler
@pragma('vm:entry-point')
Future<void> _firebaseMessagingBackgroundHandler(RemoteMessage message) async {
  if (message.data['music_url'] != null) {
    final audio = GenericAudioNotification();
    await audio.startAudio(
      message.data['music_url'],
      title: message.data['title'] ?? 'Alert',
      body: message.data['body'] ?? 'Tap to stop',
      icon: 'mipmap/ic_launcher',
    );
  }
}

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  
  // Register background handler
  FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);
  
  runApp(MyApp());
}

📱 Usage

Get FCM Token

final token = await FirebaseMessaging.instance.getToken();
print('FCM Token: $token');

Send FCM Message

Send a data-only message (no notification object) with high priority:

{
  "message": {
    "token": "YOUR_DEVICE_TOKEN",
    "data": {
      "music_url": "https://example.com/audio.mp3",
      "title": "Critical Alert",
      "body": "Tap to stop audio",
      "should_loop": "true"
    },
    "android": {
      "priority": "high"
    }
  }
}

Important:

• Use data-only messages (no notification payload)
• Set android.priority to "high" for background delivery
• music_url must be a publicly accessible URL
• should_loop controls playback: "true" for continuous loop (default), "false" for single playback

Stop Audio

await GenericAudioNotification().stopAudio();

🎬 How It Works

Message Flow

1. FCM Message Received → Background handler triggered
2. Audio Service Started → Foreground service with notification
3. Audio Loops → Continuous playback until interaction
4. User Taps Notification → App opens, audio stops
5. User Opens App → Audio stops automatically

App States

State	Handler	Audio Playback
Foreground	Background handler (Android)	✅ Works
Background	Background handler	✅ Works
Terminated	Background handler	✅ Works

📝 FCM Payload Format

Required Fields

• music_url (String): URL to audio file
• title (String): Notification title
• body (String): Notification body

Optional Fields

• should_loop (String): "true" to loop continuously (default), "false" to play once

Example cURL Request

curl -X POST https://fcm.googleapis.com/v1/projects/YOUR_PROJECT/messages:send \
  -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "message": {
      "token": "DEVICE_TOKEN",
      "data": {
        "music_url": "https://www.soundhelix.com/examples/mp3/SoundHelix-Song-1.mp3",
        "title": "Emergency Alert",
        "body": "Tap to acknowledge"
      },
      "android": {
        "priority": "high"
      }
    }
  }'

🐛 Troubleshooting

Audio Not Playing

1. Check logs for error messages
2. Verify music_url is publicly accessible
3. Ensure FCM message has android.priority: "high"
4. Confirm app has notification permissions

Notification Not Showing

1. Check notification permissions are granted
2. Verify Foreground Service is running (check logs)
3. Test with Simulate Alert button in example app

📚 Example App

The package includes a complete example app demonstrating:

• FCM token display with copy button
• Foreground/background message handling
• Notification tap handling
• Audio playback simulation

Run the example:

cd example
flutter run

🔍 Logging

The package provides comprehensive logging for debugging:

• 🔧 Setup messages
• 📱 Message received
• ▶️ Audio playback started
• 🛑 Audio stopped
• ✅ Success confirmations
• ⚠️ Warnings

Enable verbose logging in your app to see all events.

⚖️ License

MIT License - see LICENSE file for details.

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

📧 Support

For issues and feature requests, please use the GitHub issue tracker.

🙏 Credits

Created by Your Name

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Note: This package is Android-only. iOS support is not planned as iOS has strict background audio limitations.