SensorService.java

Purpose

The SensorService is an Android Service class designed to run sensor-related background tasks in a persistent foreground mode. It primarily initializes and manages the MetaWearHandler to keep data streaming alive during app backgrounding.

Features & Responsibilities

  • Runs independently of Flutter UI as a long-lived background process.

  • Handles localization dynamically based on language settings passed via Intent.

  • Starts in the foreground with a persistent notification to prevent termination.

  • Verifies permission status (e.g. ACCESS_FINE_LOCATION) on startup.

Initialization

@Override
public void onCreate() {
    super.onCreate();
    metaWearHandler = new MetaWearHandler(this, null);
}

Initializes the MetaWearHandler when the service is created.

Start Command Logic

@Override
public int onStartCommand(Intent intent, int flags, int startId)

Handles:

  • Language switching via LANGUAGE_CODE intent extra.

  • Permission check: If ACCESS_FINE_LOCATION is not granted, the service stops itself.

  • Updates the app’s locale dynamically if the language is provided.

Foreground Notification

The method startForegroundServiceWithNotification():

  • Creates a NotificationChannel

  • Builds and launches a persistent notification using NotificationCompat

  • Prevents Android from force-killing the background process

This is essential for uninterrupted sensor operations.

Language Localization

If LANGUAGE_CODE is provided via intent:

Locale locale = new Locale(languageCode);
Locale.setDefault(locale);
Configuration config = new Configuration();
config.setLocale(locale);

Updates the application’s configuration to use the desired language.

Lifecycle Overrides

  • onBind() returns null as this is a started service.

  • onDestroy() provides cleanup hooks (though none are implemented).

Integration

  • Designed to integrate tightly with MetaWearHandler.java

  • Used in scenarios where BLE sensors must stream data continuously even when the app is backgrounded.

Best Practices

  • Handles runtime permission validation safely.

  • Starts foreground notification for Android 8+ compliance.

  • Avoids binding; focuses on self-contained execution for background data acquisition.

Dependencies

  • MetaWearHandler

  • Android Service, Notification, Locale, and BLE permission classes