SensoriaApi.dart

Purpose 

SensoriaApi.dart acts as a communication interface between the Flutter app and the native platform layer for Sensoria wearable BLE devices. It manages sensor connection, disconnection, data monitoring, and listens for connection status updates.

Imports 

import 'package:flutter/services.dart';
import 'package:geolocator/geolocator.dart';
import 'package:flutter_reactive_ble/flutter_reactive_ble.dart';
import 'package:fluttertoast/fluttertoast.dart';
import 'package:permission_handler/permission_handler.dart';
import '../enums/device_connection_status.dart';
import 'dart:io';

Platform communication: flutter/services
BLE: flutter_reactive_ble
Location: geolocator
Permissions: permission_handler
App-defined enum: device_connection_status

Platform Channels 

static const MethodChannel _platform = MethodChannel('com.example.healthywear/sensoria');
static const _connectionStatusChannel = EventChannel('com.example.healthywear/sensoria_connection_status');

MethodChannel: Communicates with native methods.
EventChannel: Receives connection status broadcasts from native side.

Internal State & Callbacks 

static bool _alreadyListening = false;
static String _languageCode = '';
static Function(String, int, DeviceConnectionStatus)? onConnectionStatusChanged;

Tracks if BLE event listener is already attached.
Stores language code for context-specific messages.
Holds reference to the event status callback.

Setting the Connection Listener 

static void setConnectionStatusListener(Function(String, int, DeviceConnectionStatus) callback) {
  onConnectionStatusChanged = callback;
}

External components can register a callback for connection status updates.

Event Stream Listener 

if (!_alreadyListening) {
  _connectionStatusChannel.receiveBroadcastStream().listen((event) {
    final decoded = json.decode(event);
    final deviceId = decoded['deviceId'];
    final index = decoded['index'];
    final status = DeviceConnectionStatus.values[decoded['status']];
    onConnectionStatusChanged?.call(deviceId, index, status);
  });
  _alreadyListening = true;
}

Listens for native broadcast events, parses them, and calls the connection status callback.

Native Method Wrappers 

Each method below delegates its work to native code via the MethodChannel.

`connectToDevice`

await _platform.invokeMethod('connect', {
  'id': id,
  'index': index,
  'languageCode': languageCode,
});

Establishes a BLE connection with the specified Sensoria device.

`disconnectFromDevice`

await _platform.invokeMethod('disconnect', {'id': id});

Disconnects the BLE connection.

`vibrate`

await _platform.invokeMethod('vibrate', {
  'id': id,
  'intensity': intensity,
});

Triggers haptic feedback on the device.

`startMonitoring` and `stopMonitoring`

await _platform.invokeMethod('startMonitoring', {'id': id});
await _platform.invokeMethod('stopMonitoring', {'id': id});

Controls data streaming from the device.

Dependencies 

Native platform implementations for:
- connect, disconnect, vibrate, startMonitoring, stopMonitoring
Correct permissions for Bluetooth, location, and background execution
DeviceConnectionStatus enum for application-wide BLE state tracking