NotificationHandler.dart

Purpose

NotificationHandler.dart manages the logic for issuing notifications in the background. It uses flutter_local_notifications to alert the user when data collection intervals exceed expected limits, device behavior is abnormal, or battery status must be checked.

Imports

import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:flutter/services.dart';
import 'dart:convert';
import 'dart:async';
import 'StatusChecker.dart';
import 'dart:io';
import 'package:path_provider/path_provider.dart';

Used for:

  • Local notifications

  • File I/O

  • Checking system/device status

  • Persisting data

NotificationInfo Class

class NotificationInfo {
  String deviceName;
  int deviceIndex;
  String activityName;
  DateTime lastNotificationTime;
}

  • Stores information about each device’s last notification.

  • Prevents sending duplicate notifications too frequently.

NotificationHandler Class

class NotificationHandler {
  FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin;
  List<NotificationInfo> sentNotifications;
}

  • Manages all notifications using Flutter’s notification plugin.

  • Maintains a list of previously sent notifications to avoid redundancy.

Notification Intervals

int notification_IntervalMinutes_MMR_SensorFusion = 20;
int notification_IntervalMinutes_Sensoria = 20;
int notification_IntervalMinutes_SmartBand_HR = 100;
...

These intervals define the minimum time (in minutes) before a similar notification can be sent again for each device and metric.

Categorized Intervals:

  • MetaWear: Sensor Fusion, Temperature, Ambient Light, WriteFile, Battery

  • Sensoria: Motion/Battery/File

  • SmartBand: Heart Rate, Blood Pressure, Step Count

Functions (Not fully listed in preview but assumed)

  • sendNotification(...): Sends an alert to the user.

  • shouldNotify(...): Checks whether a notification should be sent based on time elapsed and previous records.

  • saveToFile(...) / loadFromFile(...): Manages persistence of sent notifications.

  • initializePlugin(): Likely sets up the plugin and notification channel.

Usage Context

Used in:

  • BackgroundHandling.dart as the default notification manager

  • BLE service status monitoring and alerts

  • Error reporting for data sensors

Notes

This system helps ensure the user is informed about sensor-related issues, like inactivity or battery drain, without being spammed repeatedly.