لماذا عند اغلاق البرنامج يتوقف عن جلب البيانات الى ال notification اريد حل 
الكود
import 'dart:async';
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:flutter_background/flutter_background.dart';
import 'package:http/http.dart' as http;

// إشعارات
final FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin =
    FlutterLocalNotificationsPlugin();

const AndroidNotificationChannel channel = AndroidNotificationChannel(
  'network_monitor_channel', // id
  'Network Monitor', // name
  description: 'قناة مراقبة حالة الشبكة',
  importance: Importance.high,
  ledColor: Color(0xFF3366FF),
  playSound: true,
  enableVibration: true,
);

Future<void> showNetworkNotification({
  required String title,
  required String body,
}) async {
  AndroidNotificationDetails androidDetails = AndroidNotificationDetails(
    channel.id,
    channel.name,
    channelDescription: channel.description,
    importance: Importance.high,
    priority: Priority.high,
    ticker: 'ticker',
    ongoing: true,
    autoCancel: false,
    icon: '@mipmap/ic_launcher',
    styleInformation: BigTextStyleInformation(''),
  );

  NotificationDetails notificationDetails = NotificationDetails(
    android: androidDetails,
  );

  await flutterLocalNotificationsPlugin.show(
    888,
    title,
    body,
    notificationDetails,
  );
}

Future<void> cancelNetworkNotification() async {
  await flutterLocalNotificationsPlugin.cancel(888);
}

class DashboardScreen extends StatefulWidget {
  final String username;

  const DashboardScreen({Key? key, required this.username}) : super(key: key);

  @override
  State<DashboardScreen> createState() => _DashboardScreenState();
}

class _DashboardScreenState extends State<DashboardScreen> {
  Timer? _timer;
  Map<String, dynamic> _currentUserData = {
    'ip': '...',
    'mac': '...',
    'bytes_in': '0',
    'bytes_out': '0',
    'remain_bytes_total': '0',
    'uptime': '0s',
    'session_time_left': 'غير محدود',
  };

  @override
  void initState() {
    super.initState();
    _initializeBackground();
    _initializeNotifications();
    _startPeriodicFetch();
  }

  Future<void> _initializeBackground() async {
    final androidConfig = FlutterBackgroundAndroidConfig(
      notificationTitle: "Network Monitor",
      notificationText: "سيتم تحديث بيانات الشبكة في الخلفية",
      notificationImportance: AndroidNotificationImportance.high,
      notificationIcon: AndroidResource(name: 'ic_launcher', defType: 'mipmap'),
    );

    bool success = await FlutterBackground.initialize(
      androidConfig: androidConfig,
    );

    if (success) {
      await FlutterBackground.enableBackgroundExecution();
    }
  }

  Future<void> _initializeNotifications() async {
    // تهيئة القناة - حتى تعمل الإشعارات بشكل صحيح للأندرويد 8+
    await flutterLocalNotificationsPlugin
        .resolvePlatformSpecificImplementation<
          AndroidFlutterLocalNotificationsPlugin
        >()
        ?.createNotificationChannel(channel);

    const AndroidInitializationSettings androidSettings =
        AndroidInitializationSettings('@mipmap/ic_launcher');

    const InitializationSettings initSettings = InitializationSettings(
      android: androidSettings,
    );

    await flutterLocalNotificationsPlugin.initialize(initSettings);
  }

  void _startPeriodicFetch() {
    _timer?.cancel();
    _timer = Timer.periodic(const Duration(seconds: 1), (_) => _fetchStatus());
    _fetchStatus();
  }

  @override
  void dispose() {
    _timer?.cancel();
    cancelNetworkNotification();
    FlutterBackground.disableBackgroundExecution();
    super.dispose();
  }

  Future<void> _fetchStatus() async {
    try {
      final res = await http
          .get(Uri.parse('http://172.16.0.1/status?var=json'))
          .timeout(const Duration(seconds: 1));

      if (res.statusCode == 200) {
        final data = json.decode(res.body);
        if (data.containsKey('errors')) {
          await cancelNetworkNotification();
          return;
        }

        setState(() {
          _currentUserData = {
            'ip': data['ip'] ?? 'غير معروف',
            'mac': data['mac']?.replaceAll('%3A', ':') ?? 'غير معروف',
            'bytes_in': _formatBytes(data['bytes_in']?.toString() ?? '0'),
            'bytes_out': _formatBytes(data['bytes_out']?.toString() ?? '0'),
            'remain_bytes_total': _formatBytes(
              data['remain_bytes_total']?.toString() ?? '0',
            ),
            'uptime': _formatUptimeExtended(data['uptime'] ?? '0s'),
            'session_time_left': _formatSessionTimeLeft(
              data['session_time_left'] ?? 'غير محدود',
            ),
          };
        });

        await showNetworkNotification(
          title: "حالة الشبكة - ${widget.username}",
          body: _buildNotificationBody(_currentUserData),
        );
      } else {
        await cancelNetworkNotification();
      }
    } catch (_) {
      await cancelNetworkNotification();
    }
  }

  String _formatBytes(String bytes) {
    try {
      final value = int.parse(bytes);
      if (value < 1024) return '$value بايت';
      if (value < 1024 * 1024)
        return '${(value / 1024).toStringAsFixed(1)} كيلوبايت';
      if (value < 1024 * 1024 * 1024)
        return '${(value / (1024 * 1024)).toStringAsFixed(1)} ميجابايت';
      return '${(value / (1024 * 1024 * 1024)).toStringAsFixed(1)} جيجابايت';
    } catch (_) {
      return bytes;
    }
  }

  String _formatUptimeExtended(String uptime) {
    final regex = RegExp(r'(?:(\d+)d)?(?:(\d+)h)?(?:(\d+)m)?(?:(\d+)s)?');
    final match = regex.firstMatch(uptime);
    if (match == null) return uptime;

    final days = int.tryParse(match.group(1) ?? '0') ?? 0;
    final hours = int.tryParse(match.group(2) ?? '0') ?? 0;
    final minutes = int.tryParse(match.group(3) ?? '0') ?? 0;
    final seconds = int.tryParse(match.group(4) ?? '0') ?? 0;

    String result = '';
    if (days > 0) result += '$days يوم ';
    if (hours > 0) result += '$hours ساعة ';
    if (minutes > 0) result += '$minutes دقيقة ';
    if (seconds > 0) result += '$seconds ثانية';

    return result.trim();
  }

  String _formatSessionTimeLeft(String sessionTimeLeft) {
    if (sessionTimeLeft == 'غير محدود') return sessionTimeLeft;
    return _formatUptimeExtended(sessionTimeLeft);
  }

  Future<void> _logout() async {
    try {
      final response = await http
          .post(
            Uri.parse('http://172.16.0.1/logout'),
            headers: {'Content-Type': 'application/x-www-form-urlencoded'},
            body: {'username': widget.username},
          )
          .timeout(const Duration(seconds: 5));

      if (response.statusCode == 200 && mounted) {
        await cancelNetworkNotification();
        FlutterBackground.disableBackgroundExecution();
        Navigator.of(context).pop(); // أو طريقة الخروج المناسبة
      } else {
        throw Exception('فشل في تسجيل الخروج');
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('حدث خطأ: ${e.toString()}'),
            backgroundColor: Colors.red,
            behavior: SnackBarBehavior.floating,
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(10),
            ),
          ),
        );
      }
    }
  }

  String _buildNotificationBody(Map<String, dynamic> data) {
    return 'مدة الاتصال: ${data['uptime']}\n'
        'المستلم: ${data['bytes_in']}\n'
        'المرسل: ${data['bytes_out']}\n'
        'الوقت المتبقي: ${data['session_time_left']}\n'
        'المتبقي: ${data['remain_bytes_total']}\n'
        'حالة الاتصال: نشط';
  }

  @override
  Widget build(BuildContext context) {
    return Directionality(
      textDirection: TextDirection.rtl,
      child: Scaffold(
        backgroundColor: const Color(0xFFF8FAFD),
        appBar: AppBar(
          title: const Text('لوحة التحكم'),
          actions: [
            IconButton(
              icon: const Icon(Icons.logout_rounded),
              tooltip: 'تسجيل الخروج',
              onPressed: _logout,
            ),
          ],
        ),
        body: SafeArea(
          child: SingleChildScrollView(
            padding: const EdgeInsets.all(16),
            child: Column(
              children: [
                _buildUserCard(),
                const SizedBox(height: 24),
                GridView.count(
                  shrinkWrap: true,
                  physics: const NeverScrollableScrollPhysics(),
                  crossAxisCount: 2,
                  childAspectRatio: 1.1,
                  crossAxisSpacing: 16,
                  mainAxisSpacing: 16,
                  children: [
                    _buildStatCard(
                      icon: Icons.timer_rounded,
                      title: 'مدة الاتصال',
                      value: _currentUserData['uptime'],
                      color: const Color(0xFF3366FF),
                    ),
                    _buildStatCard(
                      icon: Icons.download_rounded,
                      title: 'البيانات المستلمة',
                      value: _currentUserData['bytes_in'],
                      color: const Color(0xFF00C1D4),
                    ),
                    _buildStatCard(
                      icon: Icons.upload_rounded,
                      title: 'البيانات المرسلة',
                      value: _currentUserData['bytes_out'],
                      color: const Color(0xFFFF8A34),
                    ),
                    _buildStatCard(
                      icon: Icons.access_time_filled_rounded,
                      title: 'الوقت المتبقي',
                      value: _currentUserData['session_time_left'],
                      color: const Color(0xFF50B83C),
                    ),
                    _buildStatCard(
                      icon: Icons.data_usage_rounded,
                      title: 'البيانات المتبقية',
                      value: _currentUserData['remain_bytes_total'],
                      color: const Color(0xFF9C6ADE),
                    ),
                    _buildStatCard(
                      icon: Icons.network_check_rounded,
                      title: 'حالة الاتصال',
                      value: 'نشط',
                      color: const Color(0xFFF7C948),
                    ),
                  ],
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }

  Widget _buildUserCard() {
    return Container(
      decoration: BoxDecoration(
        borderRadius: BorderRadius.circular(16),
        color: Colors.white,
        boxShadow: [
          BoxShadow(
            color: Colors.grey.withOpacity(0.1),
            blurRadius: 10,
            offset: const Offset(0, 5),
          ),
        ],
      ),
      padding: const EdgeInsets.all(16),
      child: Column(
        children: [
          Row(
            children: [
              Container(
                width: 60,
                height: 60,
                decoration: BoxDecoration(
                  color: const Color(0xFF3366FF).withOpacity(0.1),
                  shape: BoxShape.circle,
                ),
                child: const Icon(
                  Icons.person_rounded,
                  size: 30,
                  color: Color(0xFF3366FF),
                ),
              ),
              const SizedBox(width: 16),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      widget.username,
                      style: const TextStyle(
                        fontSize: 18,
                        fontWeight: FontWeight.bold,
                        fontFamily: 'Tajawal',
                        color: Color(0xFF2E384D),
                      ),
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                    ),
                    const SizedBox(height: 4),
                    const Text(
                      'بيانات المستخدم',
                      style: TextStyle(
                        fontSize: 14,
                        color: Color(0xFF8798AD),
                        fontFamily: 'Tajawal',
                      ),
                    ),
                  ],
                ),
              ),
            ],
          ),
          const SizedBox(height: 16),
          Divider(color: Colors.grey.withOpacity(0.2), height: 1),
          const SizedBox(height: 12),
          _buildInfoRow(
            Icons.wifi_rounded,
            'عنوان IP:',
            _currentUserData['ip'],
            const Color(0xFF2E384D),
          ),
          _buildInfoRow(
            Icons.device_hub_rounded,
            'عنوان MAC:',
            _currentUserData['mac'],
            const Color(0xFF2E384D),
          ),
        ],
      ),
    );
  }

  Widget _buildInfoRow(IconData icon, String label, String value, Color color) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 8),
      child: Row(
        children: [
          Icon(icon, size: 20, color: color.withOpacity(0.6)),
          const SizedBox(width: 12),
          Text(
            label,
            style: TextStyle(
              fontWeight: FontWeight.bold,
              fontFamily: 'Tajawal',
              fontSize: 15,
              color: color.withOpacity(0.8),
            ),
          ),
          const SizedBox(width: 8),
          Expanded(
            child: Text(
              value,
              style: TextStyle(
                color: color,
                overflow: TextOverflow.ellipsis,
                fontFamily: 'Tajawal',
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildStatCard({
    required IconData icon,
    required String title,
    required String value,
    required Color color,
  }) {
    return Container(
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(16),
        boxShadow: [
          BoxShadow(
            color: Colors.grey.withOpacity(0.1),
            blurRadius: 10,
            offset: const Offset(0, 5),
          ),
        ],
      ),
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Container(
              padding: const EdgeInsets.all(10),
              decoration: BoxDecoration(
                color: color.withOpacity(0.1),
                borderRadius: BorderRadius.circular(12),
              ),
              child: Icon(icon, size: 24, color: color),
            ),
            const SizedBox(height: 12),
            Text(
              value,
              style: const TextStyle(
                fontFamily: 'Tajawal',
                fontSize: 16,
                fontWeight: FontWeight.bold,
                color: Color(0xFF2E384D),
              ),
            ),
            const SizedBox(height: 4),
            Text(
              title,
              style: const TextStyle(
                fontFamily: 'Tajawal',
                fontSize: 13,
                color: Color(0xFF8798AD),
              ),
            ),
          ],
        ),
      ),
    );
  }
}