Network Interceptor for noticeboard mobile (#35)

* Bump up IOS version to 12 , added network interceptor in list_notices screen

* Added network interceptor to all reqd widgets

* Add Pranav to contributors.md

* Added root context to the stream so that it is always mounted

* Fix flutter analyze, removed deprecated willpopscope

* Added dynamic fetch when back online

All changes are as follows:
I have updated the web view flutter package to 4.7.0 and upgraded
flutter version to 3.19 because reloading the webview requires a webview
controller, also added another stream for this purpose

* Added EOF in enums, removed build files

CONTRIBUTORS.md

@@ -1,3 +1,4 @@
 - [@Sparsh1212](https://github.com/Sparsh1212)
 - [@just-ary27](https://github.com/just-ary27)
-- [@kmrinal19](https://github.com/kmrinal19)
+- [@kmrinal19](https://github.com/kmrinal19)
+- [@pranavkonidena](https://github.com/pranavkonidena)

noticeboard/ios/.gitignore

@@ -24,6 +24,7 @@ Flutter/flutter_assets/
 Flutter/flutter_export_environment.sh
 ServiceDefinitions.json
 Runner/GeneratedPluginRegistrant.*
+build/
 
 # Exceptions to above rules.
 !default.mode1v3

noticeboard/ios/Flutter/AppFrameworkInfo.plist

@@ -21,6 +21,6 @@
   <key>CFBundleVersion</key>
   <string>1.0</string>
   <key>MinimumOSVersion</key>
-  <string>9.0</string>
+  <string>12.0</string>
 </dict>
 </plist>

noticeboard/ios/Podfile

@@ -1,5 +1,5 @@
 # Uncomment this line to define a global platform for your project
- platform :ios, '10.0'
+ platform :ios, '12.0'
 
 # CocoaPods analytics sends network stats synchronously affecting flutter build latency.
 ENV['COCOAPODS_DISABLE_STATS'] = 'true'

noticeboard/ios/Podfile.lock

@@ -7,7 +7,7 @@ PODS:
   - firebase_core (2.24.2):
     - Firebase/CoreOnly (= 10.18.0)
     - Flutter
-  - firebase_messaging (14.7.9):
+  - firebase_messaging (14.7.10):
     - Firebase/Messaging (= 10.18.0)
     - firebase_core
     - Flutter
@@ -119,23 +119,23 @@ EXTERNAL SOURCES:
 SPEC CHECKSUMS:
   Firebase: 414ad272f8d02dfbf12662a9d43f4bba9bec2a06
   firebase_core: 0af4a2b24f62071f9bf283691c0ee41556dcb3f5
-  firebase_messaging: 875385354f623750aa03204a028d640108bc3412
+  firebase_messaging: 90e8a6db84b6e1e876cebce4f30f01dc495e7014
   FirebaseCore: 2322423314d92f946219c8791674d2f3345b598f
   FirebaseCoreInternal: b444828ea7cfd594fca83046b95db98a2be4f290
   FirebaseInstallations: 033d199474164db20c8350736842a94fe717b960
   FirebaseMessaging: 9bc34a98d2e0237e1b121915120d4d48ddcf301e
-  Flutter: f04841e97a9d0b0a8025694d0796dd46242b2854
+  Flutter: e0871f40cf51350855a761d2e70bf5af5b9b5de7
   flutter_secure_storage: 23fc622d89d073675f2eaa109381aefbcf5a49be
   GoogleDataTransport: 57c22343ab29bc686febbf7cbb13bad167c2d8fe
   GoogleUtilities: 0759d1a57ebb953965c2dfe0ba4c82e95ccc2e34
   nanopb: d4d75c12cd1316f4a64e3c6963f879ecd4b5e0d5
-  path_provider_foundation: 29f094ae23ebbca9d3d0cec13889cd9060c0e943
+  path_provider_foundation: 3784922295ac71e43754bd15e0653ccfd36a147c
   PromisesObjC: c50d2056b5253dadbd6c2bea79b0674bd5a52fa4
   share_plus: c3fef564749587fc939ef86ffb283ceac0baf9f5
   uni_links: d97da20c7701486ba192624d99bffaaffcfc298a
-  url_launcher_ios: bf5ce03e0e2088bad9cc378ea97fa0ed5b49673b
-  webview_flutter_wkwebview: b7e70ef1ddded7e69c796c7390ee74180182971f
+  url_launcher_ios: bbd758c6e7f9fd7b5b1d4cde34d2b95fcce5e812
+  webview_flutter_wkwebview: be0f0d33777f1bfd0c9fdcb594786704dbf65f36
 
-PODFILE CHECKSUM: f3c6bbf2cd440a5be9eae241d089fc1e5c9e4ade
+PODFILE CHECKSUM: 7b33e402635c950b38d380dc47108a3f46f265c2
 
 COCOAPODS: 1.14.3

noticeboard/ios/Runner.xcodeproj/project.pbxproj

@@ -158,7 +158,7 @@
 		97C146E61CF9000F007C117D /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
-				LastUpgradeCheck = 1430;
+				LastUpgradeCheck = 1510;
 				ORGANIZATIONNAME = "";
 				TargetAttributes = {
 					97C146ED1CF9000F007C117D = {
@@ -346,7 +346,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 11.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				ONLY_ACTIVE_ARCH = NO;
 				SDKROOT = iphoneos;
@@ -372,7 +372,7 @@
 				INFOPLIST_FILE = Runner/Info.plist;
 				INFOPLIST_KEY_CFBundleDisplayName = Noticeboard;
 				INFOPLIST_KEY_LSApplicationCategoryType = "public.app-category.education";
-				IPHONEOS_DEPLOYMENT_TARGET = 11.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -436,7 +436,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 11.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
 				MTL_ENABLE_DEBUG_INFO = YES;
 				ONLY_ACTIVE_ARCH = NO;
 				SDKROOT = iphoneos;
@@ -485,7 +485,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 11.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				ONLY_ACTIVE_ARCH = YES;
 				SDKROOT = iphoneos;
@@ -512,7 +512,7 @@
 				INFOPLIST_FILE = Runner/Info.plist;
 				INFOPLIST_KEY_CFBundleDisplayName = Noticeboard;
 				INFOPLIST_KEY_LSApplicationCategoryType = "public.app-category.education";
-				IPHONEOS_DEPLOYMENT_TARGET = 11.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -546,7 +546,7 @@
 				INFOPLIST_FILE = Runner/Info.plist;
 				INFOPLIST_KEY_CFBundleDisplayName = Noticeboard;
 				INFOPLIST_KEY_LSApplicationCategoryType = "public.app-category.education";
-				IPHONEOS_DEPLOYMENT_TARGET = 11.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",

noticeboard/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1430"
+   LastUpgradeVersion = "1510"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"

noticeboard/ios/Runner/Runner.entitlements

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict/>
+</plist>

noticeboard/lib/bloc/connectivity_status_bloc.dart

@@ -0,0 +1,49 @@
+import 'dart:async';
+import 'package:flutter/material.dart';
+import 'package:noticeboard/bloc/notice_detail_bloc.dart';
+import 'package:noticeboard/enum/connectivity_status_enum.dart';
+import 'package:noticeboard/enum/current_widget_enum.dart';
+
+class ConnectivityStatusBloc {
+  late BuildContext context;
+  late CurrentWidget currentWidget;
+  final _eventController = StreamController<ConnectivityStatus>.broadcast();
+  StreamSink<ConnectivityStatus> get eventSink => _eventController.sink;
+  Stream<ConnectivityStatus> get _eventStream => _eventController.stream;
+  ConnectivityStatus previousResult = ConnectivityStatus.connected;
+
+  static final ConnectivityStatusBloc _connectivityStatusBloc =
+      ConnectivityStatusBloc._();
+
+  final networkSnackBar =
+      const SnackBar(content: Text("Please check your internet connection!"));
+  final backOnlineSnackbar = const SnackBar(content: Text("Back online!"));
+
+  factory ConnectivityStatusBloc() => _connectivityStatusBloc;
+  final NoticeDetailBloc _noticeDetailBloc = NoticeDetailBloc();
+
+  ConnectivityStatusBloc._() {
+    _eventStream.listen((connectivityEvent) {
+      if (connectivityEvent == ConnectivityStatus.notConnected &&
+          previousResult == ConnectivityStatus.connected &&
+          context.mounted) {
+        ScaffoldMessenger.of(context).showSnackBar(networkSnackBar);
+      } else if (connectivityEvent == ConnectivityStatus.connected &&
+          previousResult == ConnectivityStatus.notConnected) {
+        ScaffoldMessenger.of(context).showSnackBar(backOnlineSnackbar);
+        if (currentWidget == CurrentWidget.noticeDetail) {
+          // Add an event in the sink so that notice detail webview can be refetched
+          _noticeDetailBloc.eventSink.add(CurrentWidget.noticeDetail);
+        } else {
+          // User is on list of notices , refetch them
+          _noticeDetailBloc.eventSink.add(CurrentWidget.listNotices);
+        }
+      }
+      previousResult = connectivityEvent;
+    });
+  }
+
+  void disposeStream() {
+    _eventController.close();
+  }
+}

noticeboard/lib/bloc/list_notices_bloc.dart

@@ -314,7 +314,6 @@ class ListNoticesBloc {
             DynamicFetch.fetchInstituteNotices)
           filterResult.endpoint =
               'api/noticeboard/institute_notices/?start=${filterResult.startDate}&end=${filterResult.endDate}';
-        // TODO: Add the if condition for Institute Notices case
       }
       PaginatedInfo paginatedInfo = await _listNoticesRepository
           .fetchFilteredNotices(filterResult.endpoint!, page);

noticeboard/lib/bloc/notice_detail_bloc.dart

@@ -0,0 +1,12 @@
+import 'dart:async';
+
+import 'package:noticeboard/enum/current_widget_enum.dart';
+
+class NoticeDetailBloc {
+  final _eventController = StreamController<CurrentWidget>.broadcast();
+  StreamSink<CurrentWidget> get eventSink => _eventController.sink;
+  Stream<CurrentWidget> get eventStream => _eventController.stream;
+  static final NoticeDetailBloc _noticeDetailBloc = NoticeDetailBloc._();
+  factory NoticeDetailBloc() => _noticeDetailBloc;
+  NoticeDetailBloc._();
+}

noticeboard/lib/enum/connectivity_status_enum.dart

@@ -0,0 +1,4 @@
+enum ConnectivityStatus{
+  connected , 
+  notConnected
+}

noticeboard/lib/enum/current_widget_enum.dart

@@ -0,0 +1,4 @@
+enum CurrentWidget {
+  listNotices,
+  noticeDetail
+}

noticeboard/lib/global/global_functions.dart

@@ -1,6 +1,11 @@
+import 'dart:async';
+import 'dart:io';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_form_builder/flutter_form_builder.dart';
 import 'package:form_builder_validators/form_builder_validators.dart';
+import 'package:noticeboard/bloc/connectivity_status_bloc.dart';
+import 'package:noticeboard/enum/connectivity_status_enum.dart';
 import 'package:noticeboard/global/global_constants.dart';
 import 'package:shimmer/shimmer.dart';
 import 'package:flutter_spinkit/flutter_spinkit.dart';
@@ -206,3 +211,26 @@ void showGenericError() {
     content: Text("Error!"),
   ));
 }
+
+Future<ConnectivityStatus> checkConnectivityStatus() async {
+  try {
+    final result = await InternetAddress.lookup("www.example.com");
+    if (result.isNotEmpty && result[0].rawAddress.isNotEmpty) {
+      return ConnectivityStatus.connected;
+    } else {
+      return ConnectivityStatus.notConnected;
+    }
+  } catch (e) {
+    return ConnectivityStatus.notConnected;
+  }
+}
+
+Timer addConnectivityStatusToSink() {
+  final ConnectivityStatusBloc _connectivityStatusBloc =
+      ConnectivityStatusBloc();
+  Timer _timer = Timer.periodic(Duration(seconds: 15), (timer) async {
+    ConnectivityStatus connectivityStatus = await checkConnectivityStatus();
+    _connectivityStatusBloc.eventSink.add(connectivityStatus);
+  });
+  return _timer;
+}

noticeboard/lib/main.dart

@@ -1,5 +1,6 @@
 import 'package:firebase_core/firebase_core.dart';
 import 'package:flutter/material.dart';
+import 'package:noticeboard/bloc/connectivity_status_bloc.dart';
 import './routes/routing_constants.dart';
 import './routes/routing.dart';
 import 'global/global_constants.dart';
@@ -19,6 +20,8 @@ class _MyAppState extends State<MyApp> {
   // This widget is the root of your application.
   @override
   void initState() {
+    ConnectivityStatusBloc _connectivityStatusBloc = ConnectivityStatusBloc();
+    _connectivityStatusBloc.context = context;
     super.initState();
   }
 

noticeboard/lib/routes/routing.dart

@@ -6,7 +6,6 @@ import './routing_constants.dart';
 import '../screens/login.dart';
 import '../screens/list_notices.dart';
 import '../screens/launching.dart';
-import '../models/notice_intro.dart';
 import '../screens/notice_detail.dart';
 
 class MyRouter {

noticeboard/lib/screens/bottom_navigation.dart

@@ -1,6 +1,8 @@
+import 'dart:async';
 import 'dart:io';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
+import 'package:noticeboard/global/global_functions.dart';
 import '../enum/dynamic_fetch_enum.dart';
 import '../screens/list_notices.dart';
 import '../models/notice_intro.dart';
@@ -14,6 +16,7 @@ class MyBottomNavigationBar extends StatefulWidget {
 
 class _MyBottomNavigationBarState extends State<MyBottomNavigationBar> {
   BottomNavigatorBloc _bottomNavigatorBloc = BottomNavigatorBloc();
+  late Timer _timer;
   final widgetOptions = [
     ListNotices(
       listNoticeMetaData: ListNoticeMetaData(
@@ -37,24 +40,33 @@ class _MyBottomNavigationBarState extends State<MyBottomNavigationBar> {
     _bottomNavigatorBloc.indexSink.add(index);
   }
 
+  @override
+  void initState() {
+    _timer = addConnectivityStatusToSink();
+    super.initState();
+  }
+
   @override
   void dispose() {
     _bottomNavigatorBloc.disposeStreams();
+    if (_timer.isActive) _timer.cancel();
     super.dispose();
   }
 
   @override
   Widget build(BuildContext context) {
-    return WillPopScope(
-      onWillPop: () async {
+    return PopScope(
+      canPop: false,
+      onPopInvoked: (didPop) async {
+        if (didPop) {
+          return;
+        }
         await Future.delayed(
           Duration(milliseconds: 500),
         );
         if (Platform.isAndroid) {
           SystemNavigator.pop();
-          return true;
         } else {
-          return false;
         }
       },
       child: StreamBuilder<int>(

noticeboard/lib/screens/filters.dart

@@ -55,7 +55,7 @@ class _FiltersState extends State<Filters> {
                 child: GestureDetector(
                   onTap: () {
                     _filtersBloc.eventSink.add(FilterEvents.resetGlobalSlug);
-                    WidgetsBinding.instance!.addPostFrameCallback((time) {
+                    WidgetsBinding.instance.addPostFrameCallback((time) {
                       onFilterClear();
                     });
                   },

noticeboard/lib/screens/launching.dart

@@ -12,7 +12,6 @@ import '../models/notice_intro.dart';
 import '../services/api_service/api_service.dart';
 import '../services/auth/auth_repository.dart';
 import '../global/global_functions.dart';
-import '../styles/launching_constants.dart';
 import '../styles/login_constants.dart';
 
 class Launcher extends StatefulWidget {