persistance

lib/main.dart

@@ -1,19 +1,33 @@
 import 'package:flutter/material.dart';
 
 import 'package:provider/provider.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+import 'package:we_find/model/model.dart';
 import 'package:we_find/providers/fav_course_provider.dart';
 import 'package:we_find/providers/lang_provider.dart';
 import 'package:we_find/screens/home_screen.dart';
 import 'package:we_find/styles/theme.dart' as Theme;
 
-void main() => runApp(appProvider(WeFindApp()));
+void main() async =>
+    runApp(appProvider(WeFindApp(), await _getSavedFavorites()));
+
+Future<Set<CourseID>> _getSavedFavorites() async {
+  // obtain shared preferences
+  final prefs = await SharedPreferences.getInstance();
+
+  String? favscsv = prefs.getString("favorites");
+
+  if (favscsv == null) return {};
+
+  return favscsv.split(',').map((e) => CourseID(e)).toSet();
+}
 
 /// Wraps the supplied [appRoot] into a [MultiProvider] that gives access to
 /// all the shared states for the Widget-tree.
-MultiProvider appProvider(Widget appRoot) => MultiProvider(
+MultiProvider appProvider(Widget appRoot, Set<CourseID> favs) => MultiProvider(
       providers: [
         ChangeNotifierProvider<FavCourseProvider>(
-          create: (_) => FavCourseProvider(),
+          create: (_) => FavCourseProvider(favs),
         ),
         ChangeNotifierProvider<LangProvider>(
           create: (_) => LangProvider(),
@@ -23,13 +37,34 @@ MultiProvider appProvider(Widget appRoot) => MultiProvider(
     );
 
 class WeFindApp extends StatelessWidget {
+  FavCourseProvider? _favCourses;
+
   @override
   Widget build(BuildContext context) {
+    _favCourses = Provider.of<FavCourseProvider>(context);
     return MaterialApp(
       title: 'we:find',
       theme: Theme.lightThemeData,
       home: HomeScreen(),
       debugShowCheckedModeBanner: false,
     );
   }
+
+  @override
+  void detached() async {
+    if (_favCourses == null) return;
+
+    String ret = "";
+    bool first = true;
+    for (CourseID eachCourseID in _favCourses!.courses) {
+      if (!first) {
+        ret += ",";
+      }
+      ret += eachCourseID.id!;
+      first = false;
+    }
+
+    final prefs = await SharedPreferences.getInstance();
+    print(await prefs.setString("favorites", ret));
+  }
 }

lib/providers/fav_course_provider.dart

@@ -1,11 +1,13 @@
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:we_find/model/model.dart';
-import 'package:we_find/model/model_wrapped.dart';
 
 /// Provider that keeps track of the [Course] instances
 /// that were marked as favourite by the user
 class FavCourseProvider with ChangeNotifier {
-  final Set<CourseID> _courses = {};
+  final Set<CourseID> _courses;
+
+  FavCourseProvider(this._courses);
 
   Set<CourseID> get courses => _courses;
 

pubspec.lock

@@ -127,6 +127,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.2.0"
+  ffi:
+    dependency: transitive
+    description:
+      name: ffi
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.0"
   file:
     dependency: transitive
     description:
@@ -296,6 +303,27 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.2.1"
+  path_provider_linux:
+    dependency: transitive
+    description:
+      name: path_provider_linux
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
+  path_provider_platform_interface:
+    dependency: transitive
+    description:
+      name: path_provider_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.1"
+  path_provider_windows:
+    dependency: transitive
+    description:
+      name: path_provider_windows
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.1"
   pedantic:
     dependency: transitive
     description:
@@ -310,13 +338,34 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "4.1.0"
+  platform:
+    dependency: transitive
+    description:
+      name: platform
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.0"
+  plugin_platform_interface:
+    dependency: transitive
+    description:
+      name: plugin_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
   pool:
     dependency: transitive
     description:
       name: pool
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.5.0"
+  process:
+    dependency: transitive
+    description:
+      name: process
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "4.2.1"
   provider:
     dependency: "direct main"
     description:
@@ -338,6 +387,48 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "3.0.1"
+  shared_preferences:
+    dependency: "direct main"
+    description:
+      name: shared_preferences
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.5"
+  shared_preferences_linux:
+    dependency: transitive
+    description:
+      name: shared_preferences_linux
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
+  shared_preferences_macos:
+    dependency: transitive
+    description:
+      name: shared_preferences_macos
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
+  shared_preferences_platform_interface:
+    dependency: transitive
+    description:
+      name: shared_preferences_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
+  shared_preferences_web:
+    dependency: transitive
+    description:
+      name: shared_preferences_web
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
+  shared_preferences_windows:
+    dependency: transitive
+    description:
+      name: shared_preferences_windows
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
   shelf:
     dependency: transitive
     description:
@@ -546,6 +637,20 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.4"
+  win32:
+    dependency: transitive
+    description:
+      name: win32
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.5"
+  xdg_directories:
+    dependency: transitive
+    description:
+      name: xdg_directories
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.2.0"
   xml:
     dependency: "direct main"
     description:

pubspec.yaml

@@ -32,6 +32,7 @@ dependencies:
   provider: ^5.0.0
   xml: ^5.1.0
   flutter_html: ^2.0.0
+  shared_preferences: ^2.0.5
 
 
 dev_dependencies: