Add lifecycle observer

coffee_maker_navigator_2/android/app/src/main/AndroidManifest.xml

@@ -2,6 +2,7 @@
     <application
         android:label="coffee_maker_navigator_2"
         android:name="${applicationName}"
+        android:enableOnBackInvokedCallback="true"
         android:icon="@mipmap/ic_launcher">
         <activity
             android:name=".MainActivity"

coffee_maker_navigator_2/lib/app/app.dart

@@ -1,3 +1,4 @@
+import 'package:coffee_maker_navigator_2/app/app_lifecycle/ui/app_lifecycle_listenable.dart';
 import 'package:wolt_di/wolt_di.dart';
 import 'package:coffee_maker_navigator_2/app/di/coffee_maker_app_level_dependency_container.dart';
 import 'package:demo_ui_components/demo_ui_components.dart';
@@ -13,12 +14,14 @@ class CoffeeMakerApp extends StatelessWidget {
         final appLevelDependencyContainer = DependencyInjector.container<
             CoffeeMakerAppLevelDependencyContainer>(context);
 
-        return MaterialApp.router(
-          debugShowCheckedModeBanner: false,
-          theme: AppThemeData.themeData(context),
-          routerDelegate: appLevelDependencyContainer.appRouterDelegate,
-          backButtonDispatcher:
-              appLevelDependencyContainer.backButtonDispatcher,
+        return AppLifecycleObserver(
+          child: MaterialApp.router(
+            debugShowCheckedModeBanner: false,
+            theme: AppThemeData.themeData(context),
+            routerDelegate: appLevelDependencyContainer.appRouterDelegate,
+            backButtonDispatcher:
+                appLevelDependencyContainer.backButtonDispatcher,
+          ),
         );
       }),
     );

coffee_maker_navigator_2/lib/app/app_lifecycle/domain/app_lifecyle_service.dart

@@ -0,0 +1,25 @@
+import 'package:flutter/foundation.dart';
+
+enum AppLifeCycleState {
+  foreground,
+  background,
+}
+
+class AppLifeCycleService {
+  late ValueNotifier<AppLifeCycleState> lifeCycleState;
+
+  ValueListenable<AppLifeCycleState> get appLifeStateListenable =>
+      lifeCycleState;
+
+  AppLifeCycleService() {
+    lifeCycleState = ValueNotifier(AppLifeCycleState.foreground);
+  }
+
+  void onForegrounded() {
+    lifeCycleState.value = AppLifeCycleState.foreground;
+  }
+
+  void onBackgrounded() {
+    lifeCycleState.value = AppLifeCycleState.background;
+  }
+}

coffee_maker_navigator_2/lib/app/app_lifecycle/ui/app_lifecycle_listenable.dart

@@ -0,0 +1,46 @@
+import 'package:coffee_maker_navigator_2/app/di/coffee_maker_app_level_dependency_container.dart';
+import 'package:flutter/widgets.dart';
+import 'package:wolt_di/wolt_di.dart';
+
+class AppLifecycleObserver extends StatefulWidget {
+  const AppLifecycleObserver({required this.child, super.key});
+
+  final Widget child;
+
+  @override
+  State<AppLifecycleObserver> createState() => _AppLifecycleObserverState();
+}
+
+class _AppLifecycleObserverState extends State<AppLifecycleObserver> {
+  late final AppLifecycleListener listener;
+
+  @override
+  void initState() {
+    super.initState();
+    final appLevelDependencyContainer =
+        DependencyInjector.container<CoffeeMakerAppLevelDependencyContainer>(
+            context);
+    final appLifeCycleService = appLevelDependencyContainer.appLifeCycleService;
+    listener = AppLifecycleListener(
+      onShow: () {
+        debugPrint('AppLifecycleListener: onForegrounded');
+        appLifeCycleService.onForegrounded();
+      },
+      onHide: () {
+        debugPrint('AppLifecycleListener: onBackgrounded');
+        appLifeCycleService.onBackgrounded();
+      },
+    );
+  }
+
+  @override
+  void dispose() {
+    listener.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return widget.child;
+  }
+}

coffee_maker_navigator_2/lib/app/di/coffee_maker_app_level_dependency_container.dart

@@ -1,3 +1,4 @@
+import 'package:coffee_maker_navigator_2/app/app_lifecycle/domain/app_lifecyle_service.dart';
 import 'package:coffee_maker_navigator_2/app/auth/data/local/auth_local_data_source.dart';
 import 'package:coffee_maker_navigator_2/app/auth/data/repository/auth_repository.dart';
 import 'package:coffee_maker_navigator_2/app/auth/domain/auth_service.dart';
@@ -24,6 +25,8 @@ class CoffeeMakerAppLevelDependencyContainer
   late final _onboardingRepository = _createOnboardingRepository();
   late final _onboardingService = _createOnboardingService();
 
+  late final _appLifeCycleService = _createAppLifeCycleService();
+
   late final _appRouterDelegate = _createAppRouterDelegate();
   late final _backButtonDispatcher = _createRootBackButtonDispatcher();
   late final _routerViewModel = _createRouterViewModel();
@@ -32,6 +35,7 @@ class CoffeeMakerAppLevelDependencyContainer
   BackButtonDispatcher get backButtonDispatcher => _backButtonDispatcher;
   RouterViewModel get routerViewModel => _routerViewModel;
   AuthService get authService => _authService;
+  AppLifeCycleService get appLifeCycleService => _appLifeCycleService;
 
   CoffeeMakerAppLevelDependencyContainer();
 
@@ -78,4 +82,8 @@ class CoffeeMakerAppLevelDependencyContainer
       onboardingService: _onboardingService,
     );
   }
+
+  AppLifeCycleService _createAppLifeCycleService() {
+    return AppLifeCycleService();
+  }
 }

coffee_maker_navigator_2/lib/features/add_water/di/add_water_dependency_container.dart

@@ -4,8 +4,7 @@ import 'package:coffee_maker_navigator_2/features/add_water/domain/add_water_ser
 import 'package:coffee_maker_navigator_2/features/orders/domain/orders_service.dart';
 import 'package:coffee_maker_navigator_2/features/add_water/ui/view_model/add_water_view_model.dart';
 
-class AddWaterDependencyContainer
-    extends FeatureWithViewModelDependencyContainer {
+class AddWaterDependencyContainer extends FeatureLevelDependencyContainer {
   // Just in the sake to show that we can use a method here to make the service lazily initialized.
   late final AddWaterService _addWaterService = _createAddWaterService();
   // This is an example to non-lazy initialization.
@@ -20,7 +19,6 @@ class AddWaterDependencyContainer
     return AddWaterService();
   }
 
-  @override
   AddWaterViewModel createViewModel() => AddWaterViewModel(
         addWaterService: _addWaterService,
         ordersService: _ordersService,