Make KeyValueStore NNBD + add tryGet methods.

app/lib/blocs/sharezone_bloc_providers.dart

@@ -24,6 +24,7 @@ import 'package:flutter/material.dart';
 import 'package:hausaufgabenheft_logik/hausaufgabenheft_logik_lehrer.dart';
 import 'package:hausaufgabenheft_logik/hausaufgabenheft_logik_setup.dart';
 import 'package:http/http.dart' as http;
+import 'package:key_value_store/in_memory_key_value_store.dart';
 import 'package:sharezone/account/account_page_bloc_factory.dart';
 import 'package:sharezone/account/features/feature_gateway.dart';
 import 'package:sharezone/account/features/features_bloc.dart';

app/lib/util/cache/key_value_store.dart

@@ -6,6 +6,7 @@
 //
 // SPDX-License-Identifier: EUPL-1.2
 
+// @dart=2.14
 import 'dart:async';
 
 import 'package:key_value_store/key_value_store.dart';
@@ -34,24 +35,24 @@ class FlutterKeyValueStore extends KeyValueStore {
   Future<bool> clear() => preferences.clear();
 
   @override
-  bool getBool(String key) => preferences.getBool(key);
+  bool? getBool(String key) => preferences.getBool(key);
 
   @override
-  double getDouble(String key) => preferences.getDouble(key);
+  double? getDouble(String key) => preferences.getDouble(key);
 
   /// Reads a value from persistent storage, throwing an exception if it's not an int.
   @override
-  int getInt(String key) => preferences.getInt(key);
+  int? getInt(String key) => preferences.getInt(key);
 
   /// Returns all keys in the persistent storage.
   @override
   Set<String> getKeys() => preferences.getKeys();
 
   @override
-  String getString(String key) => preferences.getString(key);
+  String? getString(String key) => preferences.getString(key);
 
   @override
-  List<String> getStringList(String key) => preferences.getStringList(key);
+  List<String>? getStringList(String key) => preferences.getStringList(key);
 
   @override
   Future<bool> remove(String key) => preferences.remove(key);
@@ -81,85 +82,3 @@ class FlutterKeyValueStore extends KeyValueStore {
   @override
   bool containsKey(String key) => preferences.containsKey(key);
 }
-
-class InMemoryKeyValueStore extends KeyValueStore {
-  Map<String, dynamic> storedValues;
-
-  InMemoryKeyValueStore([this.storedValues]) {
-    storedValues ??= {};
-  }
-
-  @override
-  Future<bool> clear() {
-    storedValues.clear();
-    return null;
-  }
-
-  @override
-  bool getBool(String key) {
-    return storedValues[key] as bool;
-  }
-
-  @override
-  double getDouble(String key) {
-    return storedValues[key] as double;
-  }
-
-  @override
-  int getInt(String key) {
-    return storedValues[key] as int;
-  }
-
-  @override
-  Set<String> getKeys() {
-    return storedValues.keys.toSet();
-  }
-
-  @override
-  String getString(String key) {
-    return storedValues[key] as String;
-  }
-
-  @override
-  List<String> getStringList(String key) {
-    return storedValues[key] as List<String>;
-  }
-
-  @override
-  Future<bool> remove(String key) {
-    return Future.value(storedValues.remove(key) != null);
-  }
-
-  @override
-  Future<bool> setBool(String key, bool value) {
-    storedValues[key] = value;
-    return Future.value(true);
-  }
-
-  @override
-  Future<bool> setDouble(String key, double value) {
-    storedValues[key] = value;
-    return Future.value(true);
-  }
-
-  @override
-  Future<bool> setInt(String key, int value) {
-    storedValues[key] = value;
-    return Future.value(true);
-  }
-
-  @override
-  Future<bool> setString(String key, String value) {
-    storedValues[key] = value;
-    return Future.value(true);
-  }
-
-  @override
-  Future<bool> setStringList(String key, List<String> values) {
-    storedValues[key] = values;
-    return Future.value(true);
-  }
-
-  @override
-  bool containsKey(String key) => storedValues.containsKey(key);
-}

app/test/bottom_navigation_bar/bnb_tutorial_bloc_test.dart

@@ -6,10 +6,10 @@
 //
 // SPDX-License-Identifier: EUPL-1.2
 
+import 'package:key_value_store/in_memory_key_value_store.dart';
 import 'package:rxdart/subjects.dart';
 import 'package:sharezone/navigation/scaffold/portable/bottom_navigation_bar/tutorial/bnb_tutorial_bloc.dart';
 import 'package:sharezone/navigation/scaffold/portable/bottom_navigation_bar/tutorial/bnb_tutorial_cache.dart';
-import 'package:sharezone/util/cache/key_value_store.dart';
 import 'package:test/test.dart';
 
 import 'mock_bnb_tutorial_analytics.dart';

app/test/feedback/feedback_bloc_test.dart

@@ -7,14 +7,14 @@
 // SPDX-License-Identifier: EUPL-1.2
 
 import 'package:flutter_test/flutter_test.dart';
+import 'package:key_value_store/in_memory_key_value_store.dart';
 import 'package:key_value_store/key_value_store.dart';
 import 'package:random_string/random_string.dart' as random;
 import 'package:sharezone/feedback/src/analytics/feedback_analytics.dart';
 import 'package:sharezone/feedback/src/bloc/feedback_bloc.dart';
 import 'package:sharezone/feedback/src/cache/cooldown_exception.dart';
 import 'package:sharezone/feedback/src/cache/feedback_cache.dart';
 import 'package:sharezone/feedback/src/models/user_feedback.dart';
-import 'package:sharezone/util/cache/key_value_store.dart';
 
 import 'mock_feedback_api.dart';
 import 'mock_platform_information_retreiver.dart';

app/test/feedback/feedback_cache_test.dart

@@ -6,8 +6,8 @@
 //
 // SPDX-License-Identifier: EUPL-1.2
 
+import 'package:key_value_store/in_memory_key_value_store.dart';
 import 'package:sharezone/feedback/src/cache/feedback_cache.dart';
-import 'package:sharezone/util/cache/key_value_store.dart';
 import 'package:test/test.dart';
 
 void main() {
@@ -55,4 +55,4 @@ void main() {
       expect(onCooldown, true);
     });
   });
-}
+}

app/test/feedback/feedback_page_test.dart

@@ -9,13 +9,13 @@
 import 'package:bloc_provider/bloc_provider.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:key_value_store/in_memory_key_value_store.dart';
 import 'package:random_string/random_string.dart' as random;
 import 'package:sharezone/feedback/feedback_box_page.dart';
 import 'package:sharezone/feedback/src/bloc/feedback_bloc.dart';
 import 'package:sharezone/feedback/src/cache/cooldown_exception.dart';
 import 'package:sharezone/feedback/src/cache/feedback_cache.dart';
 import 'package:sharezone/feedback/src/models/user_feedback.dart';
-import 'package:sharezone/util/cache/key_value_store.dart';
 
 import 'feedback_bloc_test.dart';
 import 'mock_feedback_api.dart';

app/test/holidays/holiday_cache_test.dart

@@ -7,8 +7,8 @@
 // SPDX-License-Identifier: EUPL-1.2
 
 import 'package:built_collection/built_collection.dart';
+import 'package:key_value_store/in_memory_key_value_store.dart';
 import 'package:sharezone/models/extern_apis/holiday.dart';
-import 'package:sharezone/util/cache/key_value_store.dart';
 import 'package:sharezone/util/holidays/holiday_cache.dart';
 import 'package:sharezone/util/holidays/state.dart';
 import "package:test/test.dart";

app/test/holidays/integration_test.dart

@@ -8,10 +8,10 @@
 
 import 'package:async/async.dart';
 import 'package:http/http.dart' as http;
+import 'package:key_value_store/in_memory_key_value_store.dart';
 import 'package:mockito/mockito.dart';
 import 'package:sharezone/blocs/dashbord_widgets_blocs/holiday_bloc.dart';
 import 'package:sharezone/models/extern_apis/holiday.dart';
-import 'package:sharezone/util/cache/key_value_store.dart';
 import 'package:sharezone/util/holidays/api_cache_manager.dart';
 import 'package:sharezone/util/holidays/holiday_api.dart';
 import 'package:sharezone/util/holidays/holiday_cache.dart';

lib/key_value_store/lib/in_memory_key_value_store.dart

@@ -10,10 +10,10 @@ import 'dart:async';
 import 'package:key_value_store/key_value_store.dart';
 
 class InMemoryKeyValueStore extends KeyValueStore {
-  Map<String, dynamic> storedValues;
+  late Map<String, dynamic> storedValues;
 
-  InMemoryKeyValueStore([this.storedValues]) {
-    storedValues ??= {};
+  InMemoryKeyValueStore([Map<String, dynamic>? storedValues]) {
+    this.storedValues = storedValues ?? {};
   }
 
   @override

lib/key_value_store/lib/key_value_store.dart

@@ -11,41 +11,51 @@ abstract class KeyValueStore {
   Set<String> getKeys();
 
   /// Reads a value from persistent storage, throwing an exception if it's not a bool.
-  bool getBool(String key);
-  // Reads a value from persistent storage, throwing an exception if it's not an int.
-  int getInt(String key);
-  // Reads a value from persistent storage, throwing an exception if it's not a double.
-  double getDouble(String key);
-  // Reads a value from persistent storage, throwing an exception if it's not an String.
-  String getString(String key);
+  bool? getBool(String key);
+
+  /// Reads a value from persistent storage, returning null if it's not a bool.
+  bool? tryGetBool(String key) => _guard(() => getBool(key));
+
+  /// Reads a value from persistent storage, throwing an exception if it's not an int.
+  int? getInt(String key);
+
+  /// Reads a value from persistent storage, returning null if it's not an int.
+  int? tryGetInt(String key) => _guard(() => getInt(key));
+
+  /// Reads a value from persistent storage, throwing an exception if it's not a double.
+  double? getDouble(String key);
+
+  /// Reads a value from persistent storage, returning null if it's not a double.
+  double? tryGetDouble(String key) => _guard(() => getDouble(key));
+
+  /// Reads a value from persistent storage, throwing an exception if it's not an String.
+  String? getString(String key);
+
+  /// Reads a value from persistent storage, returning null if it's not an String.
+  String? tryGetString(String key) => _guard(() => getString(key));
 
   /// Reads a set of string values from persistent storage, throwing an exception if it's not a string set.
-  List<String> getStringList(String key);
+  List<String>? getStringList(String key);
+
+  /// Reads a set of string values from persistent storage, returning null if it's not a string set.
+  List<String>? tryGetStringList(String key) =>
+      _guard(() => getStringList(key));
 
   /// Saves a boolean [value] to persistent storage in the background.
-  ///
-  /// If [value] is null, this is equivalent to calling [remove()] on the [key].
   Future<bool> setBool(String key, bool value);
 
-  /// Reads a value from persistent storage, throwing an exception if it's not
-  /// an int.
+  /// Saves an int [value] to persistent storage in the background.
   Future<bool> setInt(String key, int value);
 
   /// Saves a double [value] to persistent storage in the background.
   ///
   /// Android doesn't support storing doubles, so it will be stored as a float.
-  ///
-  /// If [value] is null, this is equivalent to calling [remove()] on the [key].
   Future<bool> setDouble(String key, double value);
 
   /// Saves a string [value] to persistent storage in the background.
-  ///
-  /// If [value] is null, this is equivalent to calling [remove()] on the [key].
   Future<bool> setString(String key, String value);
 
   /// Saves a list of strings [value] to persistent storage in the background.
-  ///
-  /// If [value] is null, this is equivalent to calling [remove()] on the [key].
   Future<bool> setStringList(String key, List<String> values);
 
   /// Removes an entry from persistent storage.
@@ -56,4 +66,12 @@ abstract class KeyValueStore {
 
   /// Completes with true once the user preferences for the app has been cleared
   Future<bool> clear();
-}
+}
+
+T? _guard<T>(T? Function() f) {
+  try {
+    return f();
+  } catch (_) {
+    return null;
+  }
+}