[shared_preferences] Migrate examples to NNBD (#3564)

Migrate all examples to NNBD so that the example apps will run in strong mode.

Converts macOS example to use the platform interface to remove circular dependencies (code is based on the Linux and Windows versions which already use essentially that approach).

Author: stuartmorgan-g

packages/shared_preferences/shared_preferences/example/integration_test/shared_preferences_test.dart

@@ -1,3 +1,9 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// @dart=2.9
+
 import 'dart:async';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:shared_preferences/shared_preferences.dart';

packages/shared_preferences/shared_preferences/example/lib/main.dart

@@ -24,15 +24,15 @@ class MyApp extends StatelessWidget {
 }
 
 class SharedPreferencesDemo extends StatefulWidget {
-  SharedPreferencesDemo({Key key}) : super(key: key);
+  SharedPreferencesDemo({Key? key}) : super(key: key);
 
   @override
   SharedPreferencesDemoState createState() => SharedPreferencesDemoState();
 }
 
 class SharedPreferencesDemoState extends State<SharedPreferencesDemo> {
   Future<SharedPreferences> _prefs = SharedPreferences.getInstance();
-  Future<int> _counter;
+  late Future<int> _counter;
 
   Future<void> _incrementCounter() async {
     final SharedPreferences prefs = await _prefs;

packages/shared_preferences/shared_preferences/example/pubspec.yaml

@@ -23,6 +23,5 @@ flutter:
   uses-material-design: true
 
 environment:
-  sdk: ">=2.0.0-dev.28.0 <3.0.0"
+  sdk: ">=2.12.0-0 <3.0.0"
   flutter: ">=1.9.1+hotfix.2"
-

packages/shared_preferences/shared_preferences/example/test_driver/integration_test.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart=2.9
+
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';

packages/shared_preferences/shared_preferences_linux/example/integration_test/shared_preferences_test.dart

@@ -1,3 +1,9 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// @dart=2.9
+
 import 'dart:async';
 
 import 'package:flutter_test/flutter_test.dart';

packages/shared_preferences/shared_preferences_linux/example/lib/main.dart

@@ -24,22 +24,22 @@ class MyApp extends StatelessWidget {
 }
 
 class SharedPreferencesDemo extends StatefulWidget {
-  SharedPreferencesDemo({Key key}) : super(key: key);
+  SharedPreferencesDemo({Key? key}) : super(key: key);
 
   @override
   SharedPreferencesDemoState createState() => SharedPreferencesDemoState();
 }
 
 class SharedPreferencesDemoState extends State<SharedPreferencesDemo> {
   final prefs = SharedPreferencesLinux.instance;
-  Future<int> _counter;
+  late Future<int> _counter;
 
   Future<void> _incrementCounter() async {
     final values = await prefs.getAll();
-    final int counter = (values['counter'] as int ?? 0) + 1;
+    final int counter = (values['counter'] as int? ?? 0) + 1;
 
     setState(() {
-      _counter = prefs.setValue(null, "counter", counter).then((bool success) {
+      _counter = prefs.setValue('Int', 'counter', counter).then((bool success) {
         return counter;
       });
     });
@@ -49,7 +49,7 @@ class SharedPreferencesDemoState extends State<SharedPreferencesDemo> {
   void initState() {
     super.initState();
     _counter = prefs.getAll().then((Map<String, Object> values) {
-      return (values['counter'] ?? 0);
+      return (values['counter'] as int? ?? 0);
     });
   }
 

packages/shared_preferences/shared_preferences_linux/example/pubspec.yaml

@@ -23,5 +23,5 @@ flutter:
   uses-material-design: true
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: ">=2.12.0-0 <3.0.0"
   flutter: ">=1.12.8"

packages/shared_preferences/shared_preferences_linux/example/test_driver/integration_test.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart=2.9
+
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';

packages/shared_preferences/shared_preferences_macos/example/integration_test/shared_preferences_test.dart

@@ -1,12 +1,18 @@
+// Copyright 2017, the Chromium project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// @dart=2.9
+
 import 'dart:async';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:shared_preferences/shared_preferences.dart';
+import 'package:shared_preferences_platform_interface/shared_preferences_platform_interface.dart';
 import 'package:integration_test/integration_test.dart';
 
 void main() {
   IntegrationTestWidgetsFlutterBinding.ensureInitialized();
 
-  group('$SharedPreferences', () {
+  group('SharedPreferencesMacOS', () {
     const Map<String, dynamic> kTestValues = <String, dynamic>{
       'flutter.String': 'hello world',
       'flutter.bool': true,
@@ -23,67 +29,81 @@ void main() {
       'flutter.List': <String>['baz', 'quox'],
     };
 
-    SharedPreferences preferences;
+    SharedPreferencesStorePlatform preferences;
 
     setUp(() async {
-      preferences = await SharedPreferences.getInstance();
+      preferences = SharedPreferencesStorePlatform.instance;
     });
 
     tearDown(() {
       preferences.clear();
     });
 
-    test('reading', () async {
-      expect(preferences.get('String'), isNull);
-      expect(preferences.get('bool'), isNull);
-      expect(preferences.get('int'), isNull);
-      expect(preferences.get('double'), isNull);
-      expect(preferences.get('List'), isNull);
-      expect(preferences.getString('String'), isNull);
-      expect(preferences.getBool('bool'), isNull);
-      expect(preferences.getInt('int'), isNull);
-      expect(preferences.getDouble('double'), isNull);
-      expect(preferences.getStringList('List'), isNull);
+    // Normally the app-facing package adds the prefix, but since this test
+    // bypasses the app-facing package it needs to be manually added.
+    String _prefixedKey(String key) {
+      return 'flutter.$key';
+    }
+
+    testWidgets('reading', (WidgetTester _) async {
+      final Map<String, Object> values = await preferences.getAll();
+      expect(values[_prefixedKey('String')], isNull);
+      expect(values[_prefixedKey('bool')], isNull);
+      expect(values[_prefixedKey('int')], isNull);
+      expect(values[_prefixedKey('double')], isNull);
+      expect(values[_prefixedKey('List')], isNull);
     });
 
-    test('writing', () async {
+    testWidgets('writing', (WidgetTester _) async {
       await Future.wait(<Future<bool>>[
-        preferences.setString('String', kTestValues2['flutter.String']),
-        preferences.setBool('bool', kTestValues2['flutter.bool']),
-        preferences.setInt('int', kTestValues2['flutter.int']),
-        preferences.setDouble('double', kTestValues2['flutter.double']),
-        preferences.setStringList('List', kTestValues2['flutter.List'])
+        preferences.setValue(
+            'String', _prefixedKey('String'), kTestValues2['flutter.String']),
+        preferences.setValue(
+            'Bool', _prefixedKey('bool'), kTestValues2['flutter.bool']),
+        preferences.setValue(
+            'Int', _prefixedKey('int'), kTestValues2['flutter.int']),
+        preferences.setValue(
+            'Double', _prefixedKey('double'), kTestValues2['flutter.double']),
+        preferences.setValue(
+            'StringList', _prefixedKey('List'), kTestValues2['flutter.List'])
       ]);
-      expect(preferences.getString('String'), kTestValues2['flutter.String']);
-      expect(preferences.getBool('bool'), kTestValues2['flutter.bool']);
-      expect(preferences.getInt('int'), kTestValues2['flutter.int']);
-      expect(preferences.getDouble('double'), kTestValues2['flutter.double']);
-      expect(preferences.getStringList('List'), kTestValues2['flutter.List']);
+      final Map<String, Object> values = await preferences.getAll();
+      expect(values[_prefixedKey('String')], kTestValues2['flutter.String']);
+      expect(values[_prefixedKey('bool')], kTestValues2['flutter.bool']);
+      expect(values[_prefixedKey('int')], kTestValues2['flutter.int']);
+      expect(values[_prefixedKey('double')], kTestValues2['flutter.double']);
+      expect(values[_prefixedKey('List')], kTestValues2['flutter.List']);
     });
 
-    test('removing', () async {
-      const String key = 'testKey';
-      await preferences.setString(key, kTestValues['flutter.String']);
-      await preferences.setBool(key, kTestValues['flutter.bool']);
-      await preferences.setInt(key, kTestValues['flutter.int']);
-      await preferences.setDouble(key, kTestValues['flutter.double']);
-      await preferences.setStringList(key, kTestValues['flutter.List']);
+    testWidgets('removing', (WidgetTester _) async {
+      final String key = _prefixedKey('testKey');
+      await preferences.setValue('String', key, kTestValues['flutter.String']);
+      await preferences.setValue('Bool', key, kTestValues['flutter.bool']);
+      await preferences.setValue('Int', key, kTestValues['flutter.int']);
+      await preferences.setValue('Double', key, kTestValues['flutter.double']);
+      await preferences.setValue(
+          'StringList', key, kTestValues['flutter.List']);
       await preferences.remove(key);
-      expect(preferences.get('testKey'), isNull);
+      final Map<String, Object> values = await preferences.getAll();
+      expect(values[key], isNull);
     });
 
-    test('clearing', () async {
-      await preferences.setString('String', kTestValues['flutter.String']);
-      await preferences.setBool('bool', kTestValues['flutter.bool']);
-      await preferences.setInt('int', kTestValues['flutter.int']);
-      await preferences.setDouble('double', kTestValues['flutter.double']);
-      await preferences.setStringList('List', kTestValues['flutter.List']);
+    testWidgets('clearing', (WidgetTester _) async {
+      await preferences.setValue(
+          'String', 'String', kTestValues['flutter.String']);
+      await preferences.setValue('Bool', 'bool', kTestValues['flutter.bool']);
+      await preferences.setValue('Int', 'int', kTestValues['flutter.int']);
+      await preferences.setValue(
+          'Double', 'double', kTestValues['flutter.double']);
+      await preferences.setValue(
+          'StringList', 'List', kTestValues['flutter.List']);
       await preferences.clear();
-      expect(preferences.getString('String'), null);
-      expect(preferences.getBool('bool'), null);
-      expect(preferences.getInt('int'), null);
-      expect(preferences.getDouble('double'), null);
-      expect(preferences.getStringList('List'), null);
+      final Map<String, Object> values = await preferences.getAll();
+      expect(values['String'], null);
+      expect(values['bool'], null);
+      expect(values['int'], null);
+      expect(values['double'], null);
+      expect(values['List'], null);
     });
   });
 }

packages/shared_preferences/shared_preferences_macos/example/lib/main.dart

@@ -7,7 +7,7 @@
 import 'dart:async';
 
 import 'package:flutter/material.dart';
-import 'package:shared_preferences/shared_preferences.dart';
+import 'package:shared_preferences_platform_interface/shared_preferences_platform_interface.dart';
 
 void main() {
   runApp(MyApp());
@@ -24,22 +24,28 @@ class MyApp extends StatelessWidget {
 }
 
 class SharedPreferencesDemo extends StatefulWidget {
-  SharedPreferencesDemo({Key key}) : super(key: key);
+  SharedPreferencesDemo({Key? key}) : super(key: key);
 
   @override
   SharedPreferencesDemoState createState() => SharedPreferencesDemoState();
 }
 
 class SharedPreferencesDemoState extends State<SharedPreferencesDemo> {
-  Future<SharedPreferences> _prefs = SharedPreferences.getInstance();
-  Future<int> _counter;
+  SharedPreferencesStorePlatform _prefs =
+      SharedPreferencesStorePlatform.instance;
+  late Future<int> _counter;
+
+  // Includes the prefix because this is using the platform interface directly,
+  // but the prefix (which the native code assumes is present) is added by the
+  // app-facing package.
+  static const String _prefKey = 'flutter.counter';
 
   Future<void> _incrementCounter() async {
-    final SharedPreferences prefs = await _prefs;
-    final int counter = (prefs.getInt('counter') ?? 0) + 1;
+    final Map<String, Object> values = await _prefs.getAll();
+    final int counter = ((values[_prefKey] as int?) ?? 0) + 1;
 
     setState(() {
-      _counter = prefs.setInt("counter", counter).then((bool success) {
+      _counter = _prefs.setValue('Int', _prefKey, counter).then((bool success) {
         return counter;
       });
     });
@@ -48,8 +54,8 @@ class SharedPreferencesDemoState extends State<SharedPreferencesDemo> {
   @override
   void initState() {
     super.initState();
-    _counter = _prefs.then((SharedPreferences prefs) {
-      return (prefs.getInt('counter') ?? 0);
+    _counter = _prefs.getAll().then((Map<String, Object> values) {
+      return (values[_prefKey] as int?) ?? 0;
     });
   }