Proxy provider (rrousselGit#59)

.travis.yml

@@ -12,10 +12,16 @@ before_script:
 script:
   # abort on error
   - set -e
+
   - flutter packages get
   - flutter format --set-exit-if-changed lib example test
   - flutter analyze --no-current-package lib test/ example/
   - flutter test --no-pub --coverage
+  - set +e # disable abort on error for the `cd`, otherwise the CI unexpectedly stops
+  - cd example/
+  - set -e
+  - flutter test --no-pub --coverage
+
   # export coverage
   - bash <(curl -s https://codecov.io/bash)
 cache:

CHANGELOG.md

@@ -10,6 +10,9 @@
 
 ## non-breaking:
 
+- Added `ProxyProvider`, `ListenableProxyProvider`, and `ChangeNotifierProxyProvider`.
+  These providers allows building values that depends on other providers,
+  without loosing reactivity or manually handling the state.
 - Added `DelegateWidget` and a few related classes to help building custom providers.
 - Exposed the internal generic `InheritedWidget` to help building custom providers.
 

example/.gitignore

@@ -0,0 +1,70 @@
+# Miscellaneous
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.buildlog/
+.history
+.svn/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# Visual Studio Code related
+.vscode/
+
+# Flutter/Dart/Pub related
+**/doc/api/
+.dart_tool/
+.flutter-plugins
+.packages
+.pub-cache/
+.pub/
+/build/
+
+# Android related
+**/android/**/gradle-wrapper.jar
+**/android/.gradle
+**/android/captures/
+**/android/gradlew
+**/android/gradlew.bat
+**/android/local.properties
+**/android/**/GeneratedPluginRegistrant.java
+
+# iOS/XCode related
+**/ios/**/*.mode1v3
+**/ios/**/*.mode2v3
+**/ios/**/*.moved-aside
+**/ios/**/*.pbxuser
+**/ios/**/*.perspectivev3
+**/ios/**/*sync/
+**/ios/**/.sconsign.dblite
+**/ios/**/.tags*
+**/ios/**/.vagrant/
+**/ios/**/DerivedData/
+**/ios/**/Icon?
+**/ios/**/Pods/
+**/ios/**/.symlinks/
+**/ios/**/profile
+**/ios/**/xcuserdata
+**/ios/.generated/
+**/ios/Flutter/App.framework
+**/ios/Flutter/Flutter.framework
+**/ios/Flutter/Generated.xcconfig
+**/ios/Flutter/app.flx
+**/ios/Flutter/app.zip
+**/ios/Flutter/flutter_assets/
+**/ios/ServiceDefinitions.json
+**/ios/Runner/GeneratedPluginRegistrant.*
+
+# Exceptions to above rules.
+!**/ios/**/default.mode1v3
+!**/ios/**/default.mode2v3
+!**/ios/**/default.pbxuser
+!**/ios/**/default.perspectivev3
+!/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages

example/.metadata

@@ -0,0 +1,10 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: b593f5167bce84fb3cad5c258477bf3abc1b14eb
+  channel: unknown
+
+project_type: app

example/lib/main.dart

@@ -0,0 +1,125 @@
+// ignore_for_file: public_member_api_docs
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+
+void main() => runApp(MyApp());
+
+class Counter with ChangeNotifier {
+  int _count = 0;
+  int get count => _count;
+
+  void increment() {
+    _count++;
+    notifyListeners();
+  }
+}
+
+class MyApp extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return MultiProvider(
+      providers: [
+        ChangeNotifierProvider(builder: (_) => Counter()),
+      ],
+      child: Consumer<Counter>(
+        builder: (context, counter, _) {
+          return MaterialApp(
+            supportedLocales: const [Locale('en')],
+            localizationsDelegates: [
+              DefaultMaterialLocalizations.delegate,
+              DefaultWidgetsLocalizations.delegate,
+              _ExampleLocalizationsDelegate(counter.count),
+            ],
+            home: const MyHomePage(),
+          );
+        },
+      ),
+    );
+  }
+}
+
+class ExampleLocalizations {
+  static ExampleLocalizations of(BuildContext context) =>
+      Localizations.of<ExampleLocalizations>(context, ExampleLocalizations);
+
+  const ExampleLocalizations(this._count);
+
+  final int _count;
+
+  String get title => 'Tapped $_count times';
+}
+
+class _ExampleLocalizationsDelegate
+    extends LocalizationsDelegate<ExampleLocalizations> {
+  const _ExampleLocalizationsDelegate(this.count);
+
+  final int count;
+
+  @override
+  bool isSupported(Locale locale) => locale.languageCode == 'en';
+
+  @override
+  Future<ExampleLocalizations> load(Locale locale) =>
+      SynchronousFuture(ExampleLocalizations(count));
+
+  @override
+  bool shouldReload(_ExampleLocalizationsDelegate old) => old.count != count;
+}
+
+class MyHomePage extends StatelessWidget {
+  const MyHomePage({Key key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: const Title()),
+      body: const Center(child: CounterLabel()),
+      floatingActionButton: const IncrementCounterButton(),
+    );
+  }
+}
+
+class IncrementCounterButton extends StatelessWidget {
+  const IncrementCounterButton({Key key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return FloatingActionButton(
+      onPressed: Provider.of<Counter>(context).increment,
+      tooltip: 'Increment',
+      child: const Icon(Icons.add),
+    );
+  }
+}
+
+class CounterLabel extends StatelessWidget {
+  const CounterLabel({Key key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    final counter = Provider.of<Counter>(context);
+    return Column(
+      mainAxisSize: MainAxisSize.min,
+      mainAxisAlignment: MainAxisAlignment.center,
+      children: <Widget>[
+        const Text(
+          'You have pushed the button this many times:',
+        ),
+        Text(
+          '${counter.count}',
+          style: Theme.of(context).textTheme.display1,
+        ),
+      ],
+    );
+  }
+}
+
+class Title extends StatelessWidget {
+  const Title({Key key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Text(ExampleLocalizations.of(context).title);
+  }
+}

example/pubspec.yaml

@@ -1,15 +1,15 @@
 name: example
 version: 1.0.0
-homepage: https://github.com/rrousselGit/provider
+homepage: https://github.com/rrousselGit/provider	
 author: Remi Rousselet <[email protected]>
 
 environment:
-  sdk: ">=2.0.0 <3.0.0"
+  sdk: ">=2.1.0 <3.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
-  provider: 1.1.1
+  provider:
 
 dev_dependencies:
   flutter_test:
@@ -18,3 +18,6 @@ dev_dependencies:
 dependency_overrides:
   provider:
     path: ../
+
+flutter:
+  uses-material-design: true

example/test/widget_test.dart

@@ -0,0 +1,35 @@
+// This is a basic Flutter widget test.
+//
+// To perform an interaction with a widget in your test, use the WidgetTester
+// utility that Flutter provides. For example, you can send tap and scroll
+// gestures. You can also use WidgetTester to find child widgets in the widget
+// tree, read text, and verify that the values of widget properties are correct.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:example/main.dart' as example;
+
+void main() {
+  testWidgets('Counter increments smoke test', (WidgetTester tester) async {
+    // Build our app and trigger a frame.
+
+    example.main();
+
+    // Verify that our counter starts at 0.
+    expect(find.text('0'), findsOneWidget);
+    expect(find.text('1'), findsNothing);
+    expect(find.text('Tapped 0 times'), findsOneWidget);
+    expect(find.text('Tapped 1 times'), findsNothing);
+
+    // Tap the '+' icon and trigger a frame.
+    await tester.tap(find.byIcon(Icons.add));
+    await tester.pump();
+
+    // Verify that our counter has incremented.
+    expect(find.text('0'), findsNothing);
+    expect(find.text('1'), findsOneWidget);
+    expect(find.text('Tapped 0 times'), findsNothing);
+    expect(find.text('Tapped 1 times'), findsOneWidget);
+  });
+}

lib/provider.dart

@@ -1,7 +1,10 @@
 library provider;
 
 export 'src/async_provider.dart';
+export 'src/change_notifier_provider.dart';
 export 'src/consumer.dart';
 export 'src/delegate_widget.dart';
 export 'src/listenable_provider.dart';
 export 'src/provider.dart';
+export 'src/proxy_provider.dart' hide NumericProxyProvider, Void;
+export 'src/value_listenable_provider.dart';