Add flutter_lints (#813)

add_to_app/prebuilt_module/flutter_module/analysis_options.yaml

@@ -0,0 +1,19 @@
+include: package:flutter_lints/flutter.yaml
+
+analyzer:
+  strong-mode:
+    implicit-casts: false
+    implicit-dynamic: false
+
+linter:
+  rules:
+    avoid_types_on_closure_parameters: true
+    avoid_void_async: true
+    cancel_subscriptions: true
+    close_sinks: true
+    directives_ordering: true
+    package_api_docs: true
+    package_prefixed_library_names: true
+    test_types_in_equals: true
+    throw_in_finally: true
+    unnecessary_statements: true

add_to_app/prebuilt_module/flutter_module/lib/main.dart

@@ -17,7 +17,7 @@ void main() {
   runApp(
     ChangeNotifierProvider.value(
       value: model,
-      child: MyApp(),
+      child: const MyApp(),
     ),
   );
 }
@@ -32,17 +32,17 @@ void main() {
 class CounterModel extends ChangeNotifier {
   CounterModel() {
     _channel.setMethodCallHandler(_handleMessage);
-    _channel.invokeMethod('requestCounter');
+    _channel.invokeMethod<void>('requestCounter');
   }
 
-  final _channel = MethodChannel('dev.flutter.example/counter');
+  final _channel = const MethodChannel('dev.flutter.example/counter');
 
   int _count = 0;
 
   int get count => _count;
 
   void increment() {
-    _channel.invokeMethod('incrementCounter');
+    _channel.invokeMethod<void>('incrementCounter');
   }
 
   Future<dynamic> _handleMessage(MethodCall call) async {
@@ -58,13 +58,15 @@ class CounterModel extends ChangeNotifier {
 /// It offers two routes, one suitable for displaying as a full screen and
 /// another designed to be part of a larger UI.class MyApp extends StatelessWidget {
 class MyApp extends StatelessWidget {
+  const MyApp({Key key}) : super(key: key);
+
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
       title: 'Flutter Module Title',
       routes: {
-        '/': (context) => FullScreenView(),
-        '/mini': (context) => Contents(),
+        '/': (context) => const FullScreenView(),
+        '/mini': (context) => const Contents(),
       },
     );
   }
@@ -73,11 +75,13 @@ class MyApp extends StatelessWidget {
 /// Wraps [Contents] in a Material [Scaffold] so it looks correct when displayed
 /// full-screen.
 class FullScreenView extends StatelessWidget {
+  const FullScreenView({Key key}) : super(key: key);
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
-        title: Text('Full-screen Flutter'),
+        title: const Text('Full-screen Flutter'),
       ),
       body: const Contents(showExit: true),
     );
@@ -92,7 +96,7 @@ class FullScreenView extends StatelessWidget {
 class Contents extends StatelessWidget {
   final bool showExit;
 
-  const Contents({this.showExit = false});
+  const Contents({this.showExit = false, Key key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -108,7 +112,7 @@ class Contents extends StatelessWidget {
               ),
             ),
           ),
-          Positioned.fill(
+          const Positioned.fill(
             child: Opacity(
               opacity: .25,
               child: FittedBox(
@@ -126,7 +130,7 @@ class Contents extends StatelessWidget {
                   '${mediaInfo.size.height.toStringAsFixed(1)}',
                   style: Theme.of(context).textTheme.headline5,
                 ),
-                SizedBox(height: 16),
+                const SizedBox(height: 16),
                 Consumer<CounterModel>(
                   builder: (context, model, child) {
                     return Text(
@@ -135,20 +139,20 @@ class Contents extends StatelessWidget {
                     );
                   },
                 ),
-                SizedBox(height: 16),
+                const SizedBox(height: 16),
                 Consumer<CounterModel>(
                   builder: (context, model, child) {
                     return ElevatedButton(
                       onPressed: () => model.increment(),
-                      child: Text('Tap me!'),
+                      child: const Text('Tap me!'),
                     );
                   },
                 ),
                 if (showExit) ...[
-                  SizedBox(height: 16),
+                  const SizedBox(height: 16),
                   ElevatedButton(
                     onPressed: () => SystemNavigator.pop(animated: true),
-                    child: Text('Exit this screen'),
+                    child: const Text('Exit this screen'),
                   ),
                 ],
               ],

add_to_app/prebuilt_module/flutter_module/pubspec.lock

@@ -88,6 +88,13 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_lints:
+    dependency: "direct dev"
+    description:
+      name: flutter_lints
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.3"
   flutter_test:
     dependency: "direct dev"
     description: flutter
@@ -98,6 +105,13 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  lints:
+    dependency: transitive
+    description:
+      name: lints
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.1"
   matcher:
     dependency: transitive
     description:

add_to_app/prebuilt_module/flutter_module/pubspec.yaml

@@ -17,6 +17,7 @@ dev_dependencies:
   flutter_driver:
     sdk: flutter
   espresso: ^0.0.1+2
+  flutter_lints: ^1.0.0
 
 flutter:
   uses-material-design: true

add_to_app/prebuilt_module/flutter_module/test/widget_test.dart

@@ -10,8 +10,10 @@ import 'package:provider/provider.dart';
 class MockCounterModel extends ChangeNotifier implements CounterModel {
   int _count = 0;
 
+  @override
   int get count => _count;
 
+  @override
   void increment() {
     _count++;
     notifyListeners();
@@ -19,13 +21,13 @@ class MockCounterModel extends ChangeNotifier implements CounterModel {
 }
 
 void main() {
-  testWidgets('MiniView smoke test', (WidgetTester tester) async {
+  testWidgets('MiniView smoke test', (tester) async {
     // Build our app and trigger a frame.
     await tester.pumpWidget(
       MaterialApp(
         home: ChangeNotifierProvider<CounterModel>.value(
           value: MockCounterModel(),
-          child: Contents(),
+          child: const Contents(),
         ),
       ),
     );