Centralize analysis options (#957)

add_to_app/android_view/flutter_module_using_plugin/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../../analysis_options.yaml

add_to_app/books/flutter_module_books/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../../analysis_options.yaml

add_to_app/fullscreen/flutter_module/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../../analysis_options.yaml

add_to_app/multiple_flutters/multiple_flutters_module/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../../analysis_options.yaml

add_to_app/plugin/flutter_module_using_plugin/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../../analysis_options.yaml

add_to_app/prebuilt_module/flutter_module/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../../analysis_options.yaml

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

android_splash_screen/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

animations/analysis_options.yaml

@@ -1,21 +1,6 @@
-include: package:flutter_lints/flutter.yaml
-
-analyzer:
-  strong-mode:
-    implicit-casts: false
-    implicit-dynamic: false
+include: ../analysis_options.yaml
 
 linter:
   rules:
-    avoid_types_on_closure_parameters: true
-    avoid_void_async: true
-    cancel_subscriptions: true
-    close_sinks: true
-    directives_ordering: true
     # Required because of the numbered sources in  lib/src/basics
     file_names: false
-    package_api_docs: true
-    package_prefixed_library_names: true
-    test_types_in_equals: true
-    throw_in_finally: true
-    unnecessary_statements: true

experimental/desktop_photo_search/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../analysis_options.yaml

experimental/federated_plugin/federated_plugin/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../../analysis_options.yaml

experimental/federated_plugin/federated_plugin_macos/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../../analysis_options.yaml

experimental/federated_plugin/federated_plugin_platform_interface/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../../analysis_options.yaml

experimental/federated_plugin/federated_plugin_web/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../../analysis_options.yaml

experimental/federated_plugin/federated_plugin_windows/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../../analysis_options.yaml

experimental/linting_tool/analysis_options.yaml

@@ -1,22 +1,6 @@
-include: package:flutter_lints/flutter.yaml
+include: ../../analysis_options.yaml
 
 analyzer:
   exclude:
     - lib/model/rule.g.dart
     - test/widget_test.mocks.dart
-  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

experimental/web_dashboard/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../analysis_options.yaml

flutter_maps_firestore/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

form_app/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

infinite_list/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

ios_app_clip/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

isolate_example/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

jsonexample/analysis_options.yaml

@@ -1,22 +1,6 @@
-include: package:flutter_lints/flutter.yaml
+include: ../analysis_options.yaml
 
 analyzer:
   exclude:
     - lib/json_serializable/*.g.dart
     - lib/built_value/*.g.dart
-  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

navigation_and_routing/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

null_safety/null_safe_app/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../analysis_options.yaml

null_safety/null_unsafe_app/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../../analysis_options.yaml

place_tracker/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

platform_channels/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

platform_design/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

platform_view_swift/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

provider_counter/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

provider_shopper/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

testing_app/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

veggieseasons/analysis_options.yaml

@@ -1,19 +1 @@
-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
+include: ../analysis_options.yaml

web/particle_background/analysis_options.yaml

@@ -0,0 +1,11 @@
+include: ../../analysis_options.yaml
+
+analyzer:
+  strong-mode:
+    implicit-casts: true
+    implicit-dynamic: true
+
+linter:
+  rules:
+    constant_identifier_names: false
+

web/particle_background/lib/main.dart

@@ -3,12 +3,14 @@ import 'dart:math';
 import 'package:flutter/material.dart';
 import 'package:particle_background/simple_animations_package.dart';
 
-void main() => runApp(ParticleApp());
+void main() => runApp(const ParticleApp());
 
 class ParticleApp extends StatelessWidget {
+  const ParticleApp({Key? key}) : super(key: key);
+
   @override
   Widget build(BuildContext context) {
-    return MaterialApp(
+    return const MaterialApp(
       home: Scaffold(
         body: ParticleBackgroundPage(),
       ),
@@ -17,10 +19,12 @@ class ParticleApp extends StatelessWidget {
 }
 
 class ParticleBackgroundPage extends StatelessWidget {
+  const ParticleBackgroundPage({Key? key}) : super(key: key);
+
   @override
   Widget build(BuildContext context) {
     return Stack(
-      children: [
+      children: const [
         Positioned.fill(child: AnimatedBackground()),
         Positioned.fill(child: Particles(30)),
         Positioned.fill(child: CenteredText()),
@@ -32,7 +36,7 @@ class ParticleBackgroundPage extends StatelessWidget {
 class Particles extends StatefulWidget {
   final int numberOfParticles;
 
-  Particles(this.numberOfParticles);
+  const Particles(this.numberOfParticles, {key}) : super(key: key);
 
   @override
   _ParticlesState createState() => _ParticlesState();
@@ -54,7 +58,7 @@ class _ParticlesState extends State<Particles> {
   @override
   Widget build(BuildContext context) {
     return Rendering(
-      startTime: Duration(seconds: 30),
+      startTime: const Duration(seconds: 30),
       onTick: _simulateParticles,
       builder: (context, time) {
         return CustomPaint(
@@ -65,14 +69,16 @@ class _ParticlesState extends State<Particles> {
   }
 
   _simulateParticles(Duration time) {
-    particles.forEach((particle) => particle.maintainRestart(time));
+    for (var particle in particles) {
+      particle.maintainRestart(time);
+    }
   }
 }
 
 class ParticleModel {
-  Animatable tween;
-  double size;
-  AnimationProgress animationProgress;
+  late Animatable tween;
+  late double size;
+  late AnimationProgress animationProgress;
   Random random;
 
   ParticleModel(this.random) {
@@ -113,13 +119,13 @@ class ParticlePainter extends CustomPainter {
   void paint(Canvas canvas, Size size) {
     final paint = Paint()..color = Colors.white.withAlpha(50);
 
-    particles.forEach((particle) {
+    for (var particle in particles) {
       var progress = particle.animationProgress.progress(time);
       final animation = particle.tween.transform(progress);
       final position =
           Offset(animation["x"] * size.width, animation["y"] * size.height);
       canvas.drawCircle(position, size.width * 0.2 * particle.size, paint);
-    });
+    }
   }
 
   @override
@@ -127,20 +133,24 @@ class ParticlePainter extends CustomPainter {
 }
 
 class AnimatedBackground extends StatelessWidget {
+  const AnimatedBackground({Key? key}) : super(key: key);
+
   @override
   Widget build(BuildContext context) {
     final tween = MultiTrackTween([
-      Track("color1").add(Duration(seconds: 3),
-          ColorTween(begin: Color(0xff8a113a), end: Colors.lightBlue.shade900)),
-      Track("color2").add(Duration(seconds: 3),
-          ColorTween(begin: Color(0xff440216), end: Colors.blue.shade600))
+      Track("color1").add(
+          const Duration(seconds: 3),
+          ColorTween(
+              begin: const Color(0xff8a113a), end: Colors.lightBlue.shade900)),
+      Track("color2").add(const Duration(seconds: 3),
+          ColorTween(begin: const Color(0xff440216), end: Colors.blue.shade600))
     ]);
 
     return ControlledAnimation(
       playback: Playback.MIRROR,
       tween: tween,
       duration: tween.duration,
-      builder: (context, animation) {
+      builder: (context, dynamic animation) {
         return Container(
           decoration: BoxDecoration(
               gradient: LinearGradient(
@@ -155,12 +165,12 @@ class AnimatedBackground extends StatelessWidget {
 
 class CenteredText extends StatelessWidget {
   const CenteredText({
-    Key key,
+    Key? key,
   }) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
-    return Center(
+    return const Center(
       child: Text(
         "Welcome to Flutter for web",
         style: TextStyle(color: Colors.white, fontWeight: FontWeight.w200),

web/particle_background/lib/simple_animations_package.dart

@@ -2,8 +2,9 @@
 //    https://pub.dev/packages/simple_animations
 
 import 'dart:math';
-import 'package:flutter/widgets.dart';
+
 import 'package:flutter/scheduler.dart';
+import 'package:flutter/widgets.dart';
 
 /// Widget to easily create a continuous animation.
 ///
@@ -22,16 +23,17 @@ import 'package:flutter/scheduler.dart';
 /// [startTimeSimulationTicks] property.)
 class Rendering extends StatefulWidget {
   final Widget Function(BuildContext context, Duration timeElapsed) builder;
-  final Function(Duration timeElapsed) onTick;
+  final Function(Duration timeElapsed)? onTick;
   final Duration startTime;
   final int startTimeSimulationTicks;
 
-  Rendering(
-      {this.builder,
+  const Rendering(
+      {required this.builder,
       this.onTick,
       this.startTime = Duration.zero,
-      this.startTimeSimulationTicks = 20})
-      : assert(builder != null, "Builder needs to defined.");
+      this.startTimeSimulationTicks = 20,
+      Key? key})
+      : super(key: key);
 
   @override
   _RenderingState createState() => _RenderingState();
@@ -39,8 +41,8 @@ class Rendering extends StatefulWidget {
 
 class _RenderingState extends State<Rendering>
     with SingleTickerProviderStateMixin {
-  Ticker _ticker;
-  Duration _timeElapsed = Duration(milliseconds: 0);
+  late Ticker _ticker;
+  Duration _timeElapsed = const Duration(milliseconds: 0);
 
   @override
   void initState() {
@@ -57,7 +59,7 @@ class _RenderingState extends State<Rendering>
 
   void _onRender(Duration effectiveElapsed) {
     if (widget.onTick != null) {
-      widget.onTick(effectiveElapsed);
+      widget.onTick!(effectiveElapsed);
     }
     setState(() {
       _timeElapsed = effectiveElapsed;
@@ -66,14 +68,14 @@ class _RenderingState extends State<Rendering>
 
   void _simulateStartTimeTicks() {
     if (widget.onTick != null) {
-      Iterable.generate(widget.startTimeSimulationTicks + 1).forEach((i) {
+      for (var i in Iterable.generate(widget.startTimeSimulationTicks + 1)) {
         final simulatedTime = Duration(
             milliseconds: (widget.startTime.inMilliseconds *
                     i /
                     widget.startTimeSimulationTicks)
                 .round());
-        widget.onTick(simulatedTime);
-      });
+        widget.onTick!(simulatedTime);
+      }
     }
   }
 
@@ -116,29 +118,28 @@ class _RenderingState extends State<Rendering>
 ///   );
 /// ```
 class MultiTrackTween extends Animatable<Map<String, dynamic>> {
-  final _tracksToTween = Map<String, _TweenData>();
+  final _tracksToTween = <String, _TweenData>{};
   var _maxDuration = 0;
 
   MultiTrackTween(List<Track> tracks)
-      : assert(tracks != null && tracks.length > 0,
-            "Add a List<Track> to configure the tween."),
-        assert(tracks.where((track) => track.items.length == 0).length == 0,
+      : assert(tracks.isNotEmpty, "Add a List<Track> to configure the tween."),
+        assert(tracks.where((track) => track.items.isEmpty).isEmpty,
             "Each Track needs at least one added Tween by using the add()-method.") {
     _computeMaxDuration(tracks);
     _computeTrackTweens(tracks);
   }
 
   void _computeMaxDuration(List<Track> tracks) {
-    tracks.forEach((track) {
+    for (var track in tracks) {
       final trackDuration = track.items
           .map((item) => item.duration.inMilliseconds)
           .reduce((sum, item) => sum + item);
       _maxDuration = max(_maxDuration, trackDuration);
-    });
+    }
   }
 
   void _computeTrackTweens(List<Track> tracks) {
-    tracks.forEach((track) {
+    for (var track in tracks) {
       final trackDuration = track.items
           .map((item) => item.duration.inMilliseconds)
           .reduce((sum, item) => sum + item);
@@ -159,7 +160,7 @@ class MultiTrackTween extends Animatable<Map<String, dynamic>> {
 
       _tracksToTween[track.name] =
           _TweenData(tween: sequence, maxTime: trackDuration / _maxDuration);
-    });
+    }
   }
 
   /// Returns the highest duration specified by [Track]s.
@@ -186,10 +187,10 @@ class MultiTrackTween extends Animatable<Map<String, dynamic>> {
 
   @override
   Map<String, dynamic> transform(double t) {
-    final Map<String, dynamic> result = Map();
+    final Map<String, dynamic> result = {};
     _tracksToTween.forEach((name, tweenData) {
-      final double tTween = max(0, min(t, tweenData.maxTime - 0.0001));
-      result[name] = tweenData.tween.transform(tTween);
+      final double tTween = max(0, min(t, tweenData.maxTime! - 0.0001));
+      result[name] = tweenData.tween!.transform(tTween);
     });
     return result;
   }
@@ -200,7 +201,7 @@ class Track<T> {
   final String name;
   final List<_TrackItem> items = [];
 
-  Track(this.name) : assert(name != null, "Track name must not be null.");
+  Track(this.name);
 
   /// Adds a "piece of animation" to a [Track].
   ///
@@ -209,7 +210,7 @@ class Track<T> {
   ///
   /// Optionally you can set a named parameter [curve] that applies an easing
   /// curve to the tween.
-  Track<T> add(Duration duration, Animatable<T> tween, {Curve curve}) {
+  Track<T> add(Duration duration, Animatable<T> tween, {Curve? curve}) {
     items.add(_TrackItem(duration, tween, curve: curve));
     return this;
   }
@@ -217,11 +218,9 @@ class Track<T> {
 
 class _TrackItem<T> {
   final Duration duration;
-  Animatable<T> tween;
+  late Animatable<T> tween;
 
-  _TrackItem(this.duration, Animatable<T> _tween, {Curve curve})
-      : assert(duration != null, "Please set a duration."),
-        assert(_tween != null, "Please set a tween.") {
+  _TrackItem(this.duration, Animatable<T> _tween, {Curve? curve}) {
     if (curve != null) {
       tween = _tween.chain(CurveTween(curve: curve));
     } else {
@@ -231,8 +230,8 @@ class _TrackItem<T> {
 }
 
 class _TweenData<T> {
-  final Animatable<T> tween;
-  final double maxTime;
+  final Animatable<T>? tween;
+  final double? maxTime;
 
   _TweenData({this.tween, this.maxTime});
 }
@@ -305,31 +304,27 @@ class ControlledAnimation<T> extends StatefulWidget {
   final Animatable<T> tween;
   final Curve curve;
   final Duration duration;
-  final Duration delay;
-  final Widget Function(BuildContext buildContext, T animatedValue) builder;
-  final Widget Function(BuildContext, Widget child, T animatedValue)
+  final Duration? delay;
+  final Widget Function(BuildContext buildContext, T animatedValue)? builder;
+  final Widget Function(BuildContext, Widget? child, T animatedValue)?
       builderWithChild;
-  final Widget child;
-  final AnimationStatusListener animationControllerStatusListener;
+  final Widget? child;
+  final AnimationStatusListener? animationControllerStatusListener;
   final double startPosition;
 
-  ControlledAnimation(
+  const ControlledAnimation(
       {this.playback = Playback.PLAY_FORWARD,
-      this.tween,
+      required this.tween,
       this.curve = Curves.linear,
-      this.duration,
+      required this.duration,
       this.delay,
       this.builder,
       this.builderWithChild,
       this.child,
       this.animationControllerStatusListener,
       this.startPosition = 0.0,
-      Key key})
-      : assert(duration != null,
-            "Please set property duration. Example: Duration(milliseconds: 500)"),
-        assert(tween != null,
-            "Please set property tween. Example: Tween(from: 0.0, to: 100.0)"),
-        assert(
+      Key? key})
+      : assert(
             (builderWithChild != null && child != null && builder == null) ||
                 (builder != null && builderWithChild == null && child == null),
             "Either use just builder and keep buildWithChild and child null. "
@@ -346,8 +341,8 @@ class ControlledAnimation<T> extends StatefulWidget {
 
 class _ControlledAnimationState<T> extends State<ControlledAnimation>
     with SingleTickerProviderStateMixin {
-  AnimationController _controller;
-  Animation<T> _animation;
+  late AnimationController _controller;
+  late Animation<T?> _animation;
   bool _isDisposed = false;
   bool _waitForDelay = true;
   bool _isCurrentlyMirroring = false;
@@ -362,19 +357,19 @@ class _ControlledAnimationState<T> extends State<ControlledAnimation>
 
     _animation = widget.tween
         .chain(CurveTween(curve: widget.curve))
-        .animate(_controller);
+        .animate(_controller) as Animation<T?>;
 
     if (widget.animationControllerStatusListener != null) {
-      _controller.addStatusListener(widget.animationControllerStatusListener);
+      _controller.addStatusListener(widget.animationControllerStatusListener!);
     }
 
     initialize();
     super.initState();
   }
 
-  void initialize() async {
+  Future<void> initialize() async {
     if (widget.delay != null) {
-      await Future.delayed(widget.delay);
+      await Future.delayed(widget.delay!);
     }
     _waitForDelay = false;
     executeInstruction();
@@ -387,7 +382,7 @@ class _ControlledAnimationState<T> extends State<ControlledAnimation>
     super.didUpdateWidget(oldWidget);
   }
 
-  void executeInstruction() async {
+  Future<void> executeInstruction() async {
     if (_isDisposed || _waitForDelay) {
       return;
     }
@@ -423,9 +418,9 @@ class _ControlledAnimationState<T> extends State<ControlledAnimation>
   @override
   Widget build(BuildContext context) {
     if (widget.builder != null) {
-      return widget.builder(context, _animation.value);
+      return widget.builder!(context, _animation.value);
     } else if (widget.builderWithChild != null && widget.child != null) {
-      return widget.builderWithChild(context, widget.child, _animation.value);
+      return widget.builderWithChild!(context, widget.child, _animation.value);
     }
     _controller.stop(canceled: true);
     throw FlutterError(
@@ -452,10 +447,7 @@ class AnimationProgress {
   final Duration startTime;
 
   /// Creates an [AnimationProgress].
-  AnimationProgress({this.duration, this.startTime})
-      : assert(duration != null, "Please specify an animation duration."),
-        assert(
-            startTime != null, "Please specify a start time of the animation.");
+  AnimationProgress({required this.duration, required this.startTime});
 
   /// Queries the current progress value based on the specified [startTime] and
   /// [duration] as a value between `0.0` and `1.0`. It will automatically

web/particle_background/pubspec.lock

@@ -20,6 +20,20 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_lints:
+    dependency: "direct main"
+    description:
+      name: flutter_lints
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.4"
+  lints:
+    dependency: transitive
+    description:
+      name: lints
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.1"
   meta:
     dependency: transitive
     description:

web/particle_background/pubspec.yaml

@@ -3,11 +3,12 @@ description: Example for the simple_animations package
 homepage: https://github.com/felixblaschke/simple_animations
 
 environment:
-  sdk: ">=2.2.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   flutter:
     sdk: flutter
+  flutter_lints: ^1.0.4
 flutter:
   assets:
     - preview.png