Tidying up add-to-app samples (#160)

experimental/add_to_app/flutter_module_using_plugin/build.gradle

@@ -1 +0,0 @@
-buildscript {}

experimental/add_to_app/flutter_module_using_plugin/lib/main.dart

@@ -7,7 +7,10 @@ import 'package:flutter/services.dart';
 import 'package:provider/provider.dart';
 import 'package:url_launcher/url_launcher.dart' as launcher;
 
+/// The entrypoint for the flutter module.
 void main() {
+  // This call ensures the Flutter binding has been set up before creating the
+  // MethodChannel-based model.
   WidgetsFlutterBinding.ensureInitialized();
 
   final model = CounterModel();
@@ -20,6 +23,13 @@ void main() {
   );
 }
 
+/// A simple model that uses a [MethodChannel] as the source of truth for the
+/// state of the counter.
+///
+/// Rather than storing app state data within the Flutter module itself (where
+/// the native portions of the app can't access it), this module passes messages
+/// back to the containing app whenever it needs to increment or retrieve the
+/// value of the counter.
 class CounterModel extends ChangeNotifier {
   CounterModel() {
     _channel.setMethodCallHandler(_handleMessage);
@@ -44,6 +54,10 @@ class CounterModel extends ChangeNotifier {
   }
 }
 
+/// The "app" displayed by this module.
+///
+/// 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 {
   @override
   Widget build(BuildContext context) {
@@ -57,6 +71,8 @@ class MyApp extends StatelessWidget {
   }
 }
 
+/// Wraps [Contents] in a Material [Scaffold] so it looks correct when displayed
+/// full-screen.
 class FullScreenView extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
@@ -69,6 +85,12 @@ class FullScreenView extends StatelessWidget {
   }
 }
 
+/// The actual content displayed by the module.
+///
+/// This widget displays info about the state of a counter and how much room (in
+/// logical pixels) it's been given. It also offers buttons to increment the
+/// counter, opening the Flutter documentation via the url_launcher plugin, and
+/// (optionally) close the Flutter view.
 class Contents extends StatelessWidget {
   final bool showExit;
 
@@ -126,6 +148,8 @@ class Contents extends StatelessWidget {
                 ),
                 RaisedButton(
                   onPressed: () async {
+                    // Use the url_launcher plugin to open the Flutter docs in
+                    // a browser.
                     final url = 'https://flutter.dev/docs';
                     if (await launcher.canLaunch(url)) {
                       launcher.launch(url);

experimental/add_to_app/flutter_module_using_plugin/pubspec.lock

@@ -115,7 +115,7 @@ packages:
       name: provider
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "3.1.0"
+    version: "3.1.0+1"
   quiver:
     dependency: transitive
     description:
@@ -183,7 +183,14 @@ packages:
       name: url_launcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "5.2.0"
+    version: "5.2.5"
+  url_launcher_platform_interface:
+    dependency: transitive
+    description:
+      name: url_launcher_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.1"
   vector_math:
     dependency: transitive
     description:
@@ -199,5 +206,5 @@ packages:
     source: hosted
     version: "3.5.0"
 sdks:
-  dart: ">=2.5.0 <3.0.0"
-  flutter: ">=1.5.0 <2.0.0"
+  dart: ">=2.6.0-dev <3.0.0"
+  flutter: ">=1.9.1+hotfix.4 <2.0.0"

experimental/add_to_app/flutter_module_using_plugin/pubspec.yaml

@@ -4,13 +4,13 @@ description: An example Flutter module that uses a plugin.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.5.0 <3.0.0"
+  sdk: ">=2.6.0-dev <3.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
   provider: ^3.1.0
-  url_launcher: ^5.1.6
+  url_launcher: ^5.2.5
 
 dev_dependencies:
   flutter_test: