add two demos, set up routing

animations/lib/main.dart

@@ -1,111 +1,84 @@
 import 'package:flutter/material.dart';
+import 'src/basics/animation_controller_demo.dart';
+import 'src/misc/expand_card.dart';
 
-void main() => runApp(MyApp());
+void main() => runApp(AnimationsSamples());
 
-class MyApp extends StatelessWidget {
+class Demo {
-  // This widget is the root of your application.
+  final String name;
-  @override
+  final String route;
-  Widget build(BuildContext context) {
+  final WidgetBuilder builder;
-    return MaterialApp(
+
-      title: 'Flutter Demo',
+  Demo(this.name, this.route, this.builder);
-      theme: ThemeData(
-        // This is the theme of your application.
-        //
-        // Try running your application with "flutter run". You'll see the
-        // application has a blue toolbar. Then, without quitting the app, try
-        // changing the primarySwatch below to Colors.green and then invoke
-        // "hot reload" (press "r" in the console where you ran "flutter run",
-        // or simply save your changes to "hot reload" in a Flutter IDE).
-        // Notice that the counter didn't reset back to zero; the application
-        // is not restarted.
-        primarySwatch: Colors.blue,
-      ),
-      home: MyHomePage(title: 'Flutter Demo Home Page'),
-    );
-  }
 }
 
-class MyHomePage extends StatefulWidget {
+List<Demo> basicDemos = [
-  MyHomePage({Key key, this.title}) : super(key: key);
+  Demo('Animation Controller', AnimationControllerDemo.routeName,
+      (context) => AnimationControllerDemo()),
+];
 
-  // This widget is the home page of your application. It is stateful, meaning
+List<Demo> miscDemos = [
-  // that it has a State object (defined below) that contains fields that affect
+  Demo('Expandable Card', ExpandCardDemo.routeName,
-  // how it looks.
+      (context) => ExpandCardDemo()),
+];
 
-  // This class is the configuration for the state. It holds the values (in this
+Map<String, WidgetBuilder> basicDemoRoutes = Map.fromEntries(
-  // case the title) provided by the parent (in this case the App widget) and
+    basicDemos.map((d) => MapEntry(d.route, d.builder)));
-  // used by the build method of the State. Fields in a Widget subclass are
-  // always marked "final".
 
-  final String title;
+Map<String, WidgetBuilder> miscDemoRoutes = Map.fromEntries(
+    miscDemos.map((d) => MapEntry(d.route, d.builder)));
 
-  @override
+Map<String, WidgetBuilder> allRoutes = <String, WidgetBuilder>{
-  _MyHomePageState createState() => _MyHomePageState();
+  ...basicDemoRoutes,
-}
+  ...miscDemoRoutes,
+};
 
-class _MyHomePageState extends State<MyHomePage> {
+class AnimationsSamples extends StatelessWidget {
-  int _counter = 0;
+  Widget build(BuildContext context) {
 
-  void _incrementCounter() {
+    return MaterialApp(
-    setState(() {
+      title: 'Animations Samples',
-      // This call to setState tells the Flutter framework that something has
+      theme: ThemeData(
-      // changed in this State, which causes it to rerun the build method below
+        primarySwatch: Colors.deepPurple,
-      // so that the display can reflect the updated values. If we changed
+      ),
-      // _counter without calling setState(), then the build method would not be
+      routes: allRoutes,
-      // called again, and so nothing would appear to happen.
+      home: HomePage(),
-      _counter++;
+    );
-    });
   }
+}
+
+class HomePage extends StatelessWidget {
+  final TextStyle _headerStyle =
+      TextStyle(fontWeight: FontWeight.bold, fontSize: 24);
 
-  @override
   Widget build(BuildContext context) {
-    // This method is rerun every time setState is called, for instance as done
-    // by the _incrementCounter method above.
-    //
-    // The Flutter framework has been optimized to make rerunning build methods
-    // fast, so that you can just rebuild anything that needs updating rather
-    // than having to individually change instances of widgets.
     return Scaffold(
       appBar: AppBar(
-        // Here we take the value from the MyHomePage object that was created by
+        title: Text('Animation Examples'),
-        // the App.build method, and use it to set our appbar title.
-        title: Text(widget.title),
       ),
-      body: Center(
+      body: ListView(
-        // Center is a layout widget. It takes a single child and positions it
+        children: <Widget>[
-        // in the middle of the parent.
+          ListTile(title: Text('Basics', style: _headerStyle)),
-        child: Column(
+          ...basicDemos.map((d) => DemoTile(d)),
-          // Column is also layout widget. It takes a list of children and
+          ListTile(title: Text('Misc', style: _headerStyle)),
-          // arranges them vertically. By default, it sizes itself to fit its
+          ...miscDemos.map((d) => DemoTile(d)),
-          // children horizontally, and tries to be as tall as its parent.
+        ],
-          //
-          // Invoke "debug painting" (press "p" in the console, choose the
-          // "Toggle Debug Paint" action from the Flutter Inspector in Android
-          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
-          // to see the wireframe for each widget.
-          //
-          // Column has various properties to control how it sizes itself and
-          // how it positions its children. Here we use mainAxisAlignment to
-          // center the children vertically; the main axis here is the vertical
-          // axis because Columns are vertical (the cross axis would be
-          // horizontal).
-          mainAxisAlignment: MainAxisAlignment.center,
-          children: <Widget>[
-            Text(
-              'You have pushed the button this many times:',
-            ),
-            Text(
-              '$_counter',
-              style: Theme.of(context).textTheme.display1,
-            ),
-          ],
-        ),
       ),
-      floatingActionButton: FloatingActionButton(
+    );
-        onPressed: _incrementCounter,
+  }
-        tooltip: 'Increment',
+}
-        child: Icon(Icons.add),
+
-      ), // This trailing comma makes auto-formatting nicer for build methods.
+class DemoTile extends StatelessWidget {
+  final Demo demo;
+
+  DemoTile(this.demo);
+
+  Widget build(BuildContext context) {
+    return ListTile(
+      title: Text(demo.name),
+      onTap: () {
+        Navigator.pushNamed(context, demo.route);
+      },
     );
   }
 }

animations/lib/src/basics/animation_controller_demo.dart

@@ -0,0 +1,61 @@
+import 'package:flutter/material.dart';
+
+class AnimationControllerDemo extends StatefulWidget {
+  static const String routeName = '/basics/animation_controller';
+
+  _AnimationControllerDemoState createState() =>
+      _AnimationControllerDemoState();
+}
+
+class _AnimationControllerDemoState extends State<AnimationControllerDemo>
+    with SingleTickerProviderStateMixin {
+  static const Duration _duration = Duration(seconds: 1);
+  AnimationController controller;
+
+  void initState() {
+    super.initState();
+
+    controller = AnimationController(vsync: this, duration: _duration)
+      ..addListener(() {
+        // Marks the widget tree as dirty
+        setState(() {});
+      });
+  }
+
+  void dispose() {
+    super.dispose();
+    controller.dispose();
+  }
+
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(),
+      body: Center(
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          children: <Widget>[
+            ConstrainedBox(
+              constraints: BoxConstraints(maxWidth: 200),
+              child: Text('${controller.value.toStringAsFixed(2)}',
+                  style: TextStyle(fontSize: 24)),
+            ),
+            MaterialButton(
+              color: Theme.of(context).primaryColor,
+              child: Text(
+                'animate',
+                style: TextStyle(color: Colors.white),
+              ),
+              onPressed: () {
+                if (controller.status == AnimationStatus.completed) {
+                  controller.reverse();
+                } else {
+                  controller.forward();
+                }
+              },
+            )
+          ],
+        ),
+      ),
+    );
+  }
+}

animations/lib/src/misc/expand_card.dart

@@ -0,0 +1,82 @@
+import 'package:flutter/material.dart';
+
+class ExpandCardDemo extends StatelessWidget {
+  static String routeName = '/simple_expandable_card';
+
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text('Simple Expandable Card'),
+      ),
+      body: Center(
+        child: SimpleExpandableCard(),
+      ),
+    );
+  }
+}
+
+class SimpleExpandableCard extends StatefulWidget {
+  _SimpleExpandableCardState createState() => _SimpleExpandableCardState();
+}
+
+class _SimpleExpandableCardState extends State<SimpleExpandableCard>
+    with SingleTickerProviderStateMixin {
+  static const Duration duration = Duration(milliseconds: 300);
+  bool expanded = false;
+
+  void initState() {
+    super.initState();
+  }
+
+  void _toggleExpanded() {
+    setState(() {
+      expanded = !expanded;
+    });
+  }
+
+  double get size => expanded ? 200 : 100;
+
+  Widget build(context) {
+    return GestureDetector(
+      onTap: () => _toggleExpanded(),
+      child: Card(
+        child: AnimatedCrossFade(
+          alignment: Alignment.center,
+          duration: duration,
+          crossFadeState:
+          expanded ? CrossFadeState.showSecond : CrossFadeState.showFirst,
+          firstChild: _ImageContainer(
+              size: size, image: 'assets/wolf.jpg', duration: duration),
+          secondChild: _ImageContainer(
+              size: size, image: 'assets/cat.jpg', duration: duration),
+        ),
+      ),
+    );
+  }
+}
+
+class _ImageContainer extends StatelessWidget {
+  final double size;
+  final String image;
+  final Duration duration;
+
+  _ImageContainer({this.size, this.image, this.duration});
+
+  Widget build(BuildContext context) {
+    return Padding(
+      padding: const EdgeInsets.all(8.0),
+      child: AnimatedContainer(
+        duration: duration,
+        width: size,
+        height: size,
+        decoration: BoxDecoration(
+          color: Colors.transparent,
+          image: DecorationImage(
+            fit: BoxFit.cover,
+            image: AssetImage(image),
+          ),
+        ),
+      ),
+    );
+  }
+}

animations/pubspec.lock

@@ -143,4 +143,4 @@ packages:
     source: hosted
     version: "2.0.8"
 sdks:
-  dart: ">=2.2.2 <3.0.0"
+  dart: ">=2.3.0 <3.0.0"

animations/pubspec.yaml

@@ -1,72 +1,18 @@
 name: animations
 description: A new Flutter project.
-
-# The following defines the version and build number for your application.
-# A version number is three numbers separated by dots, like 1.2.43
-# followed by an optional build number separated by a +.
-# Both the version and the builder number may be overridden in flutter
-# build by specifying --build-name and --build-number, respectively.
-# In Android, build-name is used as versionName while build-number used as versionCode.
-# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
-# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
-# Read more about iOS versioning at
-# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: ">=2.3.0 <3.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
-
-  # The following adds the Cupertino Icons font to your application.
-  # Use with the CupertinoIcons class for iOS style icons.
   cupertino_icons: ^0.1.2
-
 dev_dependencies:
   flutter_test:
     sdk: flutter
-
-
-# For information on the generic Dart part of this file, see the
-# following page: https://dart.dev/tools/pub/pubspec
-
-# The following section is specific to Flutter.
 flutter:
-
-  # The following line ensures that the Material Icons font is
-  # included with your application, so that you can use the icons in
-  # the material Icons class.
   uses-material-design: true
-
+  assets:
-  # To add assets to your application, add an assets section, like this:
+    - assets/
-  # assets:
-  #  - images/a_dot_burr.jpeg
-  #  - images/a_dot_ham.jpeg
-
-  # An image asset can refer to one or more resolution-specific "variants", see
-  # https://flutter.dev/assets-and-images/#resolution-aware.
-
-  # For details regarding adding assets from package dependencies, see
-  # https://flutter.dev/assets-and-images/#from-packages
-
-  # To add custom fonts to your application, add a fonts section here,
-  # in this "flutter" section. Each entry in this list should have a
-  # "family" key with the font family name, and a "fonts" key with a
-  # list giving the asset and other descriptors for the font. For
-  # example:
-  # fonts:
-  #   - family: Schyler
-  #     fonts:
-  #       - asset: fonts/Schyler-Regular.ttf
-  #       - asset: fonts/Schyler-Italic.ttf
-  #         style: italic
-  #   - family: Trajan Pro
-  #     fonts:
-  #       - asset: fonts/TrajanPro.ttf
-  #       - asset: fonts/TrajanPro_Bold.ttf
-  #         weight: 700
-  #
-  # For details regarding fonts from package dependencies,
-  # see https://flutter.dev/custom-fonts/#from-packages

animations/test/widget_test.dart

@@ -1,30 +0,0 @@
-// 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:animations/main.dart';
-
-void main() {
-  testWidgets('Counter increments smoke test', (WidgetTester tester) async {
-    // Build our app and trigger a frame.
-    await tester.pumpWidget(MyApp());
-
-    // Verify that our counter starts at 0.
-    expect(find.text('0'), findsOneWidget);
-    expect(find.text('1'), 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);
-  });
-}