Initial checkin of Rive 2 runtime.

example/lib/main.dart

@@ -0,0 +1,84 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:rive/rive.dart';
+
+void main() {
+  runApp(MyApp());
+}
+
+class MyApp extends StatefulWidget {
+  @override
+  _MyAppState createState() => _MyAppState();
+}
+
+class _MyAppState extends State<MyApp> with SingleTickerProviderStateMixin {
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      home: MyHomePage(),
+    );
+  }
+}
+
+class MyHomePage extends StatefulWidget {
+  const MyHomePage({Key key}) : super(key: key);
+
+  @override
+  _MyHomePageState createState() => _MyHomePageState();
+}
+
+class _MyHomePageState extends State<MyHomePage> {
+  void _togglePlay() {
+    setState(() => _controller.isActive = !_controller.isActive);
+  }
+
+  /// We track if the animation is playing by whether or not the controller is
+  /// running.
+  bool get isPlaying => _controller?.isActive ?? false;
+
+  Artboard _riveArtboard;
+  RiveAnimationController _controller;
+  @override
+  void initState() {
+    super.initState();
+
+    // Load the animation file from the bundle, note that you could also
+    // download this. The RiveFile just expects a list of bytes.
+    rootBundle.load('assets/colors_juice.riv').then(
+      (data) async {
+        var file = RiveFile();
+        // Load the RiveFile from the binary data.
+        var success = file.import(data);
+        if (success) {
+          // The artboard is the root of the animation and is what gets drawn
+          // into the Rive widget.
+          var artboard = file.mainArtboard;
+          // Add a controller to play back a known animation on the main/default
+          // artboard.We store a reference to it so we can toggle playback.
+          artboard.addController(
+            _controller = SimpleAnimation('walk'),
+          );
+          setState(() => _riveArtboard = artboard);
+        }
+      },
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: Center(
+        child: _riveArtboard == null
+            ? const SizedBox()
+            : Rive(artboard: _riveArtboard),
+      ),
+      floatingActionButton: FloatingActionButton(
+        onPressed: _togglePlay,
+        tooltip: isPlaying ? 'Pause' : 'Play',
+        child: Icon(
+          isPlaying ? Icons.pause : Icons.play_arrow,
+        ),
+      ),
+    );
+  }
+}