add initState, rename animated_container

sky/sdk/example/widgets/card_collection.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:sky' as sky;
 
 import 'package:vector_math/vector_math.dart';
 import 'package:sky/animation/animation_performance.dart';
 import 'package:sky/animation/scroll_behavior.dart';
 import 'package:sky/base/lerp.dart';
 import 'package:sky/painting/text_style.dart';
 import 'package:sky/theme/colors.dart';
-import 'package:sky/widgets/animated_container.dart';
+import 'package:sky/widgets/animation_builder.dart';
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/widgets/block_viewport.dart';
 import 'package:sky/widgets/card.dart';
 import 'package:sky/widgets/scaffold.dart';
 import 'package:sky/widgets/scrollable.dart';
 import 'package:sky/widgets/theme.dart';
 import 'package:sky/widgets/tool_bar.dart';
 import 'package:sky/widgets/widget.dart';
 
 
@@ skipping 47 matching lines @@
 
   final List<double> cardHeights = [
     48.0, 64.0, 82.0, 46.0, 60.0, 55.0, 84.0, 96.0, 50.0,
     48.0, 64.0, 82.0, 46.0, 60.0, 55.0, 84.0, 96.0, 50.0,
     48.0, 64.0, 82.0, 46.0, 60.0, 55.0, 84.0, 96.0, 50.0
   ];
 
   List<int> visibleCardIndices;
 
   CardCollectionApp() {
-    _activeCardTransform = new AnimatedContainer()
+    _activeCardTransform = new AnimationBuilder()
       ..position = new AnimatedType<Point>(Point.origin)
       ..opacity = new AnimatedType<double>(1.0, end: 0.0);
 
     _activeCardAnimation = _activeCardTransform.createPerformance(
         [_activeCardTransform.position, _activeCardTransform.opacity],
         duration: new Duration(milliseconds: _kCardDismissFadeoutMS));
     _activeCardAnimation.addListener(_handleAnimationProgressChanged);
 
     visibleCardIndices = new List.generate(cardHeights.length, (i) => i);
   }
 
   int _activeCardIndex = -1;
-  AnimatedContainer _activeCardTransform;
+  AnimationBuilder _activeCardTransform;
   AnimationPerformance _activeCardAnimation;
   double _activeCardWidth;
   double _activeCardDragX = 0.0;
   bool _activeCardDragUnderway = false;
 
   Point get _activeCardDragEndPoint {
     return new Point(_activeCardDragX.sign * _activeCardWidth * _kDismissCardThreshold, 0.0);
   }
 
   void _handleAnimationProgressChanged() {
@@ skipping 116 matching lines @@
     return new Scaffold(
       toolbar: new ToolBar(center: new Text('Swipe Away')),
       body: new SizeObserver(child: cardCollection, callback: _handleSizeChanged)
     );
   }
 }
 
 void main() {
   runApp(new CardCollectionApp());
 }