Easing Animation

easinganimation_step2.dart

class EasingAnimationWidget extends StatefulWidget {
  @override
  EasingAnimationWidgetState createState() => EasingAnimationWidgetState();
}

class EasingAnimationWidgetState extends State<EasingAnimationWidget> 
  with TickerProviderStateMixin {  
  
  AnimationController _controller;
  Animation _animation;
  
  @override
  void initState() {
    super.initState();

    _controller =
        AnimationController(vsync: this, duration: Duration(seconds: 2));

    _animation = Tween(begin: -1.0, end: 0.0).animate(CurvedAnimation(
      parent: _controller,
      curve: Curves.fastOutSlowIn,
    ));
  }
  @override
  Widget build(BuildContext context) {
    final double width = MediaQuery.of(context).size.width;
    return AnimatedBuilder(
        animation: _controller,
        builder: (BuildContext context, Widget child) {
          return Scaffold(
              body: Transform(
                transform:
                Matrix4.translationValues(_animation.value * width, 0.0, 0.0),
                child: new Center(
                    child: Container(
                      width: 200.0,
                      height: 200.0,
                      color: Colors.black12,
                    )),
              ));
        });
  }
  
  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }
}