shaking-button-scoped-model-flutter-example-quick

import 'package:flutter/material.dart';
import 'package:flutter/animation.dart';
import 'package:scoped_model/scoped_model.dart';

void main() {
  runApp(MaterialApp(
    title: 'Example',
    home: MyApp(),
  ));
}

class MyApp extends StatefulWidget {
  @override
  MyAppState createState() => MyAppState();
}

class MyAppState extends State<MyApp> with SingleTickerProviderStateMixin {
  Animation animation;
  AnimationController animationController;

  @override
  void initState() {
    animationController =
        AnimationController(duration: Duration(milliseconds: 100), vsync: this);
    animation = Tween(begin: 0.0, end: 50.0).animate(animationController);
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    final model = AppModel(animation, animationController);
    return Scaffold(
        body: ScopedModel<AppModel>(
            model: model,
            child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: <Widget>[
                  ButtonAnimation(),
                  Container(
                    width: 100.0,
                    height: 100.0,
                  ),
                  RaisedButton(
                    child: Text('Stop Animation'),
                    onPressed: () {
                      animationController.stop();
                    },
                  )
                ])));
  }

  @override
  void dispose() {
    animationController.dispose();
    super.dispose();
  }
}

class ButtonAnimation extends StatefulWidget {
  @override
  ButtonState createState() => ButtonState();
}

class ButtonState extends State<ButtonAnimation> {
  @override
  Widget build(BuildContext context) {
    return ScopedModelDescendant<AppModel>(
        builder: (context, child, model) => Center(
              child: Container(
                margin: EdgeInsets.only(left: model.animation.value ?? 0.0),
                child: RaisedButton(
                  child: Text("Push Me"),
                  onPressed: () {
                    model.animation.addListener(() => setState(() {}));
                    model.onPressed();
                  },
                ),
              ),
            ));
  }
}

class AppModel extends Model {
  final Animation animation;
  final AnimationController animationController;

  AppModel._({this.animation, this.animationController});

  factory AppModel(Animation anim, AnimationController controller) {
    return AppModel._(animation: anim, animationController: controller);
  }

  void onPressed() {
    animation.addStatusListener((status) {
      if (status == AnimationStatus.completed) {
        animationController.reverse();
      } else if (status == AnimationStatus.dismissed) {
        animationController.forward();
      }
    });
    animationController.forward();
    print('Pushed the Button');
    print(animation.value.toString());
  }
}