flutter example navigation with scopedModel

main.dart

import 'dart:async';

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

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}


class MyHomePage extends StatelessWidget {
  final String title;
  MyHomePage({Key key, this.title}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text(title),
      ),
      body: FutureBuilder(
        future: getFuture(),
        builder: (context, snapshot) => _buildView(snapshot.data, context),
      ),
    );
  }

  Widget _buildView(String data, BuildContext context) {
    return ScopedModel<MyModel>(
      model: MyModel(data),
      child: new Center(
        child: new Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            ScopedModelDescendant<MyModel>(
              builder: (context, child, model) =>
              RaisedButton(
                onPressed: () => goNext(context, model._name, model),
                child: Text("go next"),
              ),
            ),
            ScopedModelDescendant<MyModel>(
              builder: (context, child, model) =>
                  Text("${model._names.length}")
            )
          ],
        ),
      ),
    );
  }

  void goNext(BuildContext context, String titleFromFuture, MyModel model){
    Navigator.of(context).push(MaterialPageRoute(builder: (context) => SecondScreen(title: titleFromFuture, model: model,)));
  }

  Future<String> getFuture() async {
    await Future.delayed(Duration(seconds: 2));
    return "Screen with model";
  }
}

class SecondScreen extends StatelessWidget {
  final String title;
  final MyModel model;
  SecondScreen({Key key, this.title, this.model}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return ScopedModel<MyModel>(
      model: model,
      child: new Scaffold(
        appBar: new AppBar(
          title: new Text(title),
        ),
        body: new Center(
          child: new Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              RaisedButton(
                onPressed: () => showMyDialog(title, context, model),
                child: Text("open dialog"),
              ),
              ScopedModelDescendant<MyModel>(
                  builder: (context, child, model) =>
                      Text("${model._names.length}")
              )
            ],
          ),
        ),
      ),
    );
  }

  void showMyDialog(String name, BuildContext cont, MyModel model){
    showDialog(
        context: cont,
        builder: (context) => AlertDialog(
          title: Text(name),
          actions: <Widget>[
            RaisedButton(
              onPressed: () {
                Navigator.of(context).pop();
                model.addCallback(name);
                },
              child: Text("Ok"),
            )
          ],
        )
    );
  }
}

class MyModel extends Model{
  final String _name;
  final List<String> _names = List<String>();

  MyModel(this._name);

  void addCallback(String name){
    _names.add(name);
    notifyListeners();
  }
}