tablet-app/lib/main.dart

import 'package:flutter/material.dart';
import 'package:managerapi/api.dart';
import 'package:provider/provider.dart';
import 'package:tablet_app/client.dart';
import 'Helpers/DatabaseHelper.dart';
import 'Models/tabletContext.dart';
import 'Screens/Configuration/config_view.dart';
import 'Screens/MainView/main_view.dart';
import 'Screens/Previous/previous_view.dart';
import 'app_context.dart';
import 'constants.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  String initialRoute;
  TabletAppContext localContext = new TabletAppContext();
  bool isConfig = false;

  localContext = await DatabaseHelper.instance.getData();

  if(localContext != null) {
    print("we've got an local db !");
    localContext.clientAPI = new Client(localContext.host);
    isConfig = localContext.configuration != null;
    print(localContext);
    // Get config from manager
    DeviceDetailDTO device = await localContext.clientAPI.deviceApi.deviceGetDetail(localContext.deviceId);
    localContext.configuration.id = device.configurationId;
    if (device.configurationId == null) {
      print("device.configurationId == null");
      localContext.configuration = null;
      isConfig = false;
    }
  } else {
    print("NO LOCAL DB !");
  }

  initialRoute = isConfig ? '/main' : '/config';

  final MyApp myApp = MyApp(
    initialRoute: initialRoute,
    tabletAppContext: localContext,
  );
  runApp(myApp);
}

class MyApp extends StatefulWidget {
  final String initialRoute;
  final TabletAppContext tabletAppContext;
  MyApp({this.initialRoute, this.tabletAppContext});

  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  TabletAppContext tabletAppContext;

  @override
  void initState() {
    //tabletAppContext = widget.tabletAppContext;
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider<AppContext>(
      create: (_) => AppContext(widget.tabletAppContext),
      child: MaterialApp(
        debugShowCheckedModeBanner: false,
        title: 'Tablet App Demo',
        initialRoute: widget.initialRoute,
        /*supportedLocales: [
          const Locale('en', 'US'),
          const Locale('fr', 'FR'),
        ],*/
        theme: ThemeData(
          primarySwatch: Colors.grey,
          scaffoldBackgroundColor: kBackgroundGrey,
          //fontFamily: "Vollkorn",
          textTheme: TextTheme(bodyText1: TextStyle(color: kMainRed)),
          visualDensity: VisualDensity.adaptivePlatformDensity,
        ),
        routes: {
          '/previous': (context) => PreviousViewWidget(title: 'Tablet App Demo Home Page'),
          '/main': (context) => MainViewWidget(),
          '/config': (context) => ConfigViewWidget(),
        }
      ),
    );
  }
}