class Autentificacion extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final Auth auth = Provider.of(context).auth;
    return StreamBuilder<String>(
      stream: auth.onAuthStateChanged,
      builder: (context, AsyncSnapshot<String> snapshot) {
        if (snapshot.connectionState == ConnectionState.active) {
          final bool loggedIn = snapshot.hasData;
          if (loggedIn == true) {
            return Home();
          } else {
            return Inicio_sesion();
          }
        }
        return CircularProgressIndicator();
      },
    );
  }
}

int _SelectDrawerItem = 0;
_getDrawerItemWidget(int pos) {
    switch (pos) {
      case 0:
        return PruebaPantalla();
      case 1:
        return Play_List(null);
    }
  }

@override
  Widget build(BuildContext context) {
    cargarData();
    // print('userId de sharedPreferens =>${userId}');
    return Scaffold(
      appBar: AppBar(
        title: Text(titulo),
      ),
      drawer: Drawer(
        child: ListView(...),
      ),
      body: _getDrawerItemWidget(_SelectDrawerItem),
);

class _PruebaPantallaState extends State<PruebaPantalla> {
  int count = 0;
  @override
  Widget build(BuildContext context) {
    print("6.-Pantalla prueba");
    // TODO: implement build
    return Scaffold(
      body: getApidataList(),
    );
  }
  FutureBuilder getApidataList() {
    return FutureBuilder(
      future: ApiService.getdataList(),
      builder: (context, snapshot) {
        if (snapshot.connectionState == ConnectionState.done) {
          print("3.-Entrada (conexion establecida)");
          final data = snapshot.data;
          return ListView.separated(
            separatorBuilder: (context, index) {
              return Divider(
                height: 2,
                color: Colors.black,
              );
            },
            itemBuilder: (context, index) {
              return ListTile(
                title: Text(
                  data[index]['dataTitulo'].toString(),
                  style: TextStyle(
                      color: Colors.black, fontWeight: FontWeight.bold),
                ),
                subtitle: Text(data[index]['dataTextoBiblico'].toString()),
                onTap: () {
                  navigateToDetail(data[index]);
                },
                trailing: PopupMenuButton<dynamic>(
                    onSelected: showMenuSelection,
                    itemBuilder: (context) => [
                          PopupMenuItem(
                            child: Text("Agregar a mis listas"),
                            value: data[index],
                          )
                        ]),
              );
            },
            itemCount: data.length,
          );
        }
        return Center(
          child: CircularProgressIndicator(),
        );
      },
    );
  }


  void navigateToDetail(datadb data) async {
    bool result =
        await Navigator.push(context, MaterialPageRoute(builder: (context) {
      return dataDetalle(todo: data);
    }));
  }


  void showMenuSelection(dynamic value) async {
    bool result = await Navigator.push(
      context,
      MaterialPageRoute(
        builder: (context) => Data_List(value),
      ),
    );
    if (result) {
        SnackBar snackBar = SnackBar(
            content: Text('Se agrego correctamente a la playlist'),
        );
        _scaffoldKey.currentState.showSnackBar(snackBar);
    }
  }

  void updateListView() {
    final Future<Database> dbFuture = databaseHelper.initializeDatabase();
    dbFuture.then((databse) {
      Future<List<datadb>> dataListFuture = databaseHelper.getdataList();
      dataListFuture.then((dataList) {
        setState(() {
          this.dataList = dataList;
          this.count = dataList.length;
        });
      });
    });
  }
}

Navigator.pop(context, true);

_scaffoldKey.currentState.showSnackBar(snackBar);

NoSuchMethodError (NoSuchMethodError: The method 'showSnackBar' was called on null.
Receiver: null
Tried calling: showSnackBar(Instance of 'SnackBar'))