How to read from an ID list in Firebase? - flutter

Question

I have a list of IDs (Future<List<String>> _listaIdEmpresasF) and I would like to query data based on each ID in the list. I'm using two FutureBuilders: The first one to get the list of IDs, and the second one to display the data related of each ID.
My code looks like this...
#override
void initState() {
super.initState();
_listaIdEmpresasF = _usuarioBloc.cargarEmpresasDeUsuario(_prefs.idUsuario);
}
Widget _crearListado(BuildContext context) {
return FutureBuilder(
future: _listaIdEmpresasF,
builder: (BuildContext context, AsyncSnapshot snapshot) {
print(snapshot.connectionState);
if (snapshot.connectionState == ConnectionState.done && snapshot.hasData != null){
final List<String> _listaIdEmpresas = snapshot.data;
return FutureBuilder(
future: _empresaDatosBloc.cargarEmpresaDatosListado(_listaIdEmpresas),
builder: (BuildContext context, AsyncSnapshot snapshot2) {
print(snapshot2.connectionState);
if (snapshot2.connectionState == ConnectionState.done && snapshot2.hasdata) {
final List<EmpresaDatosModel> _listaEmpresas = snapshot2.data;
return Stack(
children: <Widget>[
ListView.builder(
itemCount: _listaEmpresas.length,
itemBuilder: (context, i) {
return _crearItem(context, _listaEmpresas[i], i);
},
padding: EdgeInsets.only(left: 10.0, right: 10.0, top: 0.0, bottom: 20.0),
),
],
);
} else return Align(
alignment: Alignment.center,
child: Center (child: Image(image: AssetImage('Preloader.gif'), height: 500.0,)),
);
},
);
}
else return Align(
alignment: Alignment.center,
child: Center (child: Image(image: AssetImage('Preloader.gif'), height: 500.0,)),
);
},
);
}
To get the data from each ID, I'm using a loop as follows:
Future<List<EmpresaDatosModel>> cargarEmpresaDatosListado(List<String> listaIdEmpresas) async {
final List<EmpresaDatosModel> listaEmpresas = new List();
listaIdEmpresas.forEach((id) async {
Query resp = db.child('empresas/$id/datos');
final snapshot = await resp.once();
if (snapshot.value == null) return [];
final temp = EmpresaDatosModel.fromJson(Map<String,dynamic>.from(snapshot.value));
temp.idEmpresa = id;
listaEmpresas.add(temp);
print('${temp.nombre} subida');
await resp.once().then((snapshot) {
print("Los Datos de una Empresa se cargaron totalmente - ${temp.nombre}");
});
});
listaEmpresas.forEach((element) {print('Emp ${element.nombre}');});
return listaEmpresas;
}
The problem: I can't be able to obtain the full data. For example, if I have three IDs in _listaIdEmpresas, sometimes the app displays a list of one company (related to the first ID), sometimes two companies (first and secod ID) and sometimes the three companies. I supposed this is because the ConnectionState of the second snapshot is done before reading all three loops..
I tried to add a condition but it didn't work...
if (snapshot2.connectionState == ConnectionState.done && snapshot2.data.length == _listaIdEmpresas.length)
I cannot query all companies and filter it as a list of companies due to query security rules that I configured.
I would like to include the specific list of IDs in the query parameters, but I don't know if it's possible.
How is the right way to read data from a list of IDs?

Answer 1

snapshot.key will give you the id of the item