Snapshot from StreamBuilder - flutter

Question

I am working on a ListView inside a Streambuilder with data from Cloud Firestore.
Here you have the code:
//inicio stream
StreamBuilder<List<Evento>>(
stream: eventosProvider
.eventosbares,
builder: (context, snapshot) {
if (snapshot
.data.isNotEmpty) {
return SizedBox(
height: 155,
child: ListView.builder(
scrollDirection:
Axis.horizontal,
itemCount: snapshot
.data.length,
itemBuilder:
(context,
index) {
var dateString =
snapshot
.data[
index]
.fechaEvento;
var date = DateFormat(
'd-M-yyyy HH:mm',
'de_DE')
.parse(
dateString);
return Card(
shape:
RoundedRectangleBorder(
borderRadius:
BorderRadius
.circular(
10),
),
child:
Container(
height: 178,
width: 280,
child: Column(
children: [
Padding(
padding: const EdgeInsets.only(
left: 8.0,
right: 8.0,
top: 8.0),
child:
ClipRRect(
borderRadius:
BorderRadius.circular(8),
child:
Image.network(
snapshot.data[index].imagenEvento,
width: 278.0,
height: 80.0,
fit: BoxFit.fill,
),
),
),
Padding(
padding:
const EdgeInsets.all(8.0),
child:
Row(
mainAxisAlignment:
MainAxisAlignment.start,
children: [
CircleAvatar(
radius: 20.0,
backgroundImage: NetworkImage(snapshot.data[index].fotoPerfilAutor),
backgroundColor: Colors.transparent,
),
Padding(
padding: const EdgeInsets.all(2.0),
child: Container(
width: 150,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
snapshot.data[index].tituloEvento,
overflow: TextOverflow.ellipsis,
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 13,
),
),
Text(
DateFormat('EEEEE dd MMM yyyy HH:mm', 'es_ES').format(date),
style: TextStyle(fontSize: 10),
),
],
),
),
),
SizedBox(
width: 10,
),
Text(
snapshot.data[index].num_invitados,
style: TextStyle(color: ColoresApp.naranjaTop, fontWeight: FontWeight.bold, fontSize: 14),
),
SizedBox(
width: 5,
),
CircleAvatar(
radius: 10.0,
backgroundImage: AssetImage("assets/friends.png"),
backgroundColor: Colors.transparent,
)
],
),
),
]),
),
);
}),
);
} else {
return Text(
"No hay eventos en bares",
style: TextStyle(
color:
Colors.white),
);
}
}),
I am getting the following exception using this code, the app is not exiting, it only shows a red error background for a moment, but it is not acceptable:
======== Exception caught by widgets library =======================================================
The following NoSuchMethodError was thrown building StreamBuilder<List<Evento>>(dirty, state: _StreamBuilderBaseState<List<Evento>, AsyncSnapshot<List<Evento>>>#d6fd3):
The getter 'isNotEmpty' was called on null.
Receiver: null
Tried calling: isNotEmpty
I have tried changing the line:
if (snapshot.data.isNotEmpty)
with
if (snaphot.hasData)
but then, the exception is gone, but there is a blank space thrown, not the else part of the if clause.
What should I do to know if the snapshop has really data or is waiting to get them?
EDIT
Here you have the service loading the Stream:
Stream<List<Evento>> getEventosBares(){
return _db
.collection('eventos').where('interes', isEqualTo: 'bares')
.snapshots()
.map((snapshot) => snapshot.docs
.map((doc) => Evento.fromJson(doc.data()))
.toList());
}
And here you have the provider:
Stream<List<Evento>> get eventosbares => firestoreService.getEventosBares();

Answer 1

Try adding a null check:
builder: (context, snapshot) {
if (snapshot.data != null && snapshot.data.isNotEmpty) {
return SizedBox(...);