Present placeholder when there is no data in collection - flutter

Question

I'm trying to display a Text widget when the collection is empty. However I never can meet the condition to display Text('No Events :('); even when my collection is empty. I presume it's a dart syntax error?
Container(
height: 400,
// width: 500,
child: StreamBuilder<QuerySnapshot>(
stream: Firestore.instance.collection('Events').where("bandId", isEqualTo:identifier ).snapshots(),
builder: (BuildContext context,
AsyncSnapshot<QuerySnapshot> snapshot) {
if (!snapshot.hasData)
return new Text('No Events :(');
switch (snapshot.connectionState) {
case ConnectionState.waiting:
return new Text('Loading...');
default:
return new ListView(
children: snapshot.data.documents
.map((DocumentSnapshot document) {
return Dismissible(
key: new Key(document.documentID),
onDismissed: (direction){
Firestore.instance.runTransaction((transaction) async {
DocumentSnapshot snapshot=
await transaction.get(document.reference);
await transaction.delete(snapshot.reference);
});
Fluttertoast.showToast(msg: "Event Deleted");
},
child: CustomCard(
event: document['event'],
location: document['location'],
service: document['service'],
date: document['date'],
),
);
}).toList(),
);
}
},
)),

Answer 1

You are creating a syntax error.
You can not use
new Text("Something");
new ListView(
//
)
You have to specify a Widget which support Children.
You can use Column for displaying multiple Widgets.
Reason: You are specifying If and Switch case.
I would suggest cover your logic inside Switch case only or in If-Else condition.
Container(
height: 400,
// width: 500,
child: StreamBuilder(
stream: Firestore.instance.collection('Events').where("bandId", isEqualTo:identifier ).snapshots(),
builder: (BuildContext context,
AsyncSnapshot snapshot) {
return new Column(
children: [
if (!snapshot.hasData)
new Text('No Events :('),
switch (snapshot.connectionState) {
case ConnectionState.waiting:
new Text('Loading...');
default:
new Container(
childe: ListView(
children: snapshot.data.documents
.map((DocumentSnapshot document) {
return Dismissible(
key: new Key(document.documentID),
onDismissed: (direction){
Firestore.instance.runTransaction((transaction) async {
DocumentSnapshot snapshot=
await transaction.get(document.reference);
await transaction.delete(snapshot.reference);
});
Fluttertoast.showToast(msg: "Event Deleted");
},
child: CustomCard(
event: document['event'],
location: document['location'],
service: document['service'],
date: document['date'],
),
);
}).toList(),
),
),
}
]),
},
)
);