FutureBuilder shows [instance] instead of actual data - flutter

Question

I want to download a list from firestore and display as a list in flutter widget. The data is successfully downloaded (proved by the print(cp.data()).
However, the result shown is [Instance of '_JsonQueryDocumentSnapshot'] instead of the actual carpark data.
Could anyone pls help point out what the bug is.
Thanks
class DownloadDataScreen extends StatefulWidget {
#override
_DownloadDataScreen createState() => _DownloadDataScreen();
}
class _DownloadDataScreen extends State<DownloadDataScreen> {
List<DocumentSnapshot> carparkList = []; //List for storing carparks
void initState() {
super.initState();
readFromFirebase();
}
Future readFromFirebase() async {
// await FirebaseFirestore.instance
await FirebaseFirestore.instance
.collection('carpark')
.get()
.then((QuerySnapshot snapshot) {
snapshot.docs.forEach(
(DocumentSnapshot cp) {
carparkList.add(cp);
print('printing cp');
print(cp.data());
},
);
});
**return carparkList;**
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: new AppBar(
title: new Text(
'Car Park',
style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
),
centerTitle: true,
),
body: FutureBuilder(
future: readFromFirebase(),
builder: (BuildContext context, AsyncSnapshot snapshot) {
List<Widget> children;
if (snapshot.hasData) {
children = <Widget>[
const Icon(
Icons.check_circle_outline,
color: Colors.green,
size: 60,
),
Padding(
padding: const EdgeInsets.only(top: 16),
child: Column(
children: [
Text('Result: ${snapshot.data}'),
],
),
)
];
} else if (snapshot.hasError) {
children = <Widget>[
const Icon(
Icons.error_outline,
color: Colors.red,
size: 60,
),
Padding(
padding: const EdgeInsets.only(top: 16),
child: Text('Error: ${snapshot.error}'),
)
];
} else {
children = const <Widget>[
SizedBox(
child: CircularProgressIndicator(),
width: 60,
height: 60,
),
Padding(
padding: EdgeInsets.only(top: 16),
child: Text('Awaiting result...'),
)
];
}
return Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: children,
),
);
},
),
);
}
}

Answer 1

First, you don't need to call the function from the init because you already use the FutureBuilder.
Also, you don't need to cast it because when the future completes, the async snapshot already would provide you a list of DocumentSnapshot in the data and the .doc propertie.
Like this:
FutureBuilder<QuerySnapshot>(
builder:(context,snapshot){
if(snapshot.hasData){
/// here your data
snapshot.data.docs;
}
)