Flutter data serialization and deserialization with firestore db - flutter

Question

I ran into this weird error in Flutter. I'm using a custom data model:
class ScanData {
final String userID;
final String companyID;
final String scanID;
final String deviceID;
final String model;
final Map result;
final DateTime dateTime;
final GeoPoint geoPoint;
ScanData(
{this.userID,
this.companyID,
this.scanID,
this.deviceID,
this.model,
this.result,
this.geoPoint,
this.dateTime});
factory ScanData.fromMap(Map data) {
return ScanData(
userID: data['userID'] ?? '',
companyID: data['companyID'] ?? '',
scanID: data['scanID'] ?? '',
deviceID: data['deviceID'] ?? '',
model: data['model'] ?? '',
result: data['result'] ?? {},
dateTime: data['dateTime'] as DateTime ?? DateTime.now(),
geoPoint: data['geoPoint'] as GeoPoint ?? ['77', '28'],
);
}
}
Created a method in Collection class to retrieve data from firestore:
class Collection<T> {
final FirebaseFirestore _db = FirebaseFirestore.instance;
final String path;
CollectionReference ref;
Collection({this.path}) {
ref = _db.collection(path);
}
Future<List<T>> getData() async {
var snapshots = await ref.get();
return snapshots.docs
.map((doc) => Global.models[T](doc.data) as T)
.toList();
}
}
Calling it in widget, this works if I don't use the data model and instead call the collection directly, but it's much easier since I don't want to create it everywhere I go and helps with type checking and intellisense...
FutureBuilder(
future: Collection<ScanData>(path: 'scans').getData(),
builder: (context, AsyncSnapshot<List<ScanData>> snapshot) {
if (!snapshot.hasData || snapshot.hasError) {
return Container(
alignment: Alignment.center,
child: CircularProgressIndicator());
} else {
return _buildScansList(snapshot.data);
}
},
)
Globals:
class Global {
static final Map models = {
ScanData: (data) => ScanData.fromMap(data),
};
}
The error (occurs in Globals fromMap):
Exception has occurred.
_TypeError (type '() => Map<String, dynamic>' is not a subtype of type 'Map<dynamic, dynamic>')
I tried putting the following in the ScanData model
factory ScanData.fromMap(Map<String,dynamic> data) {...}
but this gives another error:
Exception has occurred.
_TypeError (type '() => Map<String, dynamic>' is not a subtype of type 'Map<String, dynamic>')
:| Any tips appreciated.

Answer 1

In the method getData() of Collection class, doc.data is not property, it's a method, so just add ().