How to parse a document from my Firestore Database - dart

Question

How can I parse the data from my Firestore. My Document looks like:
with this code, I get my data.
StreamBuilder(
stream: Firestore.instance.collection("Benutzer").document("Anton").collection("Einkaufsliste").snapshots(),
builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot){
return ListView.builder(
itemCount: snapshot.data.documents.length,
itemBuilder: (context, index){
return ExpansionTile(
title: Text(snapshot.data.documents[index].documentID),
children: buildCheckBoxListTile(index, snapshot),
in the buildCheckBoxListTile(index, snapshot) Function I wanted to get the data from the maps. So, how can I parse these Data?
Thank you for help.
Edit:
I created a class Produkte:
class Produkte{
Produkte({this.produktList});
List<Produkt> produktList;
factory Produkte.fromJson(Map<String, dynamic> parsedJson){
var list = parsedJson["Produkte"] as List;
List<Produkt> products = list.map((i) => Produkt.fromJson(i)).toList();
return Produkte(
produktList: products,
);
}
}
And a class Produkt:
class Produkt{
Produkt({this.name, this.anzahl});
String name;
int anzahl;
factory Produkt.fromJson(Map<String, dynamic> parsedJson){
return Produkt(
name: parsedJson["Name"],
anzahl: parsedJson["Anzahl"]
);
}
}
Now when i call this: Produkte Hans = Produkte.fromJson(snapshot.data.documents[index].data);
the follwoing Exception is thrown:
I/flutter (18038): Another exception was thrown: type '_InternalLinkedHashMap<dynamic, dynamic>' is not a subtype of type 'Map<String, dynamic>'

Answer 1

i had the same issue. I am using the json_serializable package for automatic generation.
For me it helped, to remove the cast types from the map
factory Produkt.fromJson(Map parsedJson)
and allowed any map on the annoation
#JsonSerializable(anyMap: true)
There was an issue with some discussion over this topic in the flutter repository. HerrNiklasRaab posted a other workaround there as well:
factory Chat.fromJson(Map<String, dynamic> json) {
json["members"] = (json['members'] as List)
?.map((e) =>
e == null ? null : Map<String, dynamic>.from(e))
?.toList();
return _$ChatFromJson(json);
}