Flutter compare num with dynamic from Firebase - firebase

Question

I want to compare the App's version manually through Firebase Firestore. In Firestore, I have a collection(system) with a document(update) with a field: newest_v_app = number 7. I want to access this field on a page in my app and want to compare it to a number. If the number in firestore is higher than the number in the app, I want a bool to set to true.
The Code I tried (to explain what I mean):
UpdatePage.dart
class UpdatePage extends StatefulWidget {
#override
_UpdatePageState createState() => _UpdatePageState();
}
class _UpdatePageState extends State<UpdatePage> {
bool update_available = false;
num current_version = 7;
dynamic newest_version_from_firebase = 7;
Future<dynamic> _getUpdateAvailable() async {
final DocumentReference document = FirebaseFirestore.instance.collection('system').doc('update');
print('Success GetUpdate 1');
await document.get().then<dynamic>((DocumentSnapshot snapshot) async {
setState(() {
newest_version_from_firebase = snapshot.data;
});
});
print('Success GetUpdate 2');
compareUpdate(context);
print('Success GetUpdate 3');
testUpdateComparer();
}
void compareUpdate(BuildContext context) {
if (newest_version_from_firebase > current_version) {
setState(() {
update_available = true;
});
} else {
setState(() {
update_available = false;
});
}
}
void testUpdateComparer() {
if (update_available == true) {
print('Success AvailableBool');
} else {
print('No AvailableBool');
}
}
#override
void initState() {
super.initState();
print('Success Init');
_getUpdateAvailable();
}
#override
Widget build(BuildContext context) {
Size size = MediaQuery.of(context).size;
SystemChrome.setPreferredOrientations([
DeviceOrientation.portraitUp,
]);
return Scaffold(
);
}
}
Console & Error:
I/flutter (15814): Success Init
I/flutter (15814): Success GetUpdate 1
W/DynamiteModule(15814): Local module descriptor class for providerinstaller not found.
I/DynamiteModule(15814): Considering local module providerinstaller:0 and remote module providerinstaller:0
W/ProviderInstaller(15814): Failed to load providerinstaller module: No acceptable module found. Local version is 0 and remote version is 0.
I/flutter (15814): Success GetUpdate 2
I/flutter (15814): No AvailableBool
E/flutter (15814): [ERROR:flutter/lib/ui/ui_dart_state.cc(213)] Unhandled Exception: NoSuchMethodError: Closure call with mismatched arguments: function '>'
E/flutter (15814): Receiver: Closure: () => Map<String, dynamic>? from Function 'data':.
E/flutter (15814): Tried calling: >(7)
E/flutter (15814): Found: >() => Map<String, dynamic>?
E/flutter (15814): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:63:5)
E/flutter (15814): #1 _UpdatePageState.compareUpdate (package:myapp/UpdatePage/UpdatePage.dart:44:38)
E/flutter (15814): #2 _UpdatePageState._getUpdateAvailable (package:myapp/UpdatePage/UpdatePage.dart:38:5)
E/flutter (15814): <asynchronous suspension>
E/flutter (15814):
Flutter 2.3.0-17.0.pre.19 • channel master • https://github.com/flutter/flutter.git
Framework • revision bcf05f4587 (4 months ago) • 2021-05-23 02:19:02 -0400
Engine • revision 8cd4cf0a67
Tools • Dart 2.14.0 (build 2.14.0-143.0.dev)

Answer 1

The snapshot.data returns a Map<String, dynamic> from firestore and you're trying to assign it to the variable newest_version_from_firebase that you're trying to use as a number, which is not possible.
snaposhot.data returns a Document in which your have your version number probably stored as a key value pair, like: {"versionNumber": 7}
to access it your should do, for example:
newest_version_from_firebase = snapshot.data["versionNumber"] as int;

Answer 2

Solved it:
Changed num to int
late DocumentSnapshot snapshot;
int current_version = 7;
int newest_version_from_firebase = 7;
void getUpdateAvailable() async {
final data = await FirebaseFirestore.instance.collection("system").doc("update").get() as DocumentSnapshot;
snapshot = data as DocumentSnapshot;
setState(() {
newest_version_from_firebase = snapshot["newest_version"] as int;
});
print(newest_version_from_firebase.toString());
compareUpdate(context);
}