Flutter : Mongo Dart Plugin is not working - dart

Question

i want to use mongo to store my app data, but when ever i try to await db.open() this error appear on the console:
[ERROR:topaz/lib/tonic/logging/dart_error.cc(16)] Unhandled exception:
E/flutter (11408): type 'Future<dynamic>' is not a subtype of type 'Future<bool>' where
E/flutter (11408): Future is from dart:async
E/flutter (11408): Future is from dart:async
E/flutter (11408): bool is from dart:core
E/flutter (11408):
E/flutter (11408): #0 _Connection.connect (file:///C:/Users/Picmix/flutter/.pub-cache/hosted/pub.dartlang.org/mongo_dart-0.3.1/lib/src/network/connection.dart:73:22)
E/flutter (11408): #1 _ConnectionManager._connect (file:///C:/Users/Picmix/flutter/.pub-cache/hosted/pub.dartlang.org/mongo_dart-0.3.1/lib/src/network/connection_manager.dart:23:22)
E/flutter (11408): <asynchronous suspension>
E/flutter (11408): #2 _ConnectionManager.open.<anonymous closure> (file:///C:/Users/Picmix/flutter/.pub-cache/hosted/pub.dartlang.org/mongo_dart-0.3.1/lib/src/network/connection_manager.dart:58:14)
E/flutter (11408): #3 Future.forEach.<anonymous closure> (dart:async/future.dart:484:26)
E/flutter (11408): #4 Future.doWhile.<anonymous closure> (dart:async/future.dart:526:26)
E/flutter (11408): #5 _RootZone.runUnaryGuarded (dart:async/zone.dart:1316:10)
E/flutter (11408): #6 _RootZone.bindUnaryCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1355:26)
E/flutter (11408): #7 Future.doWhile (dart:async/future.dart:541:18)
E/flutter (11408): #8 Future.forEach (dart:async/future.dart:482:12)
E/flutter (11408): #9 _ConnectionManager.open (file:///C:/Users/Picmix/flutter/.pub-cache/hosted/pub.dartlang.org/mongo_dart-0.3.1/lib/src/network/connection_manager.dart:56:19)
E/flutter (11408): #10 Db.open.<anonymous closure> (file:///C:/Users/Picmix/flutter/.pub-cache/hosted/pub.dartlang.org/mongo_dart-0.3.1/lib/src/database/db.dart:252:33)
E/flutter (11408): #11 new Future.sync (dart:async/future.dart:222:31)
E/flutter (11408): #12 Db.open (file:///C:/Users/Picmix/flutter/.pub-cache/hosted/pub.dartlang.org/mongo_dart-0.3.1/lib/src/database/db.dart:239:16)
E/flutter (11408): #13 main (file:///F:/Jamil/WORKSHOP/MY-PRACTICE/FLUTTER/FLUTTERMONGO/simplecrud/lib/main.dart:6:6)
E/flutter (11408): <asynchronous suspension>
E/flutter (11408): #14 _startIsolate.<anonymous closure> (dart:isolate/runtime/libisolate_patch.dart:279:19)
E/flutter (11408): #15 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:165:12)
E/flutter (11408): [ERROR:topaz/lib/tonic/logging/dart_error.cc(16)] Unhandled exception:
E/flutter (11408): type '(MongoReplyMessage) => void' is not a subtype of type '(dynamic) => void'
E/flutter (11408): #0 _rootHandleUncaughtError.<anonymous closure> (dart:async/zone.dart:1114:29)
E/flutter (11408): #1 _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
E/flutter (11408): #2 _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)
and this is the simple code that i write to open connection between mlab and the app:
import 'package:mongo_dart/mongo_dart.dart';
void main() async {
print('hello');
Db db = new Db('mongodb://<myusername><mypassword>#ds147659.mlab.com:47659/simple-crud');
db.open().then((success) {
if (success) print('connected');
});
}
any idea sir?

Answer 1

This is due to the latest flutter update beta2.
Please check this blog by flutter
Seems like there is a flutter version mismatch of your project and Mongo plugin.
Mongo's latest plugin was updated on Oct 24, 2017.
There is already an issue on their git. You can keep track of it.
Meanwhile, according to this issue:
you can try changing the plugin code from
Future<bool> get isOn => _channel.invokeMethod('isOn');
to
Future<bool> get isOn async {
final bool isOn = await _channel.invokeMethod('isOn');
return isOn;
}
NOTE: Above is just an example, please check the plugin dart file for the correct function to change.