How to pass data between isolates in flutter dart - flutter

Question

I am buiding an app were I want to run a batch operation in firestore and I want to run it in a different isolate. Here is my code for spawning the isolate:
Future<void> _startAnotherIsolate(String mediaUrl) async {
final isolate = await FlutterIsolate.spawn(isolate1,"hello"); // i need to pass 2 more
arguments
Timer(Duration(seconds: 5), () {
print("Pausing Isolate 1");
isolate.pause();
});
Timer(Duration(seconds: 10), () {
print("Resuming Isolate 1");
isolate.resume();
});
Timer(Duration(seconds: 20), () {
print("Killing Isolate 1");
isolate.kill();
});
}
My code for the isolate:
void isolate1(String data1, String data2) async {
await Firebase.initializeApp();
print("changing profile picture: $phone");
Timer.periodic(Duration(seconds: 1), (timer) => print("Timer Running From Isolate 1"));
var db = FirebaseFirestore.instance;
var batch = db.batch();
FirebaseFirestore.instance.collection("posts").doc(phone).collection("userPosts")
.get().then((querySnapshot) {
for (var document in querySnapshot.docs) {
try {
batch.update(document.reference,{'user_image': mediaUrl});
} on FormatException catch (error) {
// If a document ID is unparsable. Example "lRt931gu83iukSSLwyei" is unparsable.
// print("The document ${error.source} could not be parsed.");
return null;
}
}
return batch.commit();
});
}
I have seen This link and this link but they are not helpful

Answer 1

import 'dart:isolate';
class RequiredArgs {
late final SendPort sendPort;
late int id;
RequiredArgs(this.id, this.sendPort);
}
Future<void> main() async {
ReceivePort receivePort = ReceivePort();
RequiredArgs requiredArgs = RequiredArgs(1122, receivePort.sendPort);
Isolate isolate = await Isolate.spawn(download, requiredArgs);
var resp = await receivePort.first;
print(resp);
}
void download(RequiredArgs requiredArgs) {
final SendPort sendPort = requiredArgs.sendPort;
final id = requiredArgs.id;
print(id);
sendPort.send("yes");
}
We pass the value using the RequiredArgs class. Hope my answer helps.