Invalid argument(s): Illegal argument in isolate message : (object is a closure - Function 'createDataList':.) - flutter

Question

I tried to fetch data from the internet with moviedb API, I followed the tutorial at https://flutter.io/cookbook/networking/fetch-data/
but I'm getting the below error.
Invalid argument(s): Illegal argument in isolate message : (object is a closure - Function 'createDataList':.)
This my code
Future<List<DataModel>> fetchData() async{
final response = await http.get("https://api.themoviedb.org/3/movie/now_playing?api_key=d81172160acd9daaf6e477f2b306e423&language=en-US");
if(response.statusCode == 200){
return compute(createDataList,response.body.toString());
}
}
List<DataModel> createDataList(String responFroJson) {
final parse = json.decode(responFroJson).cast<Map<String, dynamic>>();
return parse.map<DataModel> ((json) => DataModel.fromtJson(json)).toList();
}
Screenshot of the error message

Answer 1

compute can only take a top-level function, but not instance or static methods.
Top-level functions are functions declared not inside a class
and not inside another function
List<DataModel> createDataList(String responFroJson) {
...
}
class SomeClass { ... }
should fix it.
https://docs.flutter.io/flutter/foundation/compute.html
R is the type of the value returned. The callback argument must be a top-level function, not a closure or an instance or static method of a class.

Answer 2

As per today (2020. Aug) the compute is working fine with static methods.
For me, the issue was that I was trying to return a http.Response object from the compute() methods.
What I did is I've created a simplified version of this class, containing what I need:
class SimpleHttpResponse {
String body;
int statusCode;
Map<String, String> headers;
}
Then I've updated the original method from this:
static Future<http.Response> _executePostRequest(EsBridge bridge) async {
return await http.post(Settings.bridgeUrl, body: bridge.toEncryptedMessage());
}
to this:
static Future<SimpleHttpResponse> _executePostRequest(EsBridge bridge) async {
http.Response result = await http.post(Settings.bridgeUrl, body: bridge.toEncryptedMessage());
if (result == null) {
return null;
}
SimpleHttpResponse shr = new SimpleHttpResponse();
shr.body = result.body;
shr.headers = result.headers;
shr.statusCode = result.statusCode;
return shr;
}
Worked like charm after this change. Hope this helps somebody ranning into similar problem.