Check out example codes for "type '_InternalLinkedHashMap<DateTime, int>' is not a subtype of type 'Map<DateTime, double>'". It will help you in understanding the concepts better.

Code Example 1

Future<List<Map<String, dynamic>>> fetch() async {
  http.Response response = await http.get('http://10.0.2.2:8000/api/membres');
  if (response.statusCode != 200) return null;
  return List<Map<String, dynamic>>.from(json.decode(response.body)['membre']);
}

Learn ReactJs, React Native from akashmittal.com