Issue
I am new to flutter. Am trying to consume a Rest_Api from my UI to make a get Request,however i am getting an error "Expected a value of type ‘List’, but got one of type ‘_JsonMap’",which have tried to debug based on the suggestions found online but I can’t seem to solve this issue. Here is a screenshot of the error am getting:
Here is my model and service classes:
import 'package:json_annotation/json_annotation.dart';
part 'unit.g.dart';
@JsonSerializable(explicitToJson: true)
class Unit {
String ? id;
String name;
String baseUnit;
var baseValue;
Unit({
this.id,
required this.name,
required this.baseUnit,
required this.baseValue,
});
factory Unit.fromJson(Map < String, dynamic > json) => _$UnitFromJson(json);
Map < String, dynamic > toJson() => _$UnitToJson(this);
}Future < List < Unit >> search(searchText, page) async {
var searchUrl = "${ApiEndPoint.baseUrl}/unit?q=$searchText&page=$page";
var response = await http.get(
Uri.parse(searchUrl),
headers: {
"Content-Type": "application/json"
},
);
var units = convert.json.decode(response.body) as List;
List < Unit > unitList = [];
unitList = units.map((i) => Unit.fromJson(i)).toList();
// print(unitList.length);
// print(response.body);
return unitList;
}Serialized Model Class is;
// GENERATED CODE - DO NOT MODIFY BY HAND
part of 'unit.dart';
// **************************************************************************
// JsonSerializableGenerator
// **************************************************************************
Unit _$UnitFromJson(Map < String, dynamic > json) {
return Unit(
id: json['id'] as String ? ,
name : json['name'] as String,
baseUnit: json['baseUnit'] as String,
baseValue: json['baseValue'],
);
}
Map < String, dynamic > _$UnitToJson(Unit instance) => < String, dynamic > {
'id': instance.id,
'name': instance.name,
'baseUnit': instance.baseUnit,
'baseValue': instance.baseValue,
};What could I be doing wrong?
Solution
I had to change to change the return value in the service to this and somehow it worked.
Future < List < UnitSearch >> search(searchText, page) async {
var searchUrl = "${ApiEndPoint.baseUrl}/unit?q=$searchText&page=$page";
http.Response response = await http.get(
Uri.parse(searchUrl),
headers: {
"Content-Type": "application/json"
},
);
final data = json.decode(response.body);
return List < UnitSearch > .from(
data['units'].map((item) => UnitSearch.fromJson(item)));
}Answered By – Emmon
Answer Checked By – Katrina (FlutterFixes Volunteer)