The argument type 'x' can't be assigned to the parameter type 'x'

Question

Below is my model class:

crm_dependent_list_model.dart (Model class)

import 'crm_dep_entitlement_model.dart';

class DependantModel{

  String name;
  String relationship;
  EntitlementsModel entitlements;

  DependantModel({this.name, this.relationship, this.entitlements});

  factory DependantModel.fromJson(Map depjson){

    return DependantModel(
      name: depjson["Name"].toString(),
      relationship: depjson["Relationship"].toString(),
      entitlements: EntitlementsModel.fromJson(depjson["Entitlements"])
    );
  }
}

This is the EntitlementsModel located inside DependantModel class

crm_dep_entitlement_model.dart

class EntitlementsModel{

  final GP gp;
  final OPS ops;
  final IP ip;
  final Dental dental;
  final Optical optical;
  final EHS ehs;

  EntitlementsModel({this.gp, this.ops, this.ip, this.dental, this.optical, this.ehs});

  factory EntitlementsModel.fromJson(Map ejson){

    return EntitlementsModel(

      gp: GP.fromJson(ejson["GP"]),
      ops: OPS.fromJson(ejson["OPS"]),
      ip: IP.fromJson(ejson["IP"]),
      dental: Dental.fromJson(ejson["Dental"]),
      optical: Optical.fromJson(ejson["Optical"]),
      ehs: EHS.fromJson(ejson["EHS"])
    );
  }

}


//GP class
class GP{

  final String entitlement, utilisation, balance;

  GP({this.entitlement, this.utilisation, this.balance});

  factory GP.fromJson(Map gjson){

    return GP(
      entitlement: gjson["Entitlement"].toString(),
      utilisation: gjson["Utilisation"].toString(),
      balance:  gjson["Balance"].toString()
    );
  }
}


//OPS class
class OPS{

  final String entitlement, utilisation, balance;

  OPS({this.entitlement, this.utilisation, this.balance});

  factory OPS.fromJson(Map gjson){

    return OPS(
        entitlement: gjson["Entitlement"].toString(),
        utilisation: gjson["Utilisation"].toString(),
        balance:  gjson["Balance"].toString()
    );
  }
}

//IP class
class IP{

  final String entitlement, utilisation, balance;

  IP({this.entitlement, this.utilisation, this.balance});

  factory IP.fromJson(Map gjson){

    return IP(
        entitlement: gjson["Entitlement"].toString(),
        utilisation: gjson["Utilisation"].toString(),
        balance:  gjson["Balance"].toString()
    );
  }
}


//Dental class
class Dental{

  final String entitlement, utilisation, balance;

  Dental({this.entitlement, this.utilisation, this.balance});

  factory Dental.fromJson(Map gjson){

    return Dental(
        entitlement: gjson["Entitlement"].toString(),
        utilisation: gjson["Utilisation"].toString(),
        balance:  gjson["Balance"].toString()
    );
  }
}


//Optical class
class Optical{

  final String entitlement, utilisation, balance;

  Optical({this.entitlement, this.utilisation, this.balance});

  factory Optical.fromJson(Map gjson){

    return Optical(
        entitlement: gjson["Entitlement"].toString(),
        utilisation: gjson["Utilisation"].toString(),
        balance:  gjson["Balance"].toString()
    );
  }
}


//EHS class
class EHS{

  final String entitlement, utilisation, balance;

  EHS({this.entitlement, this.utilisation, this.balance});

  factory EHS.fromJson(Map gjson){

    return EHS(
        entitlement: gjson["Entitlement"].toString(),
        utilisation: gjson["Utilisation"].toString(),
        balance:  gjson["Balance"].toString()
    );
  }
}

This model class is currently being used to pull data from JSON in this class:

Fifth.dart (class calling the JSON data)

import 'package:flutter/material.dart';
import 'package:emas_app/Dependant.dart' as Dep;
import 'model/crm_dependent_list_model.dart';
import 'dart:convert';
import 'dart:async';
import 'package:http/http.dart' as http;

final String url = "http://crm.emastpa.com.my/MemberInfo.json";

//Future to get list of dependent names
Future<List<DependantModel>> fetchUserInfo() async{

  http.Response response = await http.get(url);
  var responsejson = json.decode(response.body);

  return(responsejson[0]['Dependents'] as List)
      .map((user) => DependantModel.fromJson(user))
      .toList();
}

class Fifth extends StatefulWidget {
  @override
  _FifthState createState() => _FifthState();
}

class _FifthState extends State<Fifth> {

  static Future<List<DependantModel>> depState;

  @override
  void initState() {
    depState = fetchUserInfo();
    super.initState();
  }

    @override
  Widget build(BuildContext context) {

      //ListView.builder inside FutureBuilder
      var futureBuilder = new FutureBuilder(
          future: depState,
          builder: (context, snapshot){
            switch(snapshot.connectionState){
              case ConnectionState.none:
              case ConnectionState.waiting:
                return new Center(
                  child: new CircularProgressIndicator(),
                );
              default:
                if(snapshot.hasError){
                  return new Text(snapshot.error);
                }else{

                  List<DependantModel> user = snapshot.data;

                  return new ListView.builder(
                      itemCount: user.length,
                      itemBuilder: (context, index){

                        return new Column(
                          children: <Widget>[
                            new ListTile(
                              title: new Text(user[index].name,
                                  style: TextStyle(fontSize: 20.0)),
                              subtitle: new Text(user[index].relationship,
                                  style: TextStyle(fontSize: 15.0)),
                              trailing: new MaterialButton(color: Colors.greenAccent,
                                  textColor: Colors.white,
                                  child: new Text("More"),
                                  onPressed: (){
                                    Navigator.push(context,
                                        new MaterialPageRoute(builder: (context) => Dep.Dependents(name: user[index].name, entitlementsModel: user[index].entitlements))
                                    );
                                  }
                              ),
                            )
                          ],
                        );
                      });
                }
            }
          });

      return new Scaffold(
          body: futureBuilder,
      );
  }
}

The Fifth.dart class will send over data through the constructor in this class:

Dependent.dart (class with the constructor)

import 'model/crm_dep_entitlement_model.dart';
import 'package:flutter/material.dart';
import 'dart:convert';
import 'dart:async';
import 'package:http/http.dart' as http;
import 'model/crm_dependent_list_model.dart';
import 'package:flutter/foundation.dart';

final String url = "http://crm.emastpa.com.my/MemberInfo.json";

//Future method to fetch information
Future<EntitlementsModel> fetchEntitlements() async{

  final response =  await http.get(url);
  final jsonresponse = json.decode(response.body);

  var res = jsonresponse[0]["Dependents"][0]["Entitlements"];

  return EntitlementsModel.fromJson(jsonresponse[0]["Dependents"][0]["Entitlements"]);
}

//void main() => runApp(Dependents());
class Dependents extends StatefulWidget {

  final String name;
//  final Map entitlement;
  final EntitlementsModel entitlementsModel;

  //Constructor to accept the value from Fifth.dart
//  Dependents({Key key, this.name, this.dependantModel) : super(key: key);
  Dependents({Key key, this.name, this.entitlementsModel}) : super(key:key);

  @override
  _DependentsState createState() => _DependentsState();
}

class _DependentsState extends State<Dependents> {

  Future<EntitlementsModel> entitlement;

  @override
  void initState() {
    entitlement = fetchEntitlements();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {

    //new body widget
    Widget body = new Container(
      child: new Center(
        child: new FutureBuilder(
            future: entitlement,
            builder: (context, snapshot){
              if(snapshot.hasData){
                var entitledata = snapshot.data;

                //retrieve data from snapshot
                var gpentitlement = entitledata.gp.entitlement;
                var gputilisation = entitledata.gp.utilisation;
                var gpbalance = entitledata.gp.balance;

                var opsentitle = entitledata.ip.entitlement;
                var opsutilisation = entitledata.ip.utilisation;
                var opsbalance = entitledata.ip.balance;

                return new Column(
                  children: <Widget>[
                    new ListTile(
                      title: new Text("Name: "),
                      subtitle: new Text("${widget.name}"),
                    )  ,
                    new Divider(
                      color: Colors.black,
                    ),
                    new ListTile(
                      title: new Text("Clinic GP",
                        style: TextStyle(
                          fontWeight: FontWeight.bold,
                        ),
                      ),
                    ) ,
                    new ListTile(
                      title: new Text("Entitlement"),
                      trailing: new Text(gpentitlement),
                    ),
                    new ListTile(
                      title: new Text("Utilisation"),
                      trailing: new Text(gputilisation),
                    ),
                    new ListTile(
                      title: new Text("Balance"),
                      trailing: new Text(gpbalance),
                    ),
                    new Divider(
                      color: Colors.black,
                    ),
                    new ListTile(
                      title: new Text("IP",
                        style: TextStyle(
                          fontWeight: FontWeight.bold,
                        ),
                      ),
                    ),
                    new ListTile(
                      title: new Text("Entitlement"),
                      trailing: new Text(opsentitle),
                    ),
                    new ListTile(
                      title: new Text("Utilisation"),
                      trailing: new Text(opsutilisation),
                    ),
                    new ListTile(
                      title: new Text("Balance"),
                      trailing: new Text(opsbalance),
                    ),
                  ],
                );


              }else if(snapshot.hasError){
                return new Text(snapshot.error);
              }

              //loading the page
              return new Center(
                child: new CircularProgressIndicator(),
              );
            }),
      ),
    );

    return MaterialApp(
      home: Scaffold(
          appBar: AppBar(
            title: Text('${widget.name}'),
          ),
          body: body
      ),
    );
  }
}

This is the error I am running into:

compiler message: lib/Fifth.dart:72:155: Error: The argument type '#lib1::EntitlementsModel' can't be assigned to the parameter type '#lib2::EntitlementsModel'.
compiler message: Try changing the type of the parameter, or casting the argument to '#lib2::EntitlementsModel'.
compiler message:                                         new MaterialPageRoute(builder: (context) => Dep.Dependents(name: user[index].name, entitlementsModel: user[index].entitlements))
compiler message:

and also:

I/flutter ( 6816): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter ( 6816): The following assertion was thrown building FutureBuilder<List<DependantModel>>(dirty, state:
I/flutter ( 6816): _FutureBuilderState<List<DependantModel>>#bdb2c):
I/flutter ( 6816): type 'NoSuchMethodError' is not a subtype of type 'String'

My question is:

How do I fix the error because its saying I should cast the argument but I do not know how because the EntitlementsModel is a class containing multiple classes of Maps.

Solution

Seems there are conflicting imports for EntitlementsModel. Try to rewrite all your imports to be of the form:

import 'package:YOUR_PACKAGE/../...dart'

'YOUR_PACKAGE' should be the name of the application as stated in pubspec.yml name variable.

And the directory structure all the folders from the lib folder (not including it) up to the imported dart file.

(you use this import scheme in the second line of your Fifth.dart file)

Comments

[Günter Zöchbauer]

Without having a closer look at your code - please ensure you don't have relative imports in lib/main.dart and you don't import main.dart anywhere.

[Asyraf Dayan]

@GünterZöchbauer yes i already checked and I did not import main.dart anywhere.

[Günter Zöchbauer]

What about relative imports in main.dart (imports that don't start with 'dart:...' or 'package:...')

[Asyraf Dayan]

I have also tried rewriting the imports to the form you are referring to and it did not solve the problem.

[chemamolins]

Have you done that in all files, not only in Fifth.dar? When you have the error with the same type in #lib1 and #lib2, normally is because it considers the type comes from different libraries and normally the reason is using different importing mechanism.

[Asyraf Dayan]

I have managed to fix the library error. Somehow changing the package import worked after a few tries. Thanks for that.

[Asyraf Dayan]

Try taking a look at my second error that I have posted. What does it mean by FutureBuilder<List<DependantModel>>(dirty, state: I/flutter ( 6816): _FutureBuilderState<List<DependantModel>>#bdb2c): I/flutter ( 6816): type 'NoSuchMethodError' is not a subtype of type 'String'

[chemamolins]

Try to get rid of the depState static variable and use fetchUserInfo() directly in the FutureBuilder.