I am new to Flutter, I need help to understand how to format my request payload for a parameter containing a list of items in Flutter.

Parameter: "receiverListRequest"

Sample Request Payload:

{
    "id": "abcd12234555",
    "amount": "100",
    "receiverCount": "2",
    "receiverListRequest": [
        {
          
            "phone": "9123456",
            "id": "abcd12234555",
            "name": "Mark",
            "amount": "100"
        },
         {
           
            "phone": "9123456",
            "id": "abcd12234555",
            "name": "Robert",
            "amount": "520"
        }
                
    ]
}

I could reach until this step, and stuck now, as no idea how to format my data:

  Future<SubmitDataModel> submitData(
        {id,
        amount,
        receiverCount,
        required Map<String, dynamic> receiverReqList}) async {
    response = await dio.post(
        'my_submit_URL',
        data: {
          'id': '$id',
          'amount': '$amount',
          'receiverCount': '$receiverCount',
          'receiverListRequest': receiverReqList
        }).then((value) {
      if (value.statusCode == 200) {
        response = value;
        return SubmitDataModel.fromJson(response.data);
      } 
    });
    log('$response');
    return SubmitDataModel.fromJson(response.data);
}

I am stuck here.

APIFunctions _apiCaller = APIFunctions();

    _apiCaller
              .submitRequest(
                "id": "abcd12234555",
                "amount": "100",
                "receiverCount": "2",
                "receiverListRequest": (// ***How to Add my list of data here??***))
                    .then((value) {
            if (value.status == 200) {
             // to do something here
            }
          });

CodePudding user response：

You can create a list inside the model class

Say, Your responce is also giving a list inside the json create a list variable inside the model class. In your case :-

String id;
String amount;
String receiverCount;
List<ReceiverListRequest> receiverListRequest;

Inside the factory method whenever you refer to the list variable call for a new method (or class) where you will be casting these list values to a new class.

in your case : - receiverListRequest: List<ReceiverListRequest>.from(json["receiverListRequest"].map((x) => ReceiverListRequest.fromJson(x))),

your ReceiverListRequest Model class will look like this: -

class ReceiverListRequest {
    ReceiverListRequest({
        this.phone,
        this.id,
        this.name,
        this.amount,
    });

    String phone;
    String id;
    String name;
    String amount;
}

Inside that class you also have an other factor method to cast the dynamic string responce to a Map like what you have done before.

Something like this:-

  factory ReceiverListRequest.fromJson(Map<String, dynamic> json) => ReceiverListRequest(
        phone: json["phone"],
        id: json["id"],
        name: json["name"],
        amount: json["amount"],
    );

    Map<String, dynamic> toJson() => {
        "phone": phone,
        "id": id,
        "name": name,
        "amount": amount,
    };
}

Your full dart class for your JSON responce will look like this

// To parse this JSON data, do
//
//     final listRequest = listRequestFromJson(jsonString);

import 'dart:convert';

ListRequest listRequestFromJson(String str) => ListRequest.fromJson(json.decode(str));

String listRequestToJson(ListRequest data) => json.encode(data.toJson());

class ListRequest {
    ListRequest({
        this.id,
        this.amount,
        this.receiverCount,
        this.receiverListRequest,
    });

    String id;
    String amount;
    String receiverCount;
    List<ReceiverListRequest> receiverListRequest;

    factory ListRequest.fromJson(Map<String, dynamic> json) => ListRequest(
        id: json["id"],
        amount: json["amount"],
        receiverCount: json["receiverCount"],
        receiverListRequest: List<ReceiverListRequest>.from(json["receiverListRequest"].map((x) => ReceiverListRequest.fromJson(x))),
    );

    Map<String, dynamic> toJson() => {
        "id": id,
        "amount": amount,
        "receiverCount": receiverCount,
        "receiverListRequest": List<dynamic>.from(receiverListRequest.map((x) => x.toJson())),
    };
}

class ReceiverListRequest {
    ReceiverListRequest({
        this.phone,
        this.id,
        this.name,
        this.amount,
    });

    String phone;
    String id;
    String name;
    String amount;

    factory ReceiverListRequest.fromJson(Map<String, dynamic> json) => ReceiverListRequest(
        phone: json["phone"],
        id: json["id"],
        name: json["name"],
        amount: json["amount"],
    );

    Map<String, dynamic> toJson() => {
        "phone": phone,
        "id": id,
        "name": name,
        "amount": amount,
    };
}