how to Loop Data Json By Model

Question

i don't know flutter loop Data json http by model

{
    "messageCode": {
        "code": "00",
        "detail": "success"
    },
    "Data": [
        {
            "total_TRN_S": "552",
            "txn_TYPE": "test",
            "total_TRN_F": "25",
            "total_AMT": "2709497515"
        },
        {
            "total_TRN_S": "19",
            "txn_TYPE": "test",
            "total_TRN_F": "1",
            "total_AMT": "13348000"
        },
        {
            "total_TRN_S": "46",
            "txn_TYPE": "test",
            "total_TRN_F": "3",
            "total_AMT": "73254070"
        },
        {
            "total_TRN_S": "3",
            "txn_TYPE": "test",
            "total_TRN_F": "0",
            "total_AMT": "17270000"
        }
    ]
}

Answer 1

create related class and parse json string to object and then for loop
code snippet

String jsonStr = '{ "messageCode": { "code": "00", "detail": "success" }, "Data": [ { "total_TRN_S": "552", "txn_TYPE": "test", "total_TRN_F": "25", "total_AMT": "2709497515" }, { "total_TRN_S": "19", "txn_TYPE": "test", "total_TRN_F": "1", "total_AMT": "13348000" }, { "total_TRN_S": "46", "txn_TYPE": "test", "total_TRN_F": "3", "total_AMT": "73254070" }, { "total_TRN_S": "3", "txn_TYPE": "test", "total_TRN_F": "0", "total_AMT": "17270000" } ] }';

Payload payload = payloadFromJson(jsonStr);

for(int i=0; i< payload.data.length; i++) {
  print(' ${payload.data[i].totalTrnS} ');
}

related class

    // To parse this JSON data, do
//
//     final payload = payloadFromJson(jsonString);

import 'dart:convert';

Payload payloadFromJson(String str) => Payload.fromJson(json.decode(str));

String payloadToJson(Payload data) => json.encode(data.toJson());

class Payload {
    MessageCode messageCode;
    List<Datum> data;

    Payload({
        this.messageCode,
        this.data,
    });

    factory Payload.fromJson(Map<String, dynamic> json) => Payload(
        messageCode: MessageCode.fromJson(json["messageCode"]),
        data: List<Datum>.from(json["Data"].map((x) => Datum.fromJson(x))),
    );

    Map<String, dynamic> toJson() => {
        "messageCode": messageCode.toJson(),
        "Data": List<dynamic>.from(data.map((x) => x.toJson())),
    };
}

class Datum {
    String totalTrnS;
    String txnType;
    String totalTrnF;
    String totalAmt;

    Datum({
        this.totalTrnS,
        this.txnType,
        this.totalTrnF,
        this.totalAmt,
    });

    factory Datum.fromJson(Map<String, dynamic> json) => Datum(
        totalTrnS: json["total_TRN_S"],
        txnType: json["txn_TYPE"],
        totalTrnF: json["total_TRN_F"],
        totalAmt: json["total_AMT"],
    );

    Map<String, dynamic> toJson() => {
        "total_TRN_S": totalTrnS,
        "txn_TYPE": txnType,
        "total_TRN_F": totalTrnF,
        "total_AMT": totalAmt,
    };
}

class MessageCode {
    String code;
    String detail;

    MessageCode({
        this.code,
        this.detail,
    });

    factory MessageCode.fromJson(Map<String, dynamic> json) => MessageCode(
        code: json["code"],
        detail: json["detail"],
    );

    Map<String, dynamic> toJson() => {
        "code": code,
        "detail": detail,
    };
}

full code

import 'package:flutter/material.dart';

// To parse this JSON data, do
//
//     final payload = payloadFromJson(jsonString);

import 'dart:convert';

Payload payloadFromJson(String str) => Payload.fromJson(json.decode(str));

String payloadToJson(Payload data) => json.encode(data.toJson());

class Payload {
  MessageCode messageCode;
  List<Datum> data;

  Payload({
    this.messageCode,
    this.data,
  });

  factory Payload.fromJson(Map<String, dynamic> json) => Payload(
    messageCode: MessageCode.fromJson(json["messageCode"]),
    data: List<Datum>.from(json["Data"].map((x) => Datum.fromJson(x))),
  );

  Map<String, dynamic> toJson() => {
    "messageCode": messageCode.toJson(),
    "Data": List<dynamic>.from(data.map((x) => x.toJson())),
  };
}

class Datum {
  String totalTrnS;
  String txnType;
  String totalTrnF;
  String totalAmt;

  Datum({
    this.totalTrnS,
    this.txnType,
    this.totalTrnF,
    this.totalAmt,
  });

  factory Datum.fromJson(Map<String, dynamic> json) => Datum(
    totalTrnS: json["total_TRN_S"],
    txnType: json["txn_TYPE"],
    totalTrnF: json["total_TRN_F"],
    totalAmt: json["total_AMT"],
  );

  Map<String, dynamic> toJson() => {
    "total_TRN_S": totalTrnS,
    "txn_TYPE": txnType,
    "total_TRN_F": totalTrnF,
    "total_AMT": totalAmt,
  };
}

class MessageCode {
  String code;
  String detail;

  MessageCode({
    this.code,
    this.detail,
  });

  factory MessageCode.fromJson(Map<String, dynamic> json) => MessageCode(
    code: json["code"],
    detail: json["detail"],
  );

  Map<String, dynamic> toJson() => {
    "code": code,
    "detail": detail,
  };
}


void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  String jsonStr = '{ "messageCode": { "code": "00", "detail": "success" }, "Data": [ { "total_TRN_S": "552", "txn_TYPE": "test", "total_TRN_F": "25", "total_AMT": "2709497515" }, { "total_TRN_S": "19", "txn_TYPE": "test", "total_TRN_F": "1", "total_AMT": "13348000" }, { "total_TRN_S": "46", "txn_TYPE": "test", "total_TRN_F": "3", "total_AMT": "73254070" }, { "total_TRN_S": "3", "txn_TYPE": "test", "total_TRN_F": "0", "total_AMT": "17270000" } ] }';
  void _incrementCounter() {
    Payload payload = payloadFromJson(jsonStr);

    for(int i=0; i< payload.data.length; i++) {
      print(' ${payload.data[i].totalTrnS} ');
    }
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

demo print result