Flutter Dart Parsing Json Strings into Objects

Question

Sup, So my problem is. my Dashboard Model isnt getting data assigned from the json string parsed.Basically Dashboard.userActivity and Dashboard.appName are NULL when i print into console. I cant realy get behind why, the testDataFunction should print the corresponding Dashboard Object with all their data (2 nested classes Performance and UserActivity and 3 variables errors, appname.time. I did not include the code of Perf and UserAct. as its the same as Dashboard with toJson and fromJson helper Methods.

What did i oversaw? Much thanks in advance!

import 'dart:convert';
import 'package:flutter/foundation.dart';
import 'package:font_awesome_flutter/font_awesome_flutter.dart';


class Dashboard {

  UserActivity? userActivity; ///class
  int? totalError;
  Performance? performance;  ///class
  String? appName;
  String? time;

  Dashboard(
      {this.userActivity,
        this.totalError,
        this.performance,
        this.appName,
        this.time});
  

  Dashboard.fromJson(Map<dynamic, dynamic> json) {
    userActivity = json['userActivity'] != null
        ? new UserActivity.fromJson(json['userActivity'])
        : null;

    totalError = json['totalError'];

    performance = json['performance'] != null
        ? new Performance.fromJson(json['performance'])
        : null;

    appName = json['appName'];


    time = json['time'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    if (this.userActivity != null) {
      data['userActivity'] = this.userActivity!.toJson();
    }
    data['totalError'] = this.totalError;
    if (this.performance != null) {
      data['performance'] = this.performance!.toJson();
    }
    data['appName'] = this.appName;
    data['time'] = this.time;
    return data;
  }

  @override
  toString() {
    return "userActivity: " + userActivity.toString() + ", appName: " + appName!;
  }

}

 Future testDataFunktion() async {
    String backendjsondata = '{"dashboard":{"userActivity":{"total":17,"logins":50,"active":1,"inactive":5,"loginsPerHourLst":[0,0,0,0,0,0,0,4,11,13,3,3,0,0,10,6],"hourLst":["0","1","2","3","4","5","6","7","8","9","10","11","12","13","14","15"],"online":6},"totalError":1,"performance":{"loadTimePagesLst":[583,289,154,105,16,13,4,583,0,0],"totalPageViewsPerHourLst":[0,0,0,0,0,0,0,14,82,104,52,85,9,89,114,34],"hourLst":["0","1","2","3","4","5","6","7","8","9","10","11","12","13","14","15"],"totalPageViews":583},"appName":"intranet","time":"January, 24 2022 15:50:48"}}';
 
     Map<String, dynamic> data = jsonDecode(backendjsondata);

   
     Dashboard dashboard = Dashboard.fromJson(data);
     print(dashboard);

Answer 1

Try:

 Future testDataFunktion() async {
   String backendjsondata = '{"dashboard":{"userActivity":{"total":17,"logins":50,"active":1,"inactive":5,"loginsPerHourLst":[0,0,0,0,0,0,0,4,11,13,3,3,0,0,10,6],"hourLst":["0","1","2","3","4","5","6","7","8","9","10","11","12","13","14","15"],"online":6},"totalError":1,"performance":{"loadTimePagesLst":[583,289,154,105,16,13,4,583,0,0],"totalPageViewsPerHourLst":[0,0,0,0,0,0,0,14,82,104,52,85,9,89,114,34],"hourLst":["0","1","2","3","4","5","6","7","8","9","10","11","12","13","14","15"],"totalPageViews":583},"appName":"intranet","time":"January, 24 2022 15:50:48"}}';

 
   Dashboard dashboard = Dashboard.fromJson(Map.from(jsonDecode(backendjsondata)));
   print(dashboard);
}