How to fetch json data and separate it based on a Parameter? - flutter

Question

I have a json object here -
{
"error": "0",
"message": "Got it!",
"data": [
{
"status": false,
"_id": "5e2fbb74d465702288c54038",
"group_id": "5e0d9e993944e46ed9a86d95",
"date": "2020-01-28T00:00:00.000Z",
"title": "cciigcigc",
"priority": 3,
"description": "",
"tasks": [],
"created_date": "2020-01-28T04:41:24.576Z",
"__v": 0
}
]
}
I want to fetch it based on the ["data"]["status"] parameter; if the status is false, return a seperate list and if the status is true, return another list. I have tried to modify my current fetch method this way -
Future<List<Post>> gettask(bool identifier) async { // the identifier can be set to true and false
List<Post> statusComplete;
List<Post> statusInComplete;
String link = baseURL + fetchTodoByDate;
// print("printing from get task = $setter");
Stopwatch stopwatchbefore = new Stopwatch()..start();
var res = await http.post(Uri.encodeFull(link), headers: {"Accept": "application/json", }, body: {"date" : setter.toString()});
print('fetch executed in ${stopwatchbefore.elapsed}');
if (res.statusCode == 200) {
Stopwatch stopwatchafter = new Stopwatch()
..start();
var data = json.decode(res.body);
var rest = data["data"] as List;
if(identifier == true){
statusComplete = rest.map<Post>((json) {
// need help in implementing logic here
return Post.fromJson(json);
}).toList();
return statusComplete;
}else if(identifier == false){
statusInComplete = rest.map<Post>((json) {
// need help in implementing logic here
return Post.fromJson(json);
}).toList();
return statusInComplete;
}
print('statuscode executed in ${stopwatchafter.elapsed}');
Future.delayed(Duration(seconds: 5));
}
// print("List Size: ${list.length}");
}
This is the first time I am trying to fetch and separate the data this way. I have tried to look at some tutorials but none seemed to be satisfying my case.
Could i get some suggestion on how to fetch the data and then separate it based on a parameter?

Answer 1

check out the example below which will give the basic idea how the flow works.
import 'package:flutter/material.dart';
import 'dart:async';
import 'package:flutter/services.dart';
import 'package:json_parsing/models.dart';
void main() => runApp(MyApp());
class MyApp extends StatefulWidget {
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
List<Datum> dataList = List();
bool _isLoading = false;
Future<String> loadFromAssets() async {
return await rootBundle.loadString('json/parse.json');
}
Future loadyourData() async {
setState(() {
_isLoading = true;
});
// this is the local json that i have loaded from the assets folder
// you can make the http call here and else everything later is the same.
String jsonString = await loadFromAssets();
final yourData = dataFromJson(jsonString);
dataList = yourData.data;
var statusComplete = dataList.where((i) => i.status == true).toList();
for (int i = 0; i < statusComplete.length; i++) {
print('This is the list for true status :${statusComplete[i].title}');
}
var statusInComplete = dataList.where((i) => i.status == false).toList();
print(statusInComplete[0].title);
setState(() {
_isLoading = false;
});
}
#override
void initState() {
super.initState();
loadyourData();
}
#override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
home: Scaffold(
body: Container(
child: _isLoading
? CircularProgressIndicator()
: new ListView.builder(
itemCount: dataList.length,
itemBuilder: (BuildContext ctxt, int index) {
return new Text(dataList[index].status.toString());
}),
)),
);
}
}
below is the model class
// To parse this JSON data, do
//
// final data = dataFromJson(jsonString);
import 'dart:convert';
Data dataFromJson(String str) => Data.fromJson(json.decode(str));
String dataToJson(Data data) => json.encode(data.toJson());
class Data {
String error;
String message;
List<Datum> data;
Data({
this.error,
this.message,
this.data,
});
factory Data.fromJson(Map<String, dynamic> json) => Data(
error: json["error"],
message: json["message"],
data: List<Datum>.from(json["data"].map((x) => Datum.fromJson(x))),
);
Map<String, dynamic> toJson() => {
"error": error,
"message": message,
"data": List<dynamic>.from(data.map((x) => x.toJson())),
};
}
class Datum {
bool status;
String id;
String groupId;
DateTime date;
String title;
int priority;
String description;
List<dynamic> tasks;
DateTime createdDate;
int v;
Datum({
this.status,
this.id,
this.groupId,
this.date,
this.title,
this.priority,
this.description,
this.tasks,
this.createdDate,
this.v,
});
factory Datum.fromJson(Map<String, dynamic> json) => Datum(
status: json["status"],
id: json["_id"],
groupId: json["group_id"],
date: DateTime.parse(json["date"]),
title: json["title"],
priority: json["priority"],
description: json["description"],
tasks: List<dynamic>.from(json["tasks"].map((x) => x)),
createdDate: DateTime.parse(json["created_date"]),
v: json["__v"],
);
Map<String, dynamic> toJson() => {
"status": status,
"_id": id,
"group_id": groupId,
"date": date.toIso8601String(),
"title": title,
"priority": priority,
"description": description,
"tasks": List<dynamic>.from(tasks.map((x) => x)),
"created_date": createdDate.toIso8601String(),
"__v": v,
};
}
and this is the json that you specified
{
"error": "0",
"message": "Got it!",
"data": [
{
"status": false,
"_id": "5e2fbb74d465702288c54038",
"group_id": "5e0d9e993944e46ed9a86d95",
"date": "2020-01-28T00:00:00.000Z",
"title": "first",
"priority": 3,
"description": "",
"tasks": [],
"created_date": "2020-01-28T04:41:24.576Z",
"__v": 0
},
{
"status": true,
"_id": "5e2fbb74d465702288c54038",
"group_id": "5e0d9e993944e46ed9a86d95",
"date": "2020-01-28T00:00:00.000Z",
"title": "second",
"priority": 3,
"description": "",
"tasks": [],
"created_date": "2020-01-28T04:41:24.576Z",
"__v": 0
},
{
"status": true,
"_id": "5e2fbb74d465702288c54038",
"group_id": "5e0d9e993944e46ed9a86d95",
"date": "2020-01-28T00:00:00.000Z",
"title": "third",
"priority": 3,
"description": "",
"tasks": [],
"created_date": "2020-01-28T04:41:24.576Z",
"__v": 0
}
]
}

Answer 2

Try this model class
import 'dart:convert';
Jsonmodel jsonmodelFromJson(String str) => Jsonmodel.fromJson(json.decode(str));
String jsonmodelToJson(Jsonmodel data) => json.encode(data.toJson());
class Jsonmodel {
String error;
String message;
List<Datum> data;
Jsonmodel({
this.error,
this.message,
this.data,
});
factory Jsonmodel.fromJson(Map<String, dynamic> json) => Jsonmodel(
error: json["error"],
message: json["message"],
data: List<Datum>.from(json["data"].map((x) => Datum.fromJson(x))),
);
Map<String, dynamic> toJson() => {
"error": error,
"message": message,
"data": List<dynamic>.from(data.map((x) => x.toJson())),
};
}
class Datum {
bool status;
String id;
String groupId;
DateTime date;
String title;
int priority;
String description;
List<dynamic> tasks;
DateTime createdDate;
int v;
Datum({
this.status,
this.id,
this.groupId,
this.date,
this.title,
this.priority,
this.description,
this.tasks,
this.createdDate,
this.v,
});
factory Datum.fromJson(Map<String, dynamic> json) => Datum(
status: json["status"],
id: json["_id"],
groupId: json["group_id"],
date: DateTime.parse(json["date"]),
title: json["title"],
priority: json["priority"],
description: json["description"],
tasks: List<dynamic>.from(json["tasks"].map((x) => x)),
createdDate: DateTime.parse(json["created_date"]),
v: json["__v"],
);
Map<String, dynamic> toJson() => {
"status": status,
"_id": id,
"group_id": groupId,
"date": date.toIso8601String(),
"title": title,
"priority": priority,
"description": description,
"tasks": List<dynamic>.from(tasks.map((x) => x)),
"created_date": createdDate.toIso8601String(),
"__v": v,
};
}
use like this
var res = await http.post(Uri.encodeFull(link), headers: {"Accept":
"application/json", }, body: {"date" : setter.toString()});
Jsonmodel modeldata = jsonmodelFromJson(res);
// do your stuff
modeldata.data.foreach((data){
if(data.status){
//do your stuff
}else{
//do your stuff
}
});