Flutter JSON data issue - node.js

Question

I'm facing issue to fetch json data from Flutter mobile app.
Code as follow:
import 'package:flutter/material.dart';
import 'package:flutter_app/pages/main_page.dart';
class App extends StatelessWidget
{
#override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
title: "Flutter NodeJS",
home: MainPage(),
);
}
}
void main(){
runApp(App());
}
main_page.dart
import 'package:flutter/material.dart';
import 'package:flutter_app/modules/http.dart';
import 'package:flutter_app/pages/add_user_page.dart';
class MainPage extends StatefulWidget
{
#override
State<StatefulWidget> createState() {
return MainPageState();
}
}
class User
{
String id;
String first_name,email;
User(this.id, this.first_name,this.email);
}
class MainPageState extends State<MainPage>
{
List<User> users = [];
Future<void> refreshUsers()async{
var result = await http_get('users');
if(result.ok)
{
setState(() {
users.clear();
var in_users = result.data as List<dynamic>;
in_users.forEach((in_user){
users.add(User(
in_user['id'].toString(),
in_user['first_name'],
in_user['email']
));
});
});
}
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Users"),
//email: Text("Email"),
actions: <Widget>[
IconButton(
icon: Icon(Icons.add),
onPressed: (){
Navigator.of(context).push(MaterialPageRoute(
builder: (context){
return AddUserPage();
}
));
},
)
],
),
body: RefreshIndicator(
onRefresh: refreshUsers,
child: ListView.separated(
itemCount: users.length,
itemBuilder: (context, i) => ListTile(
leading: Icon(Icons.person),
title: Text(users[i].first_name+"\n" + users[i].email),
//email: Text(users[i].email),
),
separatorBuilder: (context, i) => Divider(),
),
),
);
}
}
http.dart
import 'dart:convert';
import "package:http/http.dart" as http;
class RequestResult
{
bool ok;
dynamic data;
RequestResult(this.ok, this.data);
}
//'https://jsonplaceholder.typicode.com/users/1
//http://192.168.183.179:8081/api/users/
const PROTOCOL = "http";
const DOMAIN = "https://jsonplaceholder.typicode.com/users/1";
Future<RequestResult> http_get(String route, [dynamic data]) async
{
var dataStr = jsonEncode(data);
var url = "$PROTOCOL://$DOMAIN/$route?data=$dataStr";
var result = await http.get(url);
return RequestResult(true, jsonDecode(result.body));
}
Future<RequestResult> http_post(String route, [dynamic data]) async
{
var url = "$PROTOCOL://$DOMAIN/$route";
var dataStr = jsonEncode(data);
var result = await http.post(url, body: dataStr, headers:{"Content-Type":"application/json"});
return RequestResult(true, jsonDecode(result.body));
}
When I'm fetch json data from "https://jsonplaceholder.typicode.com/users/1". Its working fine.
enter image description here
When I try to fetch json data from "https://192.168.183.179:8081/api/users". Its give error:
at Object.createErrorWithStack (http://localhost:15340/dart_sdk.js:4348:12)
at Object._rethrow (http://localhost:15340/dart_sdk.js:37892:16)
at async._AsyncCallbackEntry.new.callback (http://localhost:15340/dart_sdk.js:37886:13)
at Object._microtaskLoop (http://localhost:15340/dart_sdk.js:37718:13)
at _startMicrotaskLoop (http://localhost:15340/dart_sdk.js:37724:13)
at http://localhost:15340/dart_sdk.js:33243:9
What I'm doing wrong
Regards,
SAO

Answer 1

Check in Postman whether the ip address is returning data.
Another case would be the data obtained, could not be transffered correctly to the app. Check the variables and types where the data is stored.