Getting null instead of List of strings flutter json - json

Question

I'm making a recipes app that request the data form edamam Api and shows it in a listview.builder i have home screen class that make the request and shows the data
import 'package:flutter/material.dart';
import 'package:flutter_application_1/info_screen.dart';
import 'package:flutter_application_1/recipes.dart';
import 'dart:convert' as cnv;
import 'package:http/http.dart' as http;
class HomeScreen extends StatefulWidget {
const HomeScreen({Key? key}) : super(key: key);
#override
_HomeScreen createState() => _HomeScreen();
}
class _HomeScreen extends State<HomeScreen> {
//List<MissedIngredients>? missedIngredients;
List<Recipe>? results;
int path = 0;
int? numberOfIngredants;
int numberOfRequestedRecipes = 3;
String? foodName;
#override
void initState() {
// TODO: implement initState
super.initState();
getData();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Food recipe api'),
),
body: results == null
? Center(
child: CircularProgressIndicator(),
)
: ListView.builder(
itemBuilder: (BuildContext context, int index) {
return Card(
child: ListTile(
title: Text(results![index].label.toString()),
leading: Image.network(results![index].image.toString()),
onTap: () {
setState(() {
foodName = results![index].label.toString();
print(foodName);
});
},
));
},
itemCount: numberOfRequestedRecipes),
floatingActionButton: FloatingActionButton(
child: Icon(Icons.add_circle),
onPressed: () {
numberOfRequestedRecipes = numberOfRequestedRecipes + 10;
setState(() {
getData();
});
},
),
);
}
Future<void> getData() async {
http.Response res = await http.get(Uri.parse(
'https://api.edamam.com/api/recipes/v2?type=public&q=pizza&app_id=4dd9eafd&app_key=f2fa2c38ec16944f522dc9b734424cf4'));
print(res.body);
List<dynamic> body = cnv.jsonDecode(res.body)['hits'];
results = body.map((dynamic item) => Recipe.fromJson(item)).toList();
setState(() {});
}
}
and a recipes class that analyze the data so i can show it in the home screen
class recipes {
int ?from;
int ?to;
int ?count;
Links ?lLinks;
List<Hits> ?hits;
recipes({this.from, this.to, this.count, this.lLinks, this.hits});
recipes.fromJson(Map<String, dynamic> json) {
from = json['from'];
to = json['to'];
count = json['count'];
lLinks = json['_links'] != null ? new Links.fromJson(json['_links']) : null;
if (json['hits'] != null) {
hits = <Hits>[];
json['hits'].forEach((v) {
hits!.add(new Hits.fromJson(v));
});
}
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['from'] = this.from;
data['to'] = this.to;
data['count'] = this.count;
if (this.lLinks != null) {
data['_links'] = this.lLinks!.toJson();
}
if (this.hits != null) {
data['hits'] = this.hits!.map((v) => v.toJson()).toList();
}
return data;
}
}
class Links {
Next ? next;
Links({required this.next});
Links.fromJson(Map<String, dynamic> json) {
next = (json['next'] != null ? new Next.fromJson(json['next']) : null)!;
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
if (this.next != null) {
data['next'] = this.next!.toJson();
}
return data;
}
}
class Next {
String ?href;
String ?title;
Next({this.href, this.title});
Next.fromJson(Map<String, dynamic> json) {
href = json['href'];
title = json['title'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['href'] = this.href;
data['title'] = this.title;
return data;
}
}
class Hits {
Recipe ? recipe;
Links ? lLinks;
Hits({this.recipe, this.lLinks});
Hits.fromJson(Map<String, dynamic> json) {
recipe =
json['recipe'] != null ? new Recipe.fromJson(json['recipe']) : null;
lLinks = json['_links'] != null ? new Links.fromJson(json['_links']) : null;
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
if (this.recipe != null) {
data['recipe'] = this.recipe!.toJson();
}
if (this.lLinks != null) {
data['_links'] = this.lLinks!.toJson();
}
return data;
}
}
class Recipe {
String ?uri;
String ?label;
String ?image;
String ?source;
String ?url;
String ?shareAs;
int ?yield;
Recipe(
{this.uri,
this.label,
this.image,
this.source,
this.url,
this.shareAs,
this.yield,
});
Recipe.fromJson(Map<String, dynamic> json) {
uri = json['uri'];
label = json['label'];
image = json['image'];
source = json['source'];
url = json['url'];
shareAs = json['shareAs'];
yield = json['yield'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['uri'] = this.uri;
data['label'] = this.label;
data['image'] = this.image;
data['source'] = this.source;
data['url'] = this.url;
data['shareAs'] = this.shareAs;
data['yield'] = this.yield;
return data;
}
}
class Ingredients {
String? text;
double? weight;
String? foodCategory;
String? foodId;
String? image;
Ingredients(
{this.text, this.weight, this.foodCategory, this.foodId, this.image});
Ingredients.fromJson(Map<String, dynamic> json) {
text = json['text'];
weight = json['weight'];
foodCategory = json['foodCategory'];
foodId = json['foodId'];
image = json['image'];
}
Map<String, dynamic> toJson() {
final Map<String, dynamic> data = new Map<String, dynamic>();
data['text'] = this.text;
data['weight'] = this.weight;
data['foodCategory'] = this.foodCategory;
data['foodId'] = this.foodId;
data['image'] = this.image;
return data;
}
}
but when I run the app all I get is a null value so what is the problem
thank you for your valuable time!

Answer 1

Hi the Simplest Solution for your problem is to use a FutureBuilder
If you use the Widget build,
the method will run simultaneous with the init method,due to which you might receive null values even when values are in process of fetching . So use a future builder of type bool and use only when there's data !=null.