How to setState http url? - json

Question

I want to create a news app and I've used newsapi.org as well but The
problem is actually that I want to make something like search feature in my
app and my idea is very simple.
I've created a TextField in the AppBar and my idea is to take the input from
user and setState with the new url of user input.
My Code:
import 'package:flutter/material.dart';
import 'package:newly/services/networking.dart';
import 'package:newly/widgets/article.dart';
class NewsScreen extends StatefulWidget {
#override
_NewsScreenState createState() => _NewsScreenState();
}
class _NewsScreenState extends State<NewsScreen> {
List<Article> articles = [];
String topic = 'google';
var newsData;
Future getNews(String topic) async {
NetworkHelper networkHelper = NetworkHelper(
url:
'https://newsapi.org/v2/everything?q=$topic&from=2019-11-04&to=2019-11-04&sortBy=popularity&apiKey=392495172bab4b3885ae93760df54b91',
);
newsData = await networkHelper.getData();
for (int i = 0; i < newsData['articles'].length; i++) {
var title = newsData['articles'][i]['title'];
var urlToImage = newsData['articles'][i]['urlToImage'];
var content = newsData['articles'][i]['content'];
var author = newsData['articles'][i]['author'];
var url = newsData['articles'][i]['url'];
setState(() {
articles.add(
Article(
author: author,
content: content,
title: title,
url: url,
urlToImage: urlToImage,
),
);
});
}
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.black,
centerTitle: true,
title: TextField(
textInputAction: TextInputAction.search,
onChanged: (String text) async {
setState(() {
topic = text;
});
await getNews(topic);
print(topic);
},
onSubmitted: (String text) async {
setState(() {
topic = text;
});
print(topic);
await getNews(topic);
},
decoration: InputDecoration(
suffixIcon: IconButton(
onPressed: () async {
await getNews(topic);
print(topic);
},
icon: Icon(
Icons.search,
),
),
hintText: 'Search',
filled: true,
fillColor: Colors.white,
),
),
),
body: SafeArea(
child: Padding(
padding: const EdgeInsets.all(15.0),
child: FutureBuilder(
future: getNews(topic),
builder: (context, snapshot) {
return ListView.builder(
itemCount: newsData['articles'] == null
? 0
: newsData['articles'].length,
itemBuilder: (BuildContext ctxt, int index) {
return Article(
author: articles[index].author,
content: articles[index].content,
title: articles[index].title,
url: articles[index].url,
urlToImage: articles[index].urlToImage,
);
},
);
},
),
),
),
);
}
}
Network Helper :
import 'package:http/http.dart' as http;
import 'dart:convert';
class NetworkHelper {
NetworkHelper({this.url});
final String url;
Future getData() async {
http.Response response = await http.get(url);
if (response.statusCode == 200) {
String data = response.body;
return json.decode(data);
} else {
print('something wrong');
print(response.statusCode);
}
}
}