StreamBuilder(

  stream: widget.channel.stream,

  builder: (context, snapshot) {

    return Text(snapshot.hasData ? '${snapshot.data}' : '');

  },

);

import 'dart:async';

import 'dart:convert';

import 'package:flutter/material.dart';

import 'package:http/http.dart' as http;

Future fetchAlbum() async {

  final response =

  await http.get('https://jsonplaceholder.typicode.com/albums/1');

  if (response.statusCode == 200) {

    return Album.fromJson(json.decode(response.body));

  } else {

    throw Exception('Loading album failed!');

  }

}

Future updateAlbum(String title) async {

  final http.Response response = await http.put(

    'https://jsonplaceholder.typicode.com/albums/1',

    headers: {

      'Content-Type': 'application/json; charset=UTF-8',

    },

    body: jsonEncode({

      'title': title,

    }),

  );

  if (response.statusCode == 200) {

    return Album.fromJson(json.decode(response.body));

  } else {

    throw Exception('Failed to update the album!');

  }

}

// the album class

class Album {

  final int id;

  final String title;

  Album({this.id, this.title});

  factory Album.fromJson(Map json) {

    return Album(

      id: json['id'],

      title: json['title'],

    );

  }

}

void main() {

  runApp(MyApp());

}

class MyApp extends StatefulWidget {

  MyApp({Key key}) : super(key: key);

  @override

  _MyAppState createState() {

    return _MyAppState();

  }

}

class _MyAppState extends State {

  final TextEditingController _controller = TextEditingController();

  Future _futureAlbum;

  @override

  void initState() {

    super.initState();

    _futureAlbum = getAlbum();

  }

  @override

  Widget build(BuildContext context) {

    return MaterialApp(

      title: 'Update Data',

      theme: ThemeData(

        primarySwatch: Colors.blue,

      ),

      home: Scaffold(

        appBar: AppBar(

          title: Text('GeeksForGeeks'),

          backgroundColor: Colors.green,

        ),

        body: Container(

          alignment: Alignment.center,

          padding: const EdgeInsets.all(8.0),

          child: FutureBuilder(

            future: _futureAlbum,

            builder: (context, snapshot) {

              if (snapshot.connectionState == ConnectionState.done) {

                if (snapshot.hasData) {

                  return Column(

                    mainAxisAlignment: MainAxisAlignment.center,

                    children: [

                      Text(snapshot.data.title),

                      TextField(

                        controller: _controller,

                        decoration: InputDecoration(hintText: 'Enter Title'),

                      ),

                      RaisedButton(

                        child: Text('Update Data'),

                        onPressed: () {

                          setState(() {

                            _futureAlbum = updateAlbum(_controller.text);

                          });

                        },

                      ),

                    ],

                  );

                } else if (snapshot.hasError) {

                  return Text("${snapshot.error}");

                }

              }

              return CircularProgressIndicator();

            },

          ),

        ),

      ),

    );

  }

}