future builder

import 'package:flutter/material.dart';
import 'dart:convert';
import 'package:http/http.dart' as http;
import 'dart:ui';
import 'dart:async';

void main()=>runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  String url='http://jsonplaceholder.typicode.com/posts';
  getData(){return http.get(url);}
  @override
  Widget build(BuildContext context) {
    getData();
    return Scaffold(
      appBar: AppBar(title: Text('Http Demo'),),
      body: FutureBuilder(
        future: getData(),
        builder: (BuildContext context, snapshot){
          if(!snapshot.hasData){
            return Container(
              width: window.physicalSize.width,
              height: window.physicalSize.height,
              color: Colors.lime,
              child: Padding(
                padding: const EdgeInsets.all(50),
                child: CircularProgressIndicator(),
              ),
            );
          }
          List datas=[];
          datas=jsonDecode(snapshot.data.body);
          return ListView.builder(
            itemCount: datas.length,
            itemBuilder: (BuildContext context,index){
              var data=datas[index];
              return ListTile(
                title: Text(data['title']),
                subtitle: Text(data['body']),
              );
            },
          );
        },
      ),
    );
  }
}