Future builder example

main.dart

import 'dart:convert';

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Example',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.teal,
      ),
      home: StarterPage(),
    );
  }
}

class StarterPage extends StatefulWidget {
  @override
  State<StarterPage> createState() => _StarterPageState();
}

class _StarterPageState extends State<StarterPage> {
  Future<List<dynamic>> _getPolicy() async {
    final url =
        Uri.parse('https://jsonplaceholder.typicode.com/todos?userId=1');

    try {
      final response = await http.get(url);
      return json.decode(response.body);
    } catch (error) {
      print('---error-');
      rethrow;
    }
  }

  late Future<List<dynamic>> _loadedProducts;

  @override
  void initState() {
    _loadedProducts = _getPolicy();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Starter Page')),
      body: FutureBuilder<List<dynamic>>(
        future: _loadedProducts,
        builder: (context, AsyncSnapshot<List<dynamic>> snapshot) {
          if (snapshot.hasData &&
              snapshot.data != null &&
              snapshot.data!.isNotEmpty) {
            return AnimatedList(
              initialItemCount: snapshot.data!.length,
              itemBuilder:
                  (BuildContext context, int index, Animation animation) {
                return Text(snapshot.data![index]['title']);
              },
            );
          } else if (snapshot.hasError) {
            return Text("${snapshot.error}");
          }

          // By default, show a loading spinner.
          return const CircularProgressIndicator();
        },
      ),
    );
  }
}