Flutter - Search using provider

main.dart

// This code is distributed under the MIT License.
// Copyright (c) 2019 Remi Rousselet.
// You can find the original at https://github.com/rrousselGit/provider.

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

void main() {
  runApp(
    const MyApp(),
  );
}

class ApiCall {
  static getAllProducts() async {
    final url = Uri.https('dummyjson.com', '/products');

    return await _getProducts(url);
  }

  static search(String val) async {
    final url = Uri.https(
      'dummyjson.com',
      '/products/search',
      {'q': val},
    );

    return await _getProducts(url);
  }

  static _getProducts(Uri url) async {
    print(url);

    // Await the HTTP GET response, then decode the
    // JSON data it contains.
    final response = await http.get(url);

    if (response.statusCode == 200) {
      final jsonResponse = convert.jsonDecode(response.body);
      final items = jsonResponse['products'];
      print('Number of books about HTTP: $items');
      return items;
    } else {
      print('Request failed with status: ${response.statusCode}.');
    }
  }
}

class SearchProvider with ChangeNotifier, DiagnosticableTreeMixin {
  List<dynamic>? _items;
  List<dynamic>? get items => _items;

  void searchItems(String val) async {
    _items = await ApiCall.search(val);
    notifyListeners();
  }

  void getAll() async {
    _items = await ApiCall.getAllProducts();
    notifyListeners();
  }
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  SearchProvider _provider = SearchProvider();

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _provider.getAll();
    });
  }

  @override
  Widget build(BuildContext context) {
//     final c = context.watch<Counter>();
    return Scaffold(
      appBar: AppBar(
        title: const Text('Provider example'),
      ),
      body: ChangeNotifierProvider<SearchProvider>(
          create: (_) => _provider,
          child: Column(
            children: [
              Padding(
                padding: const EdgeInsets.symmetric(horizontal: 15.0),
                child: TextField(
                  onSubmitted: (val) {
                    if(val.length > 0){
                    _provider.searchItems(val);
                    }
                    else {
                      _provider.getAll();
                    }
                  },
                  decoration: const InputDecoration(
                    labelText: 'Search',
                    suffixIcon: Icon(Icons.search),
                  ),
                ),
              ),
              Expanded(
                child:
                    Consumer<SearchProvider>(builder: (context, provider, w) {
                  if (provider.items != null && provider.items!.isNotEmpty) {
                    print(provider.items);
                    return SearchList(list: provider.items);
                  }
                  return const Center(
                    child: Text("Nothing found"),
                  );
                }),
              )
            ],
          )),
    );
  }
}

class SearchList extends StatelessWidget {
  final List<dynamic>? list;
  const SearchList({Key? key, required this.list}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      itemCount: list!.length,
      itemBuilder: (context, index) {
        return ListTile(
          leading: CircleAvatar(
              backgroundImage: NetworkImage(
            list![index]["thumbnail"],
          )),
          title: Text(list![index]["title"]),
        );
      },
    );
  }
}