Flutter async methods for widget initialize - flutter

Question

Let's say I create a new screen team_screen which is the first parent of the tree.
Now for my team screen there are many widgets, some of theme have their own request, I want to show loader until every widget/request finished and ready.
I thought on 2 approaches.
All the requests are executed in team_screen with future builder and I pass the props to my widgets by demand.
Every widget with request get function that get executed in the async function in the initState function, then in my parent I make to every widget state parameter that is equal to true by the function I passed and when all is don't I stop the loader.
To sum up my problem is how to maintain a widget with many children and requests and showing one loader for entire page, making all the request on same widget? Pass isInitialize function to every widget?.
Which approach is better and if there are more approaches, I would like to hear.
Thank you for your help
Example for the second approach:
import 'package:flutter/material.dart';
import 'package:info_striker/locator.dart';
import 'package:info_striker/models/fixture/fixture.dart';
import 'package:info_striker/models/odds/bookmaker.dart';
import 'package:info_striker/models/synced-team/synced_team.dart';
import 'package:info_striker/services/fixture_service.dart';
import 'package:info_striker/utils/date_utilities.dart';
class TeamNextMatch extends StatefulWidget {
Function isInitialized;
SyncedTeam team;
TeamNextMatch({
Key? key,
required this.isInitialized,
required this.team,
}) : super(key: key);
#override
State<TeamNextMatch> createState() => _TeamNextMatchState();
}
class _TeamNextMatchState extends State<TeamNextMatch> {
Fixture? _fixture;
Bookmaker? _matchResult;
bool _isInitialized = false;
#override
void initState() {
super.initState();
init();
}
init() async {
final response = await locator<FixturesService>().getData(widget.team.id);
if (response != null) {
setState(() {
_fixture = Fixture.fromMap(response["fixture"]);
_matchResult = Bookmaker.fromMap(response["matchResultOdds"]);
});
}
widget.isInitialized(true);
}
#override
Widget build(BuildContext context) {
String? _date;
bool show = _fixture != null && _matchResult != null;
_fixture != null ? "${DateUtilities.getShortDateString(_fixture!.date)}, ${DateUtilities.getTimeString(_fixture!.date)}" : null;
return show
? Column(
children: [
Text(_fixture?.league?["name"]),
if (_date != null) Text(_date),
],
)
: const SizedBox();
}
}

Answer 1

You can show loader as described below -
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:flutter_application_1/data_model.dart';
import 'package:http/http.dart' as http;
class APiTest extends StatefulWidget {
const APiTest({Key? key}) : super(key: key);
#override
_APiTestState createState() => _APiTestState();
}
class _APiTestState extends State<APiTest> {
final String _url = "https://jsonplaceholder.typicode.com/todos/";
bool _isLoading = true;
final List<DataModel> _allData = [];
#override
void initState() {
super.initState();
_initData().then((value) {
setState(() {
_isLoading = false;
});
});
}
Future<void> _initData() async {
final response = await http.get(Uri.parse(_url));
final List res = jsonDecode(response.body);
res.forEach((element) {
_allData.add(DataModel.fromJson(element));
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("Loading Demo"),
),
body: Stack(
children: [
ListView.separated(
itemCount: _allData.length,
controller: ScrollController(),
separatorBuilder: (_, __) => const SizedBox(height: 10),
itemBuilder: ((context, index) {
return ListTile(
tileColor: Colors.grey[200],
title: Text(_allData[index].title!),
subtitle: Text(_allData[index].id.toString()),
);
}),
),
if (_isLoading)
const Center(
child: CircularProgressIndicator(),
)
],
),
);
}
}