await in initState

First you understand the concept of await in Flutter . Then you can easily understand that it is not possible to use await in initState because initState method is non-async and StatefulWidget lifecycle will not run smoothly, which will result in screen not loading, hence, adding await in initState is not recommended. Because initState is not marked as asynchronous. However await for a separate asynchronous method to be received or required and call it within initState.

In the below example fetchData method is aync and used in initState()

import 'package:flutter/material.dart';

class MyWidget extends StatefulWidget {
  @override
  _MyWidgetState createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  String data = 'Loading...';

  @override
  void initState() {
    super.initState();
//Here we call async function 
    fetchData();
  }

  Future<void> fetchData() async {
    //asynchronous operation, such as fetching data
    await Future.delayed(Duration(seconds: 2));
    // Update the state after the asynchronous operation
    setState(() {
      data = 'Data loaded successfully!';
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Async initState Example'),
      ),
      body: Center(
        child: Text(data),
      ),
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: MyWidget(),
  ));
}