StatefulWidget Flutter

A StatefulWidget is a class that contains mutable state. Used when some part of the UI you are creating may change dynamically and you want the UI to reflect those changes.

Here's a simple example of using a StatefulWidget Flutter:

File open lib->main.dart file −

import 'package:flutter/material.dart';

void main() {
  runApp(
    MyApp()
  );
}
class MyApp extends StatefulWidget{

  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  
  @override
  Widget build(BuildContext context) {
    return   MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          backgroundColor: Colors.blue,
          title: Text('StatefulWidget Example',
              style:TextStyle(fontSize: 20,color: Colors.white)),
        ),
        body:Container(
          alignment: Alignment.center,
            child: Text("Stateful Widget",style: TextStyle(fontSize: 20),))
      ),
    );

  }
}

Open Device Manager, run the emulator, and then run the application. Next, check the working output and check the output you declared in your code.

Output: