StatefulWidget LifeCycle Example

 import "package:flutter/material.dart";

void main()
{
  runApp(const MyApp());
}
class MyApp extends StatelessWidget
{
  const MyApp({super.key});
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "StatefulWidget LifeCycle",
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.grey,
      ),
      home: const StatefulWidgetLifeCycle(),
    );
  }
}
class StatefulWidgetLifeCycle extends StatefulWidget
{
  const StatefulWidgetLifeCycle({super.key});
  @override
  State<StatefulWidgetLifeCycle> createState()
  {
    return StatefulWidgetLifeCycleState();
  }
}
class StatefulWidgetLifeCycleState extends State<StatefulWidgetLifeCycle>
{
  final Color _containerColor = Colors.yellow;

  void changeColor()
  {
    setState(() {
      if(_containerColor == Colors.yellow)
        {
          _containerColor == Colors.red;
          return;
        }
      _containerColor == Colors.yellow;
    },);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("StatefulWidget LifeCycle Example"),
        centerTitle: true,
        backgroundColor: Colors.grey,
      ),
      body: Container(
        decoration: BoxDecoration(
          color: _containerColor,
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: changeColor,
        child: const Icon(Icons.add),
      ),
    );
  }
}