Animated opacity

 import "package:flutter/material.dart";

void main() {
  runApp(AppShow(),);
}
class AppShow extends StatelessWidget {
  AppShow({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "Animated Opacity",
      theme: ThemeData(
        primarySwatch: Colors.brown,
      ),
      home: OpacityDemo(),
    );
  }
}
class OpacityDemo extends StatefulWidget {
  OpacityDemo({super.key});

  @override
  State<OpacityDemo> createState() {
    return AnimatedState();
  }
}
class AnimatedState extends State<OpacityDemo> {
  var myOpacity = 1.0;
  bool isVisible = true;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Animated Opacity"),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            AnimatedOpacity(
              opacity: myOpacity,
              duration: Duration(seconds: 1,),
              curve: Curves.slowMiddle,
              child: Container(
                width: 300.0,
                height: 200.0,
                color: Colors.blue,
              ),
            ),
            SizedBox(height: 30.0,),
            ElevatedButton(
              onPressed: () {
                setState(() {

                  if(isVisible) {
                    myOpacity = 0.0;
                    isVisible = false;
                  } else {
                    myOpacity = 1.0;
                    isVisible = true;
                  }

                },);
              },
              child: Text("Show Animation"),
            ),
          ],
        ),
      ),
    );
  }
}