content: import 'package:flutter/material.dart';
  import 'package:url_launcher/url_launcher.dart';
  
  class Day5Opacity extends StatefulWidget {
    Day5Opacity({Key key}) : super(key: key);
  
    @override
    _Day5OpacityState createState() => _Day5OpacityState();
  }
  
  class _Day5OpacityState extends State<Day5Opacity> {
    bool _opacity = false;
    @override
    Widget build(BuildContext context) {
      bool checkAnimation =
          true; // ! change here to find the differents between the Opacity and AnimatedOpacity....
  
      var withAnimation = AnimatedOpacity(
        // ? what is AnimatedOpacity....
        duration: Duration(milliseconds: 500),
        /**
         * ! Yes we can perform the animation with the help of [duration] property in AnimatedOpacity....
         */
        opacity: _opacity ? 0.0 : 1.0,
        /**
         * ! [opacity] is the property for make hide and perform the transparency in child....
         * ! we can specify the values between 0.0 to 1.0....
         * ! 0.0 - transparent....
         * ! 1.0 - visible....  
         */
  
        child: Center(
          child: Container(
            width: 250,
            height: 250,
            color: Colors.deepPurple,
          ),
        ),
      );
  
      var withoutAnimation = Opacity(
        // ? what is Opacity....
  
        opacity: _opacity ? 0.0 : 1.0,
        /**
         * ! [opacity] is the property for make hide and perform the transparency in child....
         * ! we can specify the values between 0.0 to 1.0....
         * ! 0.0 - transparent....
         * ! 1.0 - visible....  
         */
        child: Center(
          child: Container(
            width: 250,
            height: 250,
            color: Colors.deepPurple,
          ),
        ),
      );
  
      return Scaffold(
        appBar: AppBar(
          title: Text("Opacity"),
          actions: <Widget>[
            IconButton(
              icon: Icon(Icons.help),
              onPressed: () async {
                const url =
                    'https://github.com/sanjaysanju618/100-Days-Of-Flutter-Widgets/' +
                        'blob/master/hundred_days_of_flutter_widget/' +
                        'lib/day005_opacity.dart';
                if (await canLaunch(url)) {
                  await launch(url);
                } else {
                  throw 'Could not launch $url';
                }
              },
            )
          ],
        ),
        body: SafeArea(
          child: GestureDetector(
            onTap: () {
              setState(() {
                _opacity = !_opacity;
              });
            },
            child: checkAnimation ? withAnimation : withoutAnimation,
          ),
        ),
      );
    }
  }
  