content: import 'package:flutter/material.dart';
  import 'package:url_launcher/url_launcher.dart';
  
  class Day50AnimatedOpacity extends StatefulWidget {
    Day50AnimatedOpacity({Key key}) : super(key: key);
  
    @override
    _Day50AnimatedOpacityState createState() => _Day50AnimatedOpacityState();
  }
  
  class _Day50AnimatedOpacityState extends State<Day50AnimatedOpacity> {
    var _animOpacity = true;
  
    @override
    Widget build(BuildContext context) {
      return Scaffold(
        body: SafeArea(
          child: GestureDetector(
            onTap: () {
              setState(() {
                _animOpacity = !_animOpacity;
              });
            },
            child: Center(
              /**
               * ? What is AnimatedOpacity....
               * ! AnimatedOpacity is the very cool widget for perfrom animation on the opacity....
               */
              child: AnimatedOpacity(
                opacity: _animOpacity
                    ? 1.0
                    : 0.5, // ! we can change the opacity value dynamicly between 0.0 - 1.0....
                duration: Duration(
                    seconds:
                        1), // ! and we needed to pass the time duration for animation....
                child: Container(
                  // ! child holds the element to be animated....
                  width: 250,
                  height: 250,
                  color: Colors.deepOrange,
                  child: Center(
                    child: Text(
                      "Click",
                      style: TextStyle(color: Colors.black, fontSize: 25),
                    ),
                  ),
                ),
              ),
            ),
          ),
        ),
        appBar: AppBar(
          title: Text("AnimatedOpacity"),
          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/day050_animated_opacity.dart';
                if (await canLaunch(url)) {
                  await launch(url);
                } else {
                  throw 'Could not launch $url';
                }
              },
            )
          ],
        ),
      );
    }
  }
  