content: import 'package:flutter/material.dart';
  import 'package:url_launcher/url_launcher.dart';
  
  class Day29SizedBox extends StatelessWidget {
    const Day29SizedBox({Key key}) : super(key: key);
  
    @override
    Widget build(BuildContext context) {
      return Scaffold(
        appBar: AppBar(
          title: Text("SizedBox"),
          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/day029_sized_box.dart';
                if (await canLaunch(url)) {
                  await launch(url);
                } else {
                  throw 'Could not launch $url';
                }
              },
            )
          ],
        ),
        body: Center(
          child: SizedBox(
              // ? What is SizedBox....
              /**
               * ! Creates a fixed size box....
               * ! The [width] and [height] parameters can be null to indicate that the size of the box....
               * ! so that the chlid will set to the size of the box....
               */
              width: 250, // ? her we fix width to 250....
              height: 250, // ? her we fix height to 250....
              child: RaisedButton(
                // ! so that RaisedButton fixed to size 250x250....
                onPressed: () {},
                child: Text("Click Me...."),
              )),
        ),
      );
    }
  }
  