weather_app_layout_02.dart

@override
  Widget build(BuildContext context) {
    Size size = MediaQuery.of(context).size;
    return Scaffold(
      appBar: AppBar(
        title: Text('My Weather App'),
      ),
      body: SafeArea(
        child: Stack(
          children: <Widget>[
            Center(
              child: Image.asset(
                'assets/images/background.jpg',
                width: size.width,
                height: size.height,
                fit: BoxFit.fill,
              ),
            ),
            Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.spaceAround,
                children: <Widget>[
                  [...]
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }