Dog Camera step 1

dogcamera1.dart

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:camera/camera.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key}) : super(key: key);
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  CameraController _controller;
  bool _cameraInitialized = false;
  String _topText = '';

  @override
  void initState() {
    super.initState();
    SystemChrome.setEnabledSystemUIOverlays([SystemUiOverlay.bottom]);
    SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle.dark);
    _initializeCamera();
  }

  void _initializeCamera() async {
    _topText = 'Waiting for camera initialization\n';
    List<CameraDescription> cameras = await availableCameras();
    _controller = CameraController(cameras[0], ResolutionPreset.medium);
    _controller.initialize().then((_) {
      _cameraInitialized = true;
      _topText = 'Camera initialization complete\n';
      setState(() {});
    });
  }

  @override
  void dispose() {
    _controller?.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButtonLocation: FloatingActionButtonLocation.centerFloat,
      body: Container(
        color: Colors.black,
        // constraints: const BoxConstraints.expand(),
        child: Column(
          children: <Widget>[
            Text(
              _topText,
              style: TextStyle(color: Colors.white, fontSize: 18),
            ),
            _cameraInitialized
                ? Expanded(
                    child: OverflowBox(
                        maxWidth: double.infinity,
                        child: AspectRatio(
                            aspectRatio: _controller.value.aspectRatio,
                            child: CameraPreview(_controller))))
                : Container(),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        backgroundColor: Colors.white,
      ),
    );
  }
}