import 'dart:async';

import 'dart:io';

​

import 'package:camera/camera.dart';

import 'package:flutter/material.dart';

​

Future<void> main() async {

  // Ensure that plugin services are initialized so that `availableCameras()`

  // can be called before `runApp()`

  WidgetsFlutterBinding.ensureInitialized();

​

  // Obtain a list of the available cameras on the device.

  final cameras = await availableCameras();

​

  // Get a specific camera from the list of available cameras.

  final firstCamera = cameras.first;

​

  runApp(

    MaterialApp(

      theme: ThemeData.dark(),

      home: TakePictureScreen(

        // Pass the appropriate camera to the TakePictureScreen widget.

        camera: firstCamera,

      ),

    ),

  );

}

​

// A screen that allows users to take a picture using a given camera.

class TakePictureScreen extends StatefulWidget {

  const TakePictureScreen({

    Key? key,

    required this.camera,

  }) : super(key: key);

​

  final CameraDescription camera;

​

  @override

  TakePictureScreenState createState() => TakePictureScreenState();

}

​

class TakePictureScreenState extends State<TakePictureScreen> {

  late CameraController _controller;

  late Future<void> _initializeControllerFuture;

​

  @override

  void initState() {

    super.initState();

    // To display the current output from the Camera,

    // create a CameraController.

    _controller = CameraController(

      // Get a specific camera from the list of available cameras.

      widget.camera,

      // Define the resolution to use.

      ResolutionPreset.medium,

    );

​

    // Next, initialize the controller. This returns a Future.

    _initializeControllerFuture = _controller.initialize();

  }

​

  @override

  void dispose() {

    // Dispose of the controller when the widget is disposed.

    _controller.dispose();

    super.dispose();

  }

​

  @override

  Widget build(BuildContext context) {

    return Scaffold(

      appBar: AppBar(title: const Text('Take a picture')),

      // You must wait until the controller is initialized before displaying the

      // camera preview. Use a FutureBuilder to display a loading spinner until the

      // controller has finished initializing.

      body: FutureBuilder<void>(

        future: _initializeControllerFuture,

        builder: (context, snapshot) {

          if (snapshot.connectionState == ConnectionState.done) {

            // If the Future is complete, display the preview.

            return CameraPreview(_controller);

          } else {

            // Otherwise, display a loading indicator.

            return const Center(child: CircularProgressIndicator());

          }

        },

      ),

      floatingActionButton: FloatingActionButton(

        // Provide an onPressed callback.

        onPressed: () async {

          // Take the Picture in a try / catch block. If anything goes wrong,

          // catch the error.

          try {

            // Ensure that the camera is initialized.

            await _initializeControllerFuture;

​

            // Attempt to take a picture and get the file `image`

            // where it was saved.

            final image = await _controller.takePicture();

​

            // If the picture was taken, display it on a new screen.

            await Navigator.of(context).push(

              MaterialPageRoute(

                builder: (context) => DisplayPictureScreen(

                  // Pass the automatically generated path to

                  // the DisplayPictureScreen widget.

                  imagePath: image.path,

                ),

              ),

            );

          } catch (e) {

            // If an error occurs, log the error to the console.

            print(e);

          }

        },

        child: const Icon(Icons.camera_alt),

      ),

    );

  }

}

​

// A widget that displays the picture taken by the user.

class DisplayPictureScreen extends StatelessWidget {

  final String imagePath;

​

  const DisplayPictureScreen({Key? key, required this.imagePath})

      : super(key: key);

​

  @override

  Widget build(BuildContext context) {

    return Scaffold(

      appBar: AppBar(title: const Text('Display the Picture')),

      // The image is stored as a file on the device. Use the `Image.file`

      // constructor with the given path to display the image.

      body: Image.file(File(imagePath)),

    );

  }

}