آموزش استفاده از دوربین در برنامه نویسی فلاتر

 
dependencies:
  camera:
  path_provider:
  thumbnails:
    git:
      url: https://github.com/divyanshub024/Flutter_Thumbnails.git
  video_player:
  esys_flutter_share:

 
List<CameraDescription> _cameras;
@override
void initState() {
  _initCamera();
  super.initState();
}
Future<void> _initCamera() async {
  _cameras = await availableCameras();
}

CameraController _controller;

Future<void> _initCamera() async {
  _controller = CameraController(_cameras[0], ResolutionPreset.medium);
  _controller.initialize().then((_) {
    if (!mounted) {
      return;
    }
    setState(() {});
  });
}

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

@override
Widget build(BuildContext context) {
  if (_controller != null) {
    if (!_controller.value.isInitialized) {
      return Container();
    }
  } else {
    return const Center(
      child: SizedBox(
        width: 32,
        height: 32,
        child: CircularProgressIndicator(),
      ),
    );
  }
}

 return Scaffold(
  backgroundColor: Theme.of(context).backgroundColor,
  key: _scaffoldKey,
  extendBody: true,
  body: Stack(
    children: <Widget>[
      _buildCameraPreview(),
    ],
  ),
);

Widget _buildCameraPreview() {
  final size = MediaQuery.of(context).size;
  return ClipRect(
    child: Container(
      child: Transform.scale(
        scale: _controller.value.aspectRatio / size.aspectRatio,
        child: Center(
          child: AspectRatio(
            aspectRatio: _controller.value.aspectRatio,
            child: CameraPreview(_controller),
          ),
        ),
      ),
    ),
  );
}

body: Stack(
  children: <Widget>[
    _buildCameraPreview(),
    Positioned(
      top: 24.0,
      left: 12.0,
      child: IconButton(
        icon: Icon(
          Icons.switch_camera,
          color: Colors.white,
        ),
        onPressed: _onCameraSwitch,
      ),
    ),
  ],
),

 
Future<void> _onCameraSwitch() async {
  final CameraDescription cameraDescription =
      (_controller.description == _cameras[0]) ? _cameras[1] : _cameras[0];
  if (_controller != null) {
    await _controller.dispose();
  }
  _controller = CameraController(cameraDescription, ResolutionPreset.medium);
  _controller.addListener(() {
    if (mounted) setState(() {});
    if (_controller.value.hasError) {
      showInSnackBar('Camera error ${_controller.value.errorDescription}');
    }
  });

  try {
    await _controller.initialize();
  } on CameraException catch (e) {
    _showCameraException(e);
  }

  if (mounted) {
    setState(() {});
  }
}

return Scaffold(
  backgroundColor: Theme.of(context).backgroundColor,
  key: _scaffoldKey,
  extendBody: true,
  body: ...
  bottomNavigationBar: _buildBottomNavigationBar(),
);

 
Widget _buildBottomNavigationBar() {
  return Container(
    color: Theme.of(context).bottomAppBarColor,
    height: 100.0,
    width: double.infinity,
    child: Row(
      mainAxisAlignment: MainAxisAlignment.spaceAround,
      children: <Widget>[
        FutureBuilder(
          future: getLastImage(),
          builder: (context, snapshot) {
            if (snapshot.data == null) {
              return Container(
                width: 40.0,
                height: 40.0,
              );
            }
            return GestureDetector(
              onTap: () => Navigator.push(
                context,
                MaterialPageRoute(
                  builder: (context) => Gallery(),
                ),
              ),
              child: Container(
                width: 40.0,
                height: 40.0,
                child: ClipRRect(
                  borderRadius: BorderRadius.circular(4.0),
                  child: Image.file(
                    snapshot.data,
                    fit: BoxFit.cover,
                  ),
                ),
              ),
            );
          },
        ),
        CircleAvatar(
          backgroundColor: Colors.white,
          radius: 28.0,
          child: IconButton(
            icon: Icon(
              (_isRecordingMode)
                  ? (_isRecording) ? Icons.stop : Icons.videocam
                  : Icons.camera_alt,
              size: 28.0,
              color: (_isRecording) ? Colors.red : Colors.black,
            ),
            onPressed: () {
              if (!_isRecordingMode) {
                _captureImage();
              } else {
                if (_isRecording) {
                  stopVideoRecording();
                } else {
                  startVideoRecording();
                }
              }
            },
          ),
        ),
        IconButton(
          icon: Icon(
            (_isRecordingMode) ? Icons.camera_alt : Icons.videocam,
            color: Colors.white,
          ),
          onPressed: () {
            setState(() {
              _isRecordingMode = !_isRecordingMode;
            });
          },
        ),
      ],
    ),
  );
}

void _captureImage() async {
  if (_controller.value.isInitialized) {
    final Directory extDir = await getApplicationDocumentsDirectory();
    final String dirPath = '${extDir.path}/media';
    await Directory(dirPath).create(recursive: true);
    final String filePath = '$dirPath/${_timestamp()}.jpeg';
    await _controller.takePicture(filePath);
    setState(() {});
  }
}

 
Future<String> startVideoRecording() async {
  print('startVideoRecording');
  if (!_controller.value.isInitialized) {
    return null;
  }
  setState(() {
    _isRecording = true;
  });
  _timerKey.currentState.startTimer();

  final Directory extDir = await getApplicationDocumentsDirectory();
  final String dirPath = '${extDir.path}/media';
  await Directory(dirPath).create(recursive: true);
  final String filePath = '$dirPath/${_timestamp()}.mp4';

  if (_controller.value.isRecordingVideo) {
    // A recording is already started, do nothing.
    return null;
  }

  try {
    await _controller.startVideoRecording(filePath);
  } on CameraException catch (e) {
    _showCameraException(e);
    return null;
  }
  return filePath;
}

 
Future<void> stopVideoRecording() async {
  if (!_controller.value.isRecordingVideo) {
    return null;
  }
  _timerKey.currentState.stopTimer();
  setState(() {
    _isRecording = false;
  });

  try {
    await _controller.stopVideoRecording();
  } on CameraException catch (e) {
    _showCameraException(e);
    return null;
  }
}

 
import 'package:camera/camera.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_camera/gallery.dart';
import 'package:flutter_camera/video_timer.dart';
import 'package:path/path.dart' as path;
import 'package:path_provider/path_provider.dart';
import 'package:thumbnails/thumbnails.dart';

class CameraScreen extends StatefulWidget {
  const CameraScreen({Key key}) : super(key: key);

  @override
  CameraScreenState createState() => CameraScreenState();
}

class CameraScreenState extends State<CameraScreen>
    with AutomaticKeepAliveClientMixin {
  CameraController _controller;
  List<CameraDescription> _cameras;
  final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
  bool _isRecordingMode = false;
  bool _isRecording = false;
  final _timerKey = GlobalKey<VideoTimerState>();

  @override
  void initState() {
    _initCamera();
    super.initState();
  }

  Future<void> _initCamera() async {
    _cameras = await availableCameras();
    _controller = CameraController(_cameras[0], ResolutionPreset.medium);
    _controller.initialize().then((_) {
      if (!mounted) {
        return;
      }
      setState(() {});
    });
  }

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

  @override
  Widget build(BuildContext context) {
    super.build(context);
    if (_controller != null) {
      if (!_controller.value.isInitialized) {
        return Container();
      }
    } else {
      return const Center(
        child: SizedBox(
          width: 32,
          height: 32,
          child: CircularProgressIndicator(),
        ),
      );
    }

    if (!_controller.value.isInitialized) {
      return Container();
    }
    return Scaffold(
      backgroundColor: Theme.of(context).backgroundColor,
      key: _scaffoldKey,
      extendBody: true,
      body: Stack(
        children: <Widget>[
          _buildCameraPreview(),
          Positioned(
            top: 24.0,
            left: 12.0,
            child: IconButton(
              icon: Icon(
                Icons.switch_camera,
                color: Colors.white,
              ),
              onPressed: () {
                _onCameraSwitch();
              },
            ),
          ),
          if (_isRecordingMode)
            Positioned(
              left: 0,
              right: 0,
              top: 32.0,
              child: VideoTimer(
                key: _timerKey,
              ),
            )
        ],
      ),
      bottomNavigationBar: _buildBottomNavigationBar(),
    );
  }

  Widget _buildCameraPreview() {
    final size = MediaQuery.of(context).size;
    return ClipRect(
      child: Container(
        child: Transform.scale(
          scale: _controller.value.aspectRatio / size.aspectRatio,
          child: Center(
            child: AspectRatio(
              aspectRatio: _controller.value.aspectRatio,
              child: CameraPreview(_controller),
            ),
          ),
        ),
      ),
    );
  }

  Widget _buildBottomNavigationBar() {
    return Container(
      color: Theme.of(context).bottomAppBarColor,
      height: 100.0,
      width: double.infinity,
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceAround,
        children: <Widget>[
          FutureBuilder(
            future: getLastImage(),
            builder: (context, snapshot) {
              if (snapshot.data == null) {
                return Container(
                  width: 40.0,
                  height: 40.0,
                );
              }
              return GestureDetector(
                onTap: () => Navigator.push(
                  context,
                  MaterialPageRoute(
                    builder: (context) => Gallery(),
                  ),
                ),
                child: Container(
                  width: 40.0,
                  height: 40.0,
                  child: ClipRRect(
                    borderRadius: BorderRadius.circular(4.0),
                    child: Image.file(
                      snapshot.data,
                      fit: BoxFit.cover,
                    ),
                  ),
                ),
              );
            },
          ),
          CircleAvatar(
            backgroundColor: Colors.white,
            radius: 28.0,
            child: IconButton(
              icon: Icon(
                (_isRecordingMode)
                    ? (_isRecording) ? Icons.stop : Icons.videocam
                    : Icons.camera_alt,
                size: 28.0,
                color: (_isRecording) ? Colors.red : Colors.black,
              ),
              onPressed: () {
                if (!_isRecordingMode) {
                  _captureImage();
                } else {
                  if (_isRecording) {
                    stopVideoRecording();
                  } else {
                    startVideoRecording();
                  }
                }
              },
            ),
          ),
          IconButton(
            icon: Icon(
              (_isRecordingMode) ? Icons.camera_alt : Icons.videocam,
              color: Colors.white,
            ),
            onPressed: () {
              setState(() {
                _isRecordingMode = !_isRecordingMode;
              });
            },
          ),
        ],
      ),
    );
  }

  Future<FileSystemEntity> getLastImage() async {
    final Directory extDir = await getApplicationDocumentsDirectory();
    final String dirPath = '${extDir.path}/media';
    final myDir = Directory(dirPath);
    List<FileSystemEntity> _images;
    _images = myDir.listSync(recursive: true, followLinks: false);
    _images.sort((a, b) {
      return b.path.compareTo(a.path);
    });
    var lastFile = _images[0];
    var extension = path.extension(lastFile.path);
    if (extension == '.jpeg') {
      return lastFile;
    } else {
      String thumb = await Thumbnails.getThumbnail(
          videoFile: lastFile.path, imageType: ThumbFormat.PNG, quality: 30);
      return File(thumb);
    }
  }

  Future<void> _onCameraSwitch() async {
    final CameraDescription cameraDescription =
        (_controller.description == _cameras[0]) ? _cameras[1] : _cameras[0];
    if (_controller != null) {
      await _controller.dispose();
    }
    _controller = CameraController(cameraDescription, ResolutionPreset.medium);
    _controller.addListener(() {
      if (mounted) setState(() {});
      if (_controller.value.hasError) {
        showInSnackBar('Camera error ${_controller.value.errorDescription}');
      }
    });

    try {
      await _controller.initialize();
    } on CameraException catch (e) {
      _showCameraException(e);
    }

    if (mounted) {
      setState(() {});
    }
  }

  void _captureImage() async {
    print('_captureImage');
    if (_controller.value.isInitialized) {
      SystemSound.play(SystemSoundType.click);
      final Directory extDir = await getApplicationDocumentsDirectory();
      final String dirPath = '${extDir.path}/media';
      await Directory(dirPath).create(recursive: true);
      final String filePath = '$dirPath/${_timestamp()}.jpeg';
      print('path: $filePath');
      await _controller.takePicture(filePath);
      setState(() {});
    }
  }

  Future<String> startVideoRecording() async {
    print('startVideoRecording');
    if (!_controller.value.isInitialized) {
      return null;
    }
    setState(() {
      _isRecording = true;
    });
    _timerKey.currentState.startTimer();

    final Directory extDir = await getApplicationDocumentsDirectory();
    final String dirPath = '${extDir.path}/media';
    await Directory(dirPath).create(recursive: true);
    final String filePath = '$dirPath/${_timestamp()}.mp4';

    if (_controller.value.isRecordingVideo) {
      // A recording is already started, do nothing.
      return null;
    }

    try {
//      videoPath = filePath;
      await _controller.startVideoRecording(filePath);
    } on CameraException catch (e) {
      _showCameraException(e);
      return null;
    }
    return filePath;
  }

  Future<void> stopVideoRecording() async {
    if (!_controller.value.isRecordingVideo) {
      return null;
    }
    _timerKey.currentState.stopTimer();
    setState(() {
      _isRecording = false;
    });

    try {
      await _controller.stopVideoRecording();
    } on CameraException catch (e) {
      _showCameraException(e);
      return null;
    }
  }

  String _timestamp() => DateTime.now().millisecondsSinceEpoch.toString();

  void _showCameraException(CameraException e) {
    logError(e.code, e.description);
    showInSnackBar('Error: ${e.code}\n${e.description}');
  }

  void showInSnackBar(String message) {
    _scaffoldKey.currentState.showSnackBar(SnackBar(content: Text(message)));
  }

  void logError(String code, String message) =>
      print('Error: $code\nError Message: $message');

  @override
  bool get wantKeepAlive => true;
}

 
String currentFilePath;
@override
Widget build(BuildContext context) {
  return Scaffold(
    backgroundColor: Theme.of(context).backgroundColor,
    appBar: AppBar(
      backgroundColor: Colors.black,
    ),
    body: FutureBuilder(
      future: _getAllImages(),
      builder: (context, AsyncSnapshot<List<FileSystemEntity>> snapshot) {
        if (!snapshot.hasData || snapshot.data.isEmpty) {
          return Container();
        }
        print('${snapshot.data.length} ${snapshot.data}');
        if (snapshot.data.length == 0) {
          return Center(
            child: Text('No images found.'),
          );
        }

        return PageView.builder(
          itemCount: snapshot.data.length,
          itemBuilder: (context, index) {
            currentFilePath = snapshot.data[index].path;
            var extension = path.extension(snapshot.data[index].path);
            if (extension == '.jpeg') {
              return Container(
                height: 300,
                padding: const EdgeInsets.only(bottom: 8.0),
                child: Image.file(
                  File(snapshot.data[index].path),
                ),
              );
            } else {
              return VideoPreview(
                videoPath: snapshot.data[index].path,
              );
            }
          },
        );
      },
    ),
    bottomNavigationBar: BottomAppBar(
      child: Container(
        height: 56.0,
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
          children: <Widget>[
            IconButton(
              icon: Icon(Icons.share),
              onPressed: () => _shareFile(),
            ),
            IconButton(
              icon: Icon(Icons.delete),
              onPressed: _deleteFile,
            ),
          ],
        ),
      ),
    ),
  );
}

 
Future<List<FileSystemEntity>> _getAllImages() async {
  final Directory extDir = await getApplicationDocumentsDirectory();
  final String dirPath = '${extDir.path}/media';
  final myDir = Directory(dirPath);
  List<FileSystemEntity> _images;
  _images = myDir.listSync(recursive: true, followLinks: false);
  _images.sort((a, b) {
    return b.path.compareTo(a.path);
  });
  return _images;
}

 
_deleteFile() {
  final dir = Directory(currentFilePath);
  dir.deleteSync(recursive: true);
  setState(() {});
}

 
_shareFile() async {
  var extension = path.extension(currentFilePath);
  await Share.file(
    'image',
    (extension == '.jpeg') ? 'image.jpeg' : '  video.mp4',
    File(currentFilePath).readAsBytesSync(),
    (extension == '.jpeg') ? 'image/jpeg' : '  video/mp4',
  );
}