camera_init.dart

final CameraLensDirection initialCameraLensDirection = CameraLensDirection.back;
static List<CameraDescription> _cameras = [];
int _cameraIndex = -1;

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

    _initialize();
  }

  void _initialize() async {
    if (_cameras.isEmpty) {
      _cameras = await availableCameras();
    }
    for (var i = 0; i < _cameras.length; i++) {
      if (_cameras[i].lensDirection == initialCameraLensDirection) {
        _cameraIndex = i;
        break;
      }
    }
    if (_cameraIndex != -1) {
      _startLiveFeed();
    }
  }

  @override
  void dispose() {
    _stopLiveFeed();
    super.dispose();
  }

  Future _stopLiveFeed() async {
    await _controller?.stopImageStream();
    await _controller?.dispose();
    _controller = null;
  }