qr_code.dart

import 'package:camera/camera.dart';
import 'package:flutter/material.dart';
import 'package:flutter_modular/flutter_modular.dart';
import 'package:google_ml_kit/google_ml_kit.dart';
import 'qrcode_controller.dart';

class QrcodePage extends StatefulWidget {
  final String title;
  const QrcodePage({Key key, this.title = "Qrcode"}) : super(key: key);

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

class _QrcodePageState extends ModularState<QrcodePage, QrcodeController> {
  //use 'controller' variable to access controller
  List<CameraDescription> cameras;

  CameraController controllerCamera;
  final barcodeDetector = GoogleMlKit.vision.barcodeScanner();

  int camSelect = 0;
  bool isReader = false;

  @override
  void initState() {
    super.initState();
    availableCameras().then((cams) {
      cameras = cams;
      _initCam(0);
    });
  }

  InputImagePlaneMetadata _convertPlaneToInputImagePlaneMetadata(Plane e) {
    return InputImagePlaneMetadata(bytesPerRow: e.bytesPerRow, height: e.height, width: e.width);
  }

  _takePhotoAndRecognizer(CameraImage image) async {
    try {
      if (!(controllerCamera?.value?.isInitialized == true) && isReader) return;

      final size = Size(image.width.toDouble(), image.height.toDouble());

      final data = InputImageData(
        planeData: image.planes.map(_convertPlaneToInputImagePlaneMetadata).toList(),
        size: size,
        imageRotation: InputImageRotation.Rotation_0deg,
      );

      final inputImage = InputImage.fromBytes(bytes: image.planes[0].bytes, inputImageData: data);
      final barcodes = await barcodeDetector.processImage(inputImage);
      if (barcodes.isNotEmpty) {
        isReader = true;
        await controllerCamera.stopImageStream();
        Navigator.of(context).pop(barcodes[0].info.rawValue);
      }
    } on Exception catch (e) {
      print(e);
    }
  }

  _initCam(int cam) {
    camSelect = cam;
    controllerCamera = CameraController(cameras[cam], ResolutionPreset.high);
    controllerCamera.initialize().then((_) {
      if (!mounted) {
        return;
      }
      setState(() {});
      controllerCamera.startImageStream(_takePhotoAndRecognizer);
    });
  }

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

  _changeCamera() async {
    if (cameras.length > 1) {
      await controllerCamera?.dispose();
      _initCam(camSelect == 0 ? 1 : 0);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.black,
      body: Builder(builder: (_) {
        final cameraIsReady = controllerCamera?.value?.isInitialized == true;

        return Stack(
          children: [
            if (!cameraIsReady) Container(color: Colors.grey[700]),
            if (cameraIsReady)
              Container(
                height: MediaQuery.of(context).size.height,
                width: MediaQuery.of(context).size.width,
                child: FittedBox(
                  fit: BoxFit.cover,
                  alignment: Alignment.center,
                  child: Container(
                    alignment: Alignment.center,
                    width: controllerCamera.value.previewSize.width,
                    height: controllerCamera.value.previewSize.height,
                    child: CameraPreview(controllerCamera),
                  ),
                ),
              ),
            Align(
              alignment: Alignment.center,
              child: _Mask(),
            ),
            Align(
              alignment: Alignment.bottomCenter,
              child: Container(
                color: Colors.black,
                width: double.infinity,
                height: MediaQuery.of(context).size.height * 0.1,
                alignment: Alignment.center,
                child: IconButton(
                  color: Colors.white,
                  iconSize: 30,
                  icon: Icon(camSelect == 0 ? Icons.camera_rear : Icons.camera_front),
                  onPressed: _changeCamera,
                ),
              ),
            ),
            Align(
              alignment: Alignment.topLeft,
              child: SafeArea(
                child: Padding(
                  padding: EdgeInsets.only(top: 10, left: 10),
                  child: BackButton(
                    color: Colors.white,
                  ),
                ),
              ),
            ),
          ],
        );
      }),
    );
  }
}

class _Mask extends StatelessWidget {
  final Color colorMask = Colors.black45;

  @override
  Widget build(BuildContext context) {
    final size = MediaQuery.of(context).size.width * 0.85;
    return Column(
      children: [
        Expanded(child: Container(color: colorMask)),
        SizedBox(
          width: MediaQuery.of(context).size.width,
          height: size,
          child: Row(
            children: [
              Expanded(child: Container(color: colorMask)),
              HardLine(size: size),
              Expanded(child: Container(color: colorMask)),
            ],
          ),
        ),
        Expanded(child: Container(color: colorMask)),
        SizedBox(height: MediaQuery.of(context).size.height * 0.1),
      ],
    );
  }
}

class HardLine extends StatefulWidget {
  final double size;

  const HardLine({Key key, @required this.size}) : super(key: key);

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

class _HardLineState extends State<HardLine> with SingleTickerProviderStateMixin {
  AnimationController animationController;

  @override
  void initState() {
    super.initState();
    animationController = AnimationController(vsync: this, duration: Duration(seconds: 2));
    animationController.addListener(() {
      setState(() {});
    });

    animationController.repeat(reverse: true);
  }

  @override
  void dispose() {
    super.dispose();
    animationController.stop();
    animationController.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      height: widget.size,
      width: widget.size,
      child: Stack(
        children: [
          Transform.translate(
            offset: Offset(0.0, widget.size * animationController.value),
            child: Container(
              width: widget.size,
              height: 3,
              color: Colors.red,
            ),
          )
        ],
      ),
    );
  }
}