当然，下面是一个关于如何在Flutter项目中使用google_mlkit_barcode_scanning插件进行条形码扫描的示例代码。这个示例包括如何设置插件、打开相机进行条形码扫描以及处理扫描结果。

1. 添加依赖

首先，你需要在pubspec.yaml文件中添加google_mlkit_barcode_scanning依赖：

dependencies:
  flutter:
    sdk: flutter
  google_mlkit_barcode_scanning: ^0.18.0  # 请检查最新版本号

然后运行flutter pub get来安装依赖。

2. 配置Android权限

在android/app/src/main/AndroidManifest.xml中添加相机权限：

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />

3. 创建条形码扫描页面

接下来，创建一个新的Flutter页面用于条形码扫描。以下是一个简单的示例：

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

class BarcodeScannerPage extends StatefulWidget {
  @override
  _BarcodeScannerPageState createState() => _BarcodeScannerPageState();
}

class _BarcodeScannerPageState extends State<BarcodeScannerPage> {
  late List<CameraDescription> cameras;
  late CameraController? controller;
  final BarcodeScannerOptions options = BarcodeScannerOptions(
    beepOnScan: true,
    useFrontCamera: false,
    tryHarder: true,
    torchEnabled: false,
    autoFocusMode: AutoFocusMode.continuous,
  );
  BarcodeScanner? scanner;
  String? resultText;

  @override
  void initState() {
    super.initState();
    availableCameras().then((availableCameras) {
      cameras = availableCameras;
      if (cameras.isEmpty) {
        return;
      }
      controller = new CameraController(
        cameras[0],
        ResolutionPreset.high,
        enableAudio: true,
      );
      controller!.initialize().then((_) {
        if (mounted) {
          setState(() {});
        }
        scanner = GoogleMlKitBarcodeScanner(options: options);
        controller!.startImageStream((CameraImage image) async {
          final inputImage = InputImage.fromBytes(
            bytes: image.planes.map((plane) {
              return plane.bytes;
            }).reduce((value, element) => value + element.lengthInBytes),
            size: Size(image.width, image.height),
            format: image.format.raw,
            planeData: image.planes.map((plane) {
              return InputImagePlaneMetadata(
                bytesPerRow: plane.bytesPerRow,
                height: plane.height,
                width: plane.width,
              );
            }).toList(),
          );
          try {
            final result = await scanner!.scanBarcodes(inputImage);
            if (result.isNotEmpty && mounted) {
              setState(() {
                resultText = result[0].rawValue;
              });
              // 停止相机流并处理结果
              controller!.stopImageStream();
              Navigator.pop(context, resultText);
            }
          } catch (e) {
            print(e);
          }
        });
      }).catchError((error) {
        print("Error: ${error.message}");
      });
    }).catchError((error) {
      print("Error: ${error.message}");
    });
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Barcode Scanner'),
      ),
      body: cameras.isEmpty
          ? Center(
              child: Text(
                'No cameras found!',
                style: TextStyle(color: Colors.red),
              ))
          : AspectRatio(
              aspectRatio: controller!.value.aspectRatio,
              child: CameraPreview(controller!)),
      floatingActionButton: FloatingActionButton(
        onPressed: () async {
          if (!controller!.value.isStreamingImages) {
            await controller!.startImageStream((CameraImage image) async {
              // This will be called when an image is available from the camera.
            });
          } else {
            await controller!.stopImageStream();
          }
        },
        tooltip:
            'Start/Stop camera preview',
        child: Icon(controller!.value.isStreamingImages ? Icons.stop : Icons.play_arrow),
      ),
      floatingActionButtonLocation: FloatingActionButtonLocation.centerFloat,
      bottomSheet: resultText != null
          ? Container(
              padding: EdgeInsets.all(16.0),
              color: Colors.white,
              child: Center(
                child: Text(
                  'Scanned Barcode: $resultText',
                  style: TextStyle(fontSize: 20),
                ),
              ))
          : null,
    );
  }
}

4. 使用条形码扫描页面

在你的主应用代码中，导航到BarcodeScannerPage：

import 'package:flutter/material.dart';
import 'barcode_scanner_page.dart';  // 假设你保存上面的代码到这个文件

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Flutter Barcode Scanner'),
        ),
        body: Center(
          child: ElevatedButton(
            onPressed: () {
              Navigator.push(
                context,
                MaterialPageRoute(builder: (context) => BarcodeScannerPage()),
              );
            },
            child: Text('Scan Barcode'),
          ),
        ),
      ),
    );
  }
}

这个示例代码展示了如何使用google_mlkit_barcode_scanning插件来扫描条形码。注意，在实际应用中，你可能需要添加更多的错误处理和UI优化。