Live Barcode Scanner #

A Flutter package for real-time barcode scanning on iOS and Android. This package provides a customizable barcode scanner with a native camera preview, animated scan line, torch control, and zoom functionality. It supports a variety of barcode formats and streams scan results to your Flutter app via an event channel.

Features #

• Real-Time Scanning: Detects barcodes in real-time using the device’s camera.
• Supported Barcode Formats: EAN-13, EAN-8, PDF417, QR, UPC-E, Code 128, Code 39, Aztec (and more, depending on device capabilities).
• Customizable Scan Frame: Adjust the size of the scan area with a visible border and animated scan line.
• Torch Control: Toggle the camera flash to scan in low-light conditions.
• Zoom Support: Programmatically adjust the camera zoom level.
• Event Streaming: Receive barcode data and error events via Flutter’s EventChannel.
• Cross-Platform: Native implementations for iOS (AVFoundation) and Android (assumed CameraX or equivalent).

Installation #

Add live_barcode_scanner to your pubspec.yaml:

dependencies:
  live_barcode_scanner: ^0.1.0

Run flutter pub get to install the package.

Usage #

Basic Example #

The LiveBarcodeScannerWidget provides a full-screen barcode scanner. Below is a simple example that displays scanned barcodes and handles errors:

import 'package:flutter/material.dart';
import 'package:live_barcode_scanner/live_barcode_scanner.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(home: HomePage());
  }
}

class HomePage extends StatelessWidget {
  HomePage({super.key});
  final controller = LiveBarcodeScannerController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Live Barcode Scanner')),
      body: Column(
        children: [
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            children: [
              ElevatedButton(
                onPressed: () {
                  controller.showBarCodeScanner(context, (result) {
                    debugPrint("Result: $result");
                  }, () {});
                },
                child: Text("Start"),
              ),
            ],
          ),
        ],
      ),
    );
  }
}

Controlling the Scanner #

The package provides a method channel to control the scanner:

• Start Scanning:

  await _methodChannel.invokeMethod('startScan', {'scanFrameSize': 300.0});
  

• Stop Scanning:

  await _methodChannel.invokeMethod('stopScan');
  

• Pause Scanning:

  await _methodChannel.invokeMethod('pauseScan');
  

• Resume Scanning:

  await _methodChannel.invokeMethod('resumeScan');
  

• Toggle Torch:

  await _methodChannel.invokeMethod('toggleTorch');
  

• Set Zoom:

  await _methodChannel.invokeMethod('setZoom', {'zoomFactor': 2.0});
  

Customizing the Scan Frame #

You can adjust the scan frame size by passing scanFrameSize in the creationParams or startScan call:

UiKitView(
  viewType: 'live_barcode_scanner_view',
  creationParams: {'scanFrameSize': 250.0},
  creationParamsCodec: const StandardMessageCodec(),
)

Platform Configuration #

iOS #

1. Add Camera Permission: Update your ios/Runner/Info.plist to include the camera usage description:

   <key>NSCameraUsageDescription</key>
   <string>We need camera access to scan barcodes.</string>
   

2. Minimum iOS Version: Ensure your ios/Podfile specifies at least iOS 13.0:

   platform :ios, '13.0'
   

Android #

1. Add Camera Permission: Update your android/app/src/main/AndroidManifest.xml:

   <uses-permission android:name="android.permission.CAMERA" />
   

2. Request Permission: Ensure your app requests camera permission at runtime. For example, use the permission_handler package:

   import 'package:permission_handler/permission_handler.dart';
   
   Future<void> requestCameraPermission() async {
     var status = await Permission.camera.request();
     if (!status.isGranted) {
       // Handle permission denied
     }
   }
   

3. Minimum SDK: Ensure your android/app/build.gradle specifies at least API 21:

   minSdkVersion 21
   

Troubleshooting #

• Black Screen on iOS:

  • Ensure the UiKitView is wrapped in a Scaffold or SizedBox.expand to provide a non-zero frame.
  • Check Xcode console logs for errors (e.g., INVALID_FRAME, NO_CAMERA).
  • Verify camera permissions are granted and Info.plist is configured.

• Black Screen on Android:

  • Confirm camera permissions are requested and granted.
  • Check Android logs in Android Studio for native errors.

• No Barcodes Detected:

  • Ensure the camera is focused and the barcode is within the scan frame.
  • Verify the barcode type is supported (see supported formats above).

• Errors in Flutter UI:

  • Check the event channel for error events (e.g., PERMISSION_DENIED, SESSION_NOT_RUNNING).
  • Review console logs for detailed error messages.

For detailed debugging, enable verbose logging in your app and check the native logs (Xcode for iOS, Logcat for Android).

Contributing #

Contributions are welcome! Please follow these steps:

1. Fork the repository.
2. Create a feature branch (git checkout -b feature/my-feature).
3. Commit your changes (git commit -m 'Add my feature').
4. Push to the branch (git push origin feature/my-feature).
5. Open a pull request.

Please include tests and update the documentation as needed.

License #

This package is licensed under the MIT License. See the LICENSE file for details.

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