ente_qr

A Flutter plugin for scanning QR codes from image files. This plugin provides a simple interface to scan QR codes from images on both Android and iOS platforms.

Features

• Scan QR codes from image files
• Support for Android (using ZXing library)
• Support for iOS (using AVFoundation/Core Image)
• Returns structured results with error handling
• Works with images from file picker or camera

Platform Support

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  ente_qr:
    path: path/to/ente_qr

Usage

Basic Usage

import 'package:ente_qr/ente_qr.dart';

final qr = EnteQr();

// Scan QR code from an image file
final result = await qr.scanQrFromImage('/path/to/image.jpg');

if (result.success) {
  print('QR Code content: ${result.content}');
} else {
  print('Error: ${result.error}');
}

Complete Example with File Picker

import 'package:flutter/material.dart';
import 'package:ente_qr/ente_qr.dart';
import 'package:file_picker/file_picker.dart';

class QrScannerPage extends StatefulWidget {
  @override
  _QrScannerPageState createState() => _QrScannerPageState();
}

class _QrScannerPageState extends State<QrScannerPage> {
  final _enteQr = EnteQr();
  String _result = 'No QR code scanned';

  Future<void> _scanQrFromImage() async {
    // Pick an image file
    FilePickerResult? fileResult = await FilePicker.platform.pickFiles(
      type: FileType.image,
      allowMultiple: false,
    );

    if (fileResult != null && fileResult.files.single.path != null) {
      final imagePath = fileResult.files.single.path!;
      
      // Scan QR code from the selected image
      final qrResult = await _enteQr.scanQrFromImage(imagePath);
      
      setState(() {
        if (qrResult.success) {
          _result = 'QR Code: ${qrResult.content}';
        } else {
          _result = 'Error: ${qrResult.error}';
        }
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('QR Scanner')),
      body: Column(
        children: [
          ElevatedButton(
            onPressed: _scanQrFromImage,
            child: Text('Pick Image and Scan QR'),
          ),
          Text(_result),
        ],
      ),
    );
  }
}

API Reference

EnteQr

The main class for QR code scanning operations.

Methods

scanQrFromImage(String imagePath)

Scans a QR code from an image file.

Parameters:

• imagePath (String): The file path to the image containing the QR code

Returns:

• Future<QrScanResult>: A result object containing either the QR code content or an error

QrScanResult

The result object returned by QR scanning operations.

Properties:

• content (String?): The QR code content if successful, null otherwise
• error (String?): Error message if scanning failed, null otherwise
• success (bool): Whether the scanning operation was successful

Factory Constructors:

• QrScanResult.success(String content): Creates a successful result
• QrScanResult.error(String error): Creates an error result

Implementation Details

Android

The Android implementation uses the ZXing library (com.google.zxing) for QR code detection:

• com.journeyapps:zxing-android-embedded:4.3.0
• com.google.zxing:core:3.5.1

iOS

The iOS implementation uses Core Image framework's built-in QR code detection capabilities via CIDetector.

Error Handling

The plugin provides comprehensive error handling for common scenarios:

• File not found
• Invalid image format
• No QR code found in image
• Platform-specific errors
• Unexpected errors

All errors are returned as part of the QrScanResult object with descriptive error messages.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the same license as the Ente project.