A Flutter Plugin for Scanning 2D Barcodes and QRCodes Via Camera

RebornedšŸŽ‰ 

Original barcode_scan was discontinued, so barcode_scan2 was borned with sound null safety supportšŸŽ‰

barcode_scan2 

A flutter plugin for scanning 2D barcodes and QR codes.

This provides a simple wrapper for two commonly used iOS and Android libraries:

Features 

  • Scan 2D barcodes
  • Scan QR codes
  • Control the flash while scanning
  • Permission handling

Getting Started 

Android 

For Android, you must do the following before you can use the plugin:

Add the camera permission to your AndroidManifest.xml

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

This plugin is written in Kotlin. Therefore, you need to add Kotlin support to your project. See installing the Kotlin plugin.

Edit your project-level build.gradle file to look like this:

buildscript {
    ext.kotlin_version = '1.3.61'
    // ...
    dependencies {
        // ...
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}
// ...

Edit your app-level build.gradle file to look like this:

apply plugin: 'kotlin-android'
// ...
dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    // ...
}

Now you can depend on the barcode_scan plugin in your pubspec.yaml file:

dependencies:
    # ...
    barcode_scan2: any

Click "Packages get" in Android Studio or run flutter packages get in your project folder.

iOS 

To use on iOS, you must add the the camera usage description to your Info.plist

<dict>
    <!-- ... -->
    <key>NSCameraUsageDescription</key>
    <string>Camera permission is required for barcode scanning.</string>
    <!-- ... -->
</dict>

Usage 

import 'package:barcode_scan2/barcode_scan2.dart';

void main() async {
  var result = await BarcodeScanner.scan();

  print(result.type); // The result type (barcode, cancelled, failed)
  print(result.rawContent); // The barcode content
  print(result.format); // The barcode format (as enum)
  print(result.formatNote); // If a unknown format was scanned this field contains a note
}

Advanced usage 

You can pass options to the scan method:

import 'package:barcode_scan2/barcode_scan2.dart';

void main() async {

  var options = ScanOptions(
    // set the options
  );

  var result = await BarcodeScanner.scan(options: options);

  // ...
}

Supported options 

OptionTypeDescriptionSupported by
strings.cancelStringThe cancel button text on iOSiOS only
strings.flash_onStringThe flash on button textiOS + Android
strings.flash_offStringThe flash off button textiOS + Android
restrictFormatBarcodeFormat[]Restrict the formats which are recognizediOS + Android
useCameraintThe index of the camera which is used for scanning (See BarcodeScanner.numberOfCameras)iOS + Android
autoEnableFlashboolEnable the flash when start scanningiOS + Android
android.aspectTolerancedoubleEnable auto focus on AndroidAndroid only
android.useAutoFocusboolSet aspect ratio tolerance level used in calculating the optimal Camera preview sizeAndroid only

Development setup 

Setup protobuf 

Mac:

$ brew install protobuf
$ brew install swift-protobuf

Windows / Linux: https://github.com/protocolbuffers/protobuf#protocol-compiler-installation

Activate the protobuf dart plugin:

$ flutter pub global activate protoc_plugin

Install theProtobuf Support plugin for IDEA / Android Studio or vscode-proto3 for VS Code

If you changed the protos.proto you've to execute the ./generate_proto.sh to update the dart / swift sources

Common problems 

Android "Could not find org.jetbrains.kotlin:kotlin-stdlib-jre..." 

Change org.jetbrains.kotlin:kotlin-stdlib-jre to org.jetbrains.kotlin:kotlin-stdlib-jdk (StackOverflow)

Use this package as a library

Depend on it

Run this command:

With Flutter:

 $ flutter pub add barcode_scan2

This will add a line like this to your package's pubspec.yaml (and run an implicit flutter pub get):

dependencies:
  barcode_scan2: ^4.3.0

Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.

Import it

Now in your Dart code, you can use:

import 'package:barcode_scan2/barcode_scan2.dart';

example/lib/main.dart

import 'dart:async';
import 'dart:io' show Platform;

import 'package:barcode_scan2/barcode_scan2.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

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

class App extends StatefulWidget {
  const App({Key? key}) : super(key: key);
  @override
  State<App> createState() => _AppState();
}

class _AppState extends State<App> {
  ScanResult? scanResult;

  final _flashOnController = TextEditingController(text: 'Flash on');
  final _flashOffController = TextEditingController(text: 'Flash off');
  final _cancelController = TextEditingController(text: 'Cancel');

  var _aspectTolerance = 0.00;
  var _numberOfCameras = 0;
  var _selectedCamera = -1;
  var _useAutoFocus = true;
  var _autoEnableFlash = false;

  static final _possibleFormats = BarcodeFormat.values.toList()
    ..removeWhere((e) => e == BarcodeFormat.unknown);

  List<BarcodeFormat> selectedFormats = [..._possibleFormats];

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

    Future.delayed(Duration.zero, () async {
      _numberOfCameras = await BarcodeScanner.numberOfCameras;
      setState(() {});
    });
  }

  @override
  Widget build(BuildContext context) {
    final scanResult = this.scanResult;
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Barcode Scanner Example'),
          actions: [
            IconButton(
              icon: const Icon(Icons.camera),
              tooltip: 'Scan',
              onPressed: _scan,
            ),
          ],
        ),
        body: ListView(
          shrinkWrap: true,
          children: <Widget>[
            if (scanResult != null)
              Card(
                child: Column(
                  children: <Widget>[
                    ListTile(
                      title: const Text('Result Type'),
                      subtitle: Text(scanResult.type.toString()),
                    ),
                    ListTile(
                      title: const Text('Raw Content'),
                      subtitle: Text(scanResult.rawContent),
                    ),
                    ListTile(
                      title: const Text('Format'),
                      subtitle: Text(scanResult.format.toString()),
                    ),
                    ListTile(
                      title: const Text('Format note'),
                      subtitle: Text(scanResult.formatNote),
                    ),
                  ],
                ),
              ),
            const ListTile(
              title: Text('Camera selection'),
              dense: true,
              enabled: false,
            ),
            RadioListTile(
              onChanged: (v) => setState(() => _selectedCamera = -1),
              value: -1,
              title: const Text('Default camera'),
              groupValue: _selectedCamera,
            ),
            ...List.generate(
              _numberOfCameras,
              (i) => RadioListTile(
                onChanged: (v) => setState(() => _selectedCamera = i),
                value: i,
                title: Text('Camera ${i + 1}'),
                groupValue: _selectedCamera,
              ),
            ),
            const ListTile(
              title: Text('Button Texts'),
              dense: true,
              enabled: false,
            ),
            ListTile(
              title: TextField(
                decoration: const InputDecoration(
                  floatingLabelBehavior: FloatingLabelBehavior.always,
                  labelText: 'Flash On',
                ),
                controller: _flashOnController,
              ),
            ),
            ListTile(
              title: TextField(
                decoration: const InputDecoration(
                  floatingLabelBehavior: FloatingLabelBehavior.always,
                  labelText: 'Flash Off',
                ),
                controller: _flashOffController,
              ),
            ),
            ListTile(
              title: TextField(
                decoration: const InputDecoration(
                  floatingLabelBehavior: FloatingLabelBehavior.always,
                  labelText: 'Cancel',
                ),
                controller: _cancelController,
              ),
            ),
            if (Platform.isAndroid) ...[
              const ListTile(
                title: Text('Android specific options'),
                dense: true,
                enabled: false,
              ),
              ListTile(
                title: Text(
                  'Aspect tolerance (${_aspectTolerance.toStringAsFixed(2)})',
                ),
                subtitle: Slider(
                  min: -1,
                  value: _aspectTolerance,
                  onChanged: (value) {
                    setState(() {
                      _aspectTolerance = value;
                    });
                  },
                ),
              ),
              CheckboxListTile(
                title: const Text('Use autofocus'),
                value: _useAutoFocus,
                onChanged: (checked) {
                  setState(() {
                    _useAutoFocus = checked!;
                  });
                },
              ),
            ],
            const ListTile(
              title: Text('Other options'),
              dense: true,
              enabled: false,
            ),
            CheckboxListTile(
              title: const Text('Start with flash'),
              value: _autoEnableFlash,
              onChanged: (checked) {
                setState(() {
                  _autoEnableFlash = checked!;
                });
              },
            ),
            const ListTile(
              title: Text('Barcode formats'),
              dense: true,
              enabled: false,
            ),
            ListTile(
              trailing: Checkbox(
                tristate: true,
                materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
                value: selectedFormats.length == _possibleFormats.length
                    ? true
                    : selectedFormats.isEmpty
                        ? false
                        : null,
                onChanged: (checked) {
                  setState(() {
                    selectedFormats = [
                      if (checked ?? false) ..._possibleFormats,
                    ];
                  });
                },
              ),
              dense: true,
              enabled: false,
              title: const Text('Detect barcode formats'),
              subtitle: const Text(
                'If all are unselected, all possible '
                'platform formats will be used',
              ),
            ),
            ..._possibleFormats.map(
              (format) => CheckboxListTile(
                value: selectedFormats.contains(format),
                onChanged: (i) {
                  setState(
                    () => selectedFormats.contains(format)
                        ? selectedFormats.remove(format)
                        : selectedFormats.add(format),
                  );
                },
                title: Text(format.toString()),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Future<void> _scan() async {
    try {
      final result = await BarcodeScanner.scan(
        options: ScanOptions(
          strings: {
            'cancel': _cancelController.text,
            'flash_on': _flashOnController.text,
            'flash_off': _flashOffController.text,
          },
          restrictFormat: selectedFormats,
          useCamera: _selectedCamera,
          autoEnableFlash: _autoEnableFlash,
          android: AndroidOptions(
            aspectTolerance: _aspectTolerance,
            useAutoFocus: _useAutoFocus,
          ),
        ),
      );
      setState(() => scanResult = result);
    } on PlatformException catch (e) {
      setState(() {
        scanResult = ScanResult(
          rawContent: e.code == BarcodeScanner.cameraAccessDenied
              ? 'The user did not grant the camera permission!'
              : 'Unknown error: $e',
        );
      });
    }
  }
}

Download details:

Author: mono0926.com

Source: https://github.com/mono0926/barcode_scan2

#flutter #android #ios

A Flutter Plugin for Scanning 2D Barcodes and QRCodes Via Camera
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