[Flutter] 플러터 QR 코드 스캔 구현 qr_code_scanner 사용법

2023-12-14

 

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사진: Unsplash 의 Tobias Rademacher

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1. 준비

 

아래의 정보들을 각 위치에 맞게 추가한다.

 

pubspec.yaml 

 

dependencies:
  qr_code_scanner: ^1.0.1

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android

 

아래는 자신의 android gradle 설정 정보를 확인 하는 것이 필요하다.

 

In android/build.gradle change ext.kotlin_version = '1.3.50' to ext.kotlin_version = '1.5.10'
(코틀린 버전 변경필요)
In android/build.gradle change classpath 'com.android.tools.build:gradle:3.5.0' to classpath 'com.android.tools.build:gradle:4.2.0'
(gradle 버전 변경필요)
In android/gradle/wrapper/gradle-wrapper.properties change distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip to distributionUrl=https\://services.gradle.org/distributions/gradle-6.9-all.zip
(gradle wrapper 설정정보 변경 필요)
In android/app/build.gradle change defaultConfig{ ... minSdkVersion 16 } to defaultConfig{ ... minSdkVersion 20 }
(최소 sdk 버전 업글 필요)

 

your_app/android/app/src/main/AndroidManifest.xml 에 추가

 

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

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ios (Info.plist file)

 

<key>io.flutter.embedded_views_preview</key>
<true/>
<key>NSCameraUsageDescription</key>
<string>This app needs camera access to scan QR codes</string>

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2. 구현코드

 

아래에 전체코드 중 실제 사용하는 중요한 부분만 설명하겠다. 아래코드는 qr 코드 스캔결과 즉 result 값이 있을 경우에 동작하는 부분이다.

여기서 나오는 result.code의 값이 큐알코드에 있는 url 값이 되며 이후 해당 부분을 활용해 링크를 활용해 http 요청을 보낸다든지 아니면 웹뷰로 전향하든지 커스텀해서 자신의 앱에 맞게 사용하면 된다.

 

...
children: <Widget>[
	if (result != null)
		Text(
    		'Barcode Type: ${describeEnum(result!.format)}   Data: ${result!.code}')
	else
		const Text('Scan a code'),
...

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해당 부분은 실제 큐알코드 인식하는 부분을 랜더링 하는 부분으로 기본적인 큐알인식 크기 또는 인식하는 부분의 기본적인 ui 를 설정하면 운영체제에 따른 권한을 확인하는 코드이다. 

 

 Widget _buildQrView(BuildContext context) {
    // For this example we check how width or tall the device is and change the scanArea and overlay accordingly.
    var scanArea = (MediaQuery.of(context).size.width < 400 ||
            MediaQuery.of(context).size.height < 400)
        ? 150.0
        : 300.0;
    // To ensure the Scanner view is properly sizes after rotation
    // we need to listen for Flutter SizeChanged notification and update controller
    return QRView(
      key: qrKey,
      onQRViewCreated: _onQRViewCreated,
      overlay: QrScannerOverlayShape(
          borderColor: Colors.red,
          borderRadius: 10,
          borderLength: 30,
          borderWidth: 10,
          cutOutSize: scanArea),
      onPermissionSet: (ctrl, p) => _onPermissionSet(context, ctrl, p),
    );
  }

  void _onQRViewCreated(QRViewController controller) {
    setState(() {
      this.controller = controller;
    });
    controller.scannedDataStream.listen((scanData) {
      setState(() {
        result = scanData;
      });
    });
  }

  void _onPermissionSet(BuildContext context, QRViewController ctrl, bool p) {
    log('${DateTime.now().toIso8601String()}_onPermissionSet $p');
    if (!p) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('no Permission')),
      );
    }
  }

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전체코드

 

import 'dart:developer';
import 'dart:io';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:qr_code_scanner/qr_code_scanner.dart';

void main() => runApp(const MaterialApp(home: MyHome()));

class MyHome extends StatelessWidget {
  const MyHome({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Flutter Demo Home Page')),
      body: Center(
        child: ElevatedButton(
          onPressed: () {
            Navigator.of(context).push(MaterialPageRoute(
              builder: (context) => const QRViewExample(),
            ));
          },
          child: const Text('qrView'),
        ),
      ),
    );
  }
}

class QRViewExample extends StatefulWidget {
  const QRViewExample({Key? key}) : super(key: key);

  @override
  State<StatefulWidget> createState() => _QRViewExampleState();
}

class _QRViewExampleState extends State<QRViewExample> {
  Barcode? result;
  QRViewController? controller;
  final GlobalKey qrKey = GlobalKey(debugLabel: 'QR');

  // In order to get hot reload to work we need to pause the camera if the platform
  // is android, or resume the camera if the platform is iOS.
  @override
  void reassemble() {
    super.reassemble();
    if (Platform.isAndroid) {
      controller!.pauseCamera();
    }
    controller!.resumeCamera();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        children: <Widget>[
          Expanded(flex: 4, child: _buildQrView(context)),
          Expanded(
            flex: 1,
            child: FittedBox(
              fit: BoxFit.contain,
              child: Column(
                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                children: <Widget>[
                  if (result != null)
                    Text(
                        'Barcode Type: ${describeEnum(result!.format)}   Data: ${result!.code}')
                  else
                    const Text('Scan a code'),
                  Row(
                    mainAxisAlignment: MainAxisAlignment.center,
                    crossAxisAlignment: CrossAxisAlignment.center,
                    children: <Widget>[
                      Container(
                        margin: const EdgeInsets.all(8),
                        child: ElevatedButton(
                            onPressed: () async {
                              await controller?.toggleFlash();
                              setState(() {});
                            },
                            child: FutureBuilder(
                              future: controller?.getFlashStatus(),
                              builder: (context, snapshot) {
                                return Text('Flash: ${snapshot.data}');
                              },
                            )),
                      ),
                      Container(
                        margin: const EdgeInsets.all(8),
                        child: ElevatedButton(
                            onPressed: () async {
                              await controller?.flipCamera();
                              setState(() {});
                            },
                            child: FutureBuilder(
                              future: controller?.getCameraInfo(),
                              builder: (context, snapshot) {
                                if (snapshot.data != null) {
                                  return Text(
                                      'Camera facing ${describeEnum(snapshot.data!)}');
                                } else {
                                  return const Text('loading');
                                }
                              },
                            )),
                      )
                    ],
                  ),
                  Row(
                    mainAxisAlignment: MainAxisAlignment.center,
                    crossAxisAlignment: CrossAxisAlignment.center,
                    children: <Widget>[
                      Container(
                        margin: const EdgeInsets.all(8),
                        child: ElevatedButton(
                          onPressed: () async {
                            await controller?.pauseCamera();
                          },
                          child: const Text('pause',
                              style: TextStyle(fontSize: 20)),
                        ),
                      ),
                      Container(
                        margin: const EdgeInsets.all(8),
                        child: ElevatedButton(
                          onPressed: () async {
                            await controller?.resumeCamera();
                          },
                          child: const Text('resume',
                              style: TextStyle(fontSize: 20)),
                        ),
                      )
                    ],
                  ),
                ],
              ),
            ),
          )
        ],
      ),
    );
  }

  Widget _buildQrView(BuildContext context) {
    // For this example we check how width or tall the device is and change the scanArea and overlay accordingly.
    var scanArea = (MediaQuery.of(context).size.width < 400 ||
            MediaQuery.of(context).size.height < 400)
        ? 150.0
        : 300.0;
    // To ensure the Scanner view is properly sizes after rotation
    // we need to listen for Flutter SizeChanged notification and update controller
    return QRView(
      key: qrKey,
      onQRViewCreated: _onQRViewCreated,
      overlay: QrScannerOverlayShape(
          borderColor: Colors.red,
          borderRadius: 10,
          borderLength: 30,
          borderWidth: 10,
          cutOutSize: scanArea),
      onPermissionSet: (ctrl, p) => _onPermissionSet(context, ctrl, p),
    );
  }

  void _onQRViewCreated(QRViewController controller) {
    setState(() {
      this.controller = controller;
    });
    controller.scannedDataStream.listen((scanData) {
      setState(() {
        result = scanData;
      });
    });
  }

  void _onPermissionSet(BuildContext context, QRViewController ctrl, bool p) {
    log('${DateTime.now().toIso8601String()}_onPermissionSet $p');
    if (!p) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('no Permission')),
      );
    }
  }

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

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3. 출처

 

https://pub.dev/packages/qr_code_scanner/install

qr_code_scanner | Flutter Package

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메인 이미지 출처 : 사진: Unsplash의Tobias Rademacher