Flutter二维码扫描插件r_scan的使用

r_scan

A flutter plugin about qr code or bar code scan, it can scan from file、url、memory and camera qr code or bar code. Welcome to feedback your issue.

Getting Started

Depend on it

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

dependencies:
  r_scan: last version

Android Platform

Require <code>read storage permission</code> and <code>camera permission</code>, use <code>permission_handler</code> plugin.

import 'package:permission_handler/permission_handler.dart';

Future<bool> canReadStorage() async {
  if (Platform.isIOS) return true;
  var status = await PermissionHandler()
      .checkPermissionStatus(PermissionGroup.storage);
  if (status != PermissionStatus.granted) {
    var future = await PermissionHandler()
        .requestPermissions([PermissionGroup.storage]);
    for (final item in future.entries) {
      if (item.value != PermissionStatus.granted) {
        return false;
      }
    }
  } else {
    return true;
  }
  return true;
}

Future<bool> canOpenCamera() async {
  var status =
      await PermissionHandler().checkPermissionStatus(PermissionGroup.camera);
  if (status != PermissionStatus.granted) {
    var future = await PermissionHandler()
        .requestPermissions([PermissionGroup.camera]);
    for (final item in future.entries) {
      if (item.value != PermissionStatus.granted) {
        return false;
      }
    }
  } else {
    return true;
  }
  return true;
}

IOS Platform

Add the permissions in your Info.plist.

    <key>NSCameraUsageDescription</key>
	<string>扫描二维码时需要使用您的相机</string>
	<key>NSPhotoLibraryUsageDescription</key>
	<string>扫描二维码时需要访问您的相册</string>
	<key>io.flutter.embedded_views_preview</key>
    <true/>

No another.

Usage

1. scan Image File

final result = await RScan.scanImagePath('your file path');

2. scan Image url

final result = await RScan.scanImagePath('your image url');

3. scan Image memory

ByteData data = await rootBundle.load('images/qrCode.png');
final result = await RScan.scanImageMemory(data.buffer.asUint8List());

4. scan camera (new! please upgrade this plugin to v0.14)

Step First: Get available cameras

List<RScanCameraDescription> rScanCameras = await availableRScanCameras();

If you want to get it in main() method, you can use this code.

List<RScanCameraDescription> rScanCameras;

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  rScanCameras = await availableRScanCameras();
  runApp(...);
}

Step Second: Use it.

class RScanCameraDialog extends StatefulWidget {
  [@override](/user/override)
  _RScanCameraDialogState createState() => _RScanCameraDialogState();
}

class _RScanCameraDialogState extends State<RScanCameraDialog> {
  RScanCameraController _controller;
  bool isFirst = true;

  [@override](/user/override)
  void initState() {
    super.initState();
    if (rScanCameras != null && rScanCameras.length > 0) {
      _controller = RScanCameraController(
          rScanCameras[1], RScanCameraResolutionPreset.max)
        ..addListener(() {
          final result = _controller.result;
          if (result != null) {
            if (isFirst) {
              Navigator.of(context).pop(result);
              isFirst = false;
            }
          }
        })
        ..initialize().then((_) {
          if (!mounted) {
            return;
          }
          setState(() {});
        });
    }
  }

  [@override](/user/override)
  void dispose() {
    _controller?.dispose();
    super.dispose();
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    if (rScanCameras == null || rScanCameras.length == 0) {
      return Scaffold(
        body: Container(
          alignment: Alignment.center,
          child: Text('not have available camera'),
        ),
      );
    }
    if (!_controller.value.isInitialized) {
      return Container();
    }
    return Scaffold(
      backgroundColor: Colors.black,
      body: Stack(
        children: <Widget>[
          ScanImageView(
            child: AspectRatio(
              aspectRatio: _controller.value.aspectRatio,
              child: RScanCamera(_controller),
            ),
          ),
          Align(
              alignment: Alignment.bottomCenter,
              child: FutureBuilder(
                future: getFlashMode(),
                builder: _buildFlashBtn,
              ))
        ],
      ),
    );
  }

  Future<bool> getFlashMode() async {
    bool isOpen = false;
    try {
      isOpen = await _controller.getFlashMode();
    } catch (_) {}
    return isOpen;
  }

  Widget _buildFlashBtn(BuildContext context, AsyncSnapshot<bool> snapshot) {
    return snapshot.hasData
        ? Padding(
      padding: EdgeInsets.only(bottom: 24 + MediaQuery.of(context).padding.bottom),
      child: IconButton(
          icon: Icon(snapshot.data ? Icons.flash_on : Icons.flash_off),
          color: Colors.white,
          iconSize: 46,
          onPressed: () {
            if (snapshot.data) {
              _controller.setFlashMode(false);
            } else {
              _controller.setFlashMode(true);
            }
            setState(() {});
          }),
    )
        : Container();
  }
}

5. scan view (Deprecated)

import 'package:flutter/material.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:r_scan/r_scan.dart';

class RScanDialog extends StatefulWidget {
  [@override](/user/override)
  _RScanDialogState createState() => _RScanDialogState();
}

class _RScanDialogState extends State<RScanDialog> {
  RScanController _controller;

  [@override](/user/override)
  void initState() {
    super.initState();
    initController();
  }
  bool isFirst = true;

  Future<void> initController() async {
    _controller = RScanController();
    _controller.addListener(() {
      final result = _controller.result;
      if (result != null) {
        if (isFirst) {
          Navigator.of(context).pop(result);
          isFirst = false;
        }
      }
    });
  }

  [@override](/user/override)
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        backgroundColor: Colors.black,
        body: FutureBuilder<bool>(
          future: canOpenCameraView(),
          builder: (BuildContext context, AsyncSnapshot<bool> snapshot) {
            if (snapshot.hasData && snapshot.data == true) {
              return ScanImageView(
                child: RScanView(
                  controller: _controller,
                ),
              );
            } else {
              return Container();
            }
          },
        ),
      ),
    );
  }

  Future<bool> canOpenCameraView() async {
    var status =
        await PermissionHandler().checkPermissionStatus(PermissionGroup.camera);
    if (status != PermissionStatus.granted) {
      var future = await PermissionHandler()
          .requestPermissions([PermissionGroup.camera]);
      for (final item in future.entries) {
        if (item.value != PermissionStatus.granted) {
          return false;
        }
      }
    } else {
      return true;
    }
    return true;
  }
}

6. open flash lamp / get flash lamp status.

You can use <code>RScanController</code> class.

// turn off the flash lamp.
await _controller.setFlashMode(false);

// turn on the flash lamp.
await _controller.setFlashMode(true);

// get the flash lamp status.
bool isOpen = await _controller.getFlashMode();

7. RScanResult

When you scan finish, will return the RScanResult.

class RScanResult {
  /// barcode type
  final RScanBarType type;

  /// barcode message
  final String message;

  /// barcode points include [x, y]
  final List<RScanPoint> points;
}

Complete Example Demo

import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:image_picker/image_picker.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:r_scan_example/scan_dialog.dart';
import 'scan_camera_dialog.dart';
import 'package:r_scan/r_scan.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  [@override](/user/override)
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyPage(),
    );
  }
}

class MyPage extends StatefulWidget {
  [@override](/user/override)
  _MyPageState createState() => _MyPageState();
}

class _MyPageState extends State<MyPage> {
  RScanResult result;

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('scan example'),
      ),
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        crossAxisAlignment: CrossAxisAlignment.center,
        children: <Widget>[
          Center(
              child: Text(result == null
                  ? '点击下方按钮开始扫码'
                  : '扫码结果${result.toString().split(',').join('\n')}')),
          Center(
            child: FlatButton(
              onPressed: () async {
                final result = await Navigator.of(context).push(
                    MaterialPageRoute(
                        builder: (BuildContext context) => RScanCameraDialog()));
                setState(() {
                  this.result = result;
                });
              },
              child: Text('RScanCamera开始扫码'),
            ),
          ),
          Center(
            child: FlatButton(
              onPressed: () async {
                final result = await Navigator.of(context).push(
                    MaterialPageRoute(
                        builder: (BuildContext context) => RScanDialog()));
                setState(() {
                  this.result = result;
                });
              },
              child: Text('RScanView开始扫码(已弃用)'),
            ),
          ),
          Center(
            child: FlatButton(
              onPressed: () async {
                if (await canReadStorage()) {
                  var image =
                      await ImagePicker.pickImage(source: ImageSource.gallery);
                  if (image != null) {
                    final result = await RScan.scanImagePath(image.path);
                    setState(() {
                      this.result = result;
                    });
                  }
                }
              },
              child: Text('选择图片扫描'),
            ),
          ),
          Center(
            child: FlatButton(
              onPressed: () async {
                final result = await RScan.scanImageUrl(
                    "https://s.cn.bing.net/th?id=OJ.5F0gxqWmxskS0Q&w=75&h=75&pid=MSNJVFeeds");
                setState(() {
                  this.result = result;
                });
              },
              child: Text('网络图片解析'),
            ),
          ),
          Center(
            child: FlatButton(
              onPressed: () async {
                ByteData data = await rootBundle.load('images/qrCode.png');
                final result =
                    await RScan.scanImageMemory(data.buffer.asUint8List());
                setState(() {
                  this.result = result;
                });
              },
              child: Text('内存图片解析'),
            ),
          ),
        ],
      ),
    );
  }

  Future<bool> canReadStorage() async {
    if (Platform.isIOS) return true;
    var status = await PermissionHandler()
        .checkPermissionStatus(PermissionGroup.storage);
    if (status != PermissionStatus.granted) {
      var future = await PermissionHandler()
          .requestPermissions([PermissionGroup.storage]);
      for (final item in future.entries) {
        if (item.value != PermissionStatus.granted) {
          return false;
        }
      }
    } else {
      return true;
    }
    return true;
  }
}