Flutter自制插件之r_scan二维码&条形码扫描（支持文件

2020-02-27 本文已影响0人 rhyme_lph

image

介绍

二维码作为信息的载体，广泛应用于我们生活的方方面面，例如：使用支付宝支付，二维码加好友，二维码推广等等，能举例的例子多不胜数，而如果你的应用支持二维码的扫描，用户和体验将会翻倍的增长，如果你是应用的开发者，欢迎来使用此二维码扫描插件！并希望能给予项目一个star，谢谢！项目地址：https://github.com/rhymelph/r_scan

使用

你可以在pub.dev网站上面搜索r_scan即可找到该插件，添加下面代码到pubspec.yaml文件

dependencies:
    r_scan: last version

last version 可以在pub.dev网站搜索r_scan得到

各设备注意事项

Android平台下

android6.0系统以上请动态授权，可以结合permission_handler插件使用，代码如下：

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平台下

需要在info.plist文件下添加如下代码：

    <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/>

导包

import 'package:r_scan/r_scan.dart';

1.扫描文件图片二维码

final result=await RScan.scanImagePath('你的文件路径');
if(result.isNotEmpty){
    //result 为二维码内容
}

2.扫描图片链接二维码

final result=await RScan.scanImagePath('你的图片链接');
if(result.isNotEmpty){
    //result 为二维码内容
}

3.扫描内存图片二维码

ByteData data=await rootBundle.load('images/qrCode.png');
final result=await RScan.scanImageMemory(data.buffer.asUint8List());
if(result.isNotEmpty){
    //result 为二维码内容
}

4.(NEW)基于Texture使用相机扫描二维码/条形码

步骤1:获取可用相机

List<RScanCameraDescription> rScanCameras = await availableRScanCameras();;

如果你在main()方法下获取可用相机，请使用下面代码

List<RScanCameraDescription> rScanCameras;

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

步骤2:开始使用

class RScanCameraDialog extends StatefulWidget {
  @override
  _RScanCameraDialogState createState() => _RScanCameraDialogState();
}

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

  @override
  void initState() {
    super.initState();
    //判断当前是否有可用相机
    if (rScanCameras != null && rScanCameras.length > 0) {
    //初始化相机控制器，一般rScanCameras[0]为后置，rScanCameras[1]为前置摄像头
      _controller = RScanCameraController(
          rScanCameras[0], RScanCameraResolutionPreset.max)
        ..addListener(() {
        //监听扫码返回结果
          final result = _controller.result;
          if (result != null) {
            if (isFirst) {
            //如果扫描到二维码将结果返回到上一页
              Navigator.of(context).pop(result);
              isFirst = false;
            }
          }
        })
        ..initialize().then((_) {
        //初始化相机
          if (!mounted) {
            return;
          }
          setState(() {});
        });
    }
  }

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

  @override
  Widget build(BuildContext context) {
  //判断是否有可用相机
    if (rScanCameras == null || rScanCameras.length == 0) {
      return Scaffold(
        body: Container(
          alignment: Alignment.center,
          child: Text('not have available camera'),
        ),
      );
    }
    //判断相机如果没有初始化，给它一个加载页面
    if (!_controller.value.isInitialized) {
      return Container();
    }
    //获取到相机
    return Scaffold(
      backgroundColor: Colors.black,
      body: Stack(
        children: <Widget>[
          ScanImageView(
            child: AspectRatio(
            //拿到相机的aspectRatio
              aspectRatio: _controller.value.aspectRatio,
              child: RScanCamera(_controller),
            ),
          ),
          //闪光灯
          Align(
              alignment: Alignment.bottomCenter,
              child: FutureBuilder(
                future: getFlashMode(),
                builder: _buildFlashBtn,
              ))
        ],
      ),
    );
  }
  //获取闪光灯是否打开
  Future<bool> getFlashMode() async {
    bool isOpen = false;
    try {
      isOpen = await _controller.getFlashMode();
    } catch (_) {}
    return isOpen;
  }

//构建闪光灯按钮
  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.(已弃用)基于PlatformView使用相机扫描二维码/条形码

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

class RScanDialog extends StatefulWidget {
  @override
  _RScanDialogState createState() => _RScanDialogState();
}

class _RScanDialogState extends State<RScanDialog> {
  RScanController _controller;

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


  Future<void> initController() async {
    _controller = RScanController();
    _controller.addListener(() {//监听扫描到的二维码
      final result = _controller.result;
      if (result != null) {
        if(isFirst){
          Navigator.of(context).pop(result);
          isFirst=false;
        }
      }
    });
  }

  @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(//这个为自己写的前景
                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. 打开闪光灯/获取闪光灯状态

使用RScanController类的实例直接调用

//关闭闪光灯
await _controller.setFlashMode(false);

//打开闪光灯
await _controller.setFlashMode(true);

// 获取闪光灯状态
bool isOpen = await _controller.getFlashMode();

7.RScanResult(二维码扫描结果)

当扫描到二维码&条形码将返回该对象，包含如下内容

class RScanResult {
  /// 条形码类型
  final RScanBarType type;

  ///附带的信息
  final String message;

  ///条形码对应的区域 包含 [x , y] 坐标
  final List<RScanPoint> points;
}

后续开发

支持自定义区域触发扫描
还有更多...