Flutter二维码扫描插件flutter_acd_scanner的使用

本文档介绍了如何在Flutter应用中使用flutter_acd_scanner插件来连接到ACD扫描器，并获取扫描到的条形码信息。此外，还可以通过该插件向扫描器发送命令。

开始使用

首先，导入Method Channel以发送和接收数据。该通道是一个单例，因此每个设备只有一个实例。

// 监听扫描器传来的数据
MethodChannelAcdScanner().listenOnData.listen((event) {
  log(event);
  data = event;
  setState(() {});
});
// 发送启动扫描的命令
MethodChannelAcdScanner()
    .sendMessage(what: MethodChannelAcdScanner.WHAT_SCAN);

发送预定义事件

你可以发送各种预定义的事件，如激活或取消扫描、启用或禁用扫描键和光束等：

[@override](/user/override)
Future<String> activateScan() async {
  // 启动扫描
  return sendMessage(what: MethodChannelAcdScanner.WHAT_SCAN, arg1: 1);
}

[@override](/user/override)
Future<String> deactivateScan() async {
  // 停止扫描
  return sendMessage(what: MethodChannelAcdScanner.WHAT_SCAN, arg1: 0);
}

[@override](/user/override)
Future<String> enableScanKey() async {
  // 启用扫描键
  return sendMessage(what: MethodChannelAcdScanner.WHAT_KEY_ENABLE, arg1: 1);
}

[@override](/user/override)
Future<String> disableScanKey() async {
  // 禁用扫描键
  return sendMessage(what: MethodChannelAcdScanner.WHAT_KEY_ENABLE, arg1: 0);
}

[@override](/user/override)
Future<String> enableScanBeam() async {
  // 启用扫描光束
  return sendMessage(what: MethodChannelAcdScanner.WHAT_BEAM, arg1: 1);
}

[@override](/user/override)
Future<String> disableScanBeam() async {
  // 禁用扫描光束
  return sendMessage(what: MethodChannelAcdScanner.WHAT_BEAM, arg1: 0);
}

发送自定义消息

你也可以发送自定义的消息：

[@override](/user/override)
Future<String> sendMessage({required int what, int? arg1, int? arg2}) async {
  // 构建参数
  Map<String, int> params = {'what': what, 'arg1': arg1 ?? 0, 'arg2': arg2 ?? 0};
  // 调用方法通道发送消息
  return await methodChannel.invokeMethod('sendMessage', params);
}

完整示例

以下是一个完整的示例代码，展示了如何使用flutter_acd_scanner插件：

import 'dart:async';
import 'dart:developer';

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

void main() {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  [@override](/user/override)
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String data = "";

  [@override](/user/override)
  void initState() {
    super.initState();
    initPlatformState();
  }

  // 初始化平台状态
  Future<void> initPlatformState() async {
    // 初始化监听
    try {
      MethodChannelAcdScanner().listenOnData.listen((event) {
        log(event);
        data = event;
        setState(() {});
      });
      // 发送启动扫描的命令
      MethodChannelAcdScanner()
          .sendMessage(what: MethodChannelAcdScanner.WHAT_SCAN);
    } on PlatformException {}

    // 如果小部件从树中被移除，则返回
    if (!mounted) return;
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Plugin example app'),
        ),
        body: Center(
          child: Text('Scanner Intent Started: $data\n'),
        ),
      ),
    );
  }
}