Flutter NFC主机卡模拟插件flutter_nfc_hce的使用

Flutter NFC主机卡模拟插件flutter_nfc_hce的使用

1. 介绍

flutter_nfc_hce 插件项目是在探索跨平台之间使用NFC交换数据的方法过程中发起的。该插件旨在利用Flutter的功能，基于Qifan Yang的NFCAndroid项目中的com.qifan.nfcbank.cardEmulation.KHostApduService实现（参考：NFCAndroid）。关于Android 13版本中与NFC HCE操作相关的问题，参考了MichaelsPlayground/NfcHceNdefEmulator进行了修改。

// KHostApduService.kt
private val READ_CAPABILITY_CONTAINER_RESPONSE = byteArrayOf(
0x00.toByte(), 0x0F.toByte(), // CCLEN 长度为15字节
0x20.toByte(), // 映射版本2.0
0x00.toByte(), 0x3B.toByte(), // MLe 最大值60
0x00.toByte(), 0x34.toByte(), // MLc 最大值52
0x04.toByte(), // NDEF文件控制TLV的T字段
0x06.toByte(), // NDEF文件控制TLV的L字段
0xE1.toByte(), 0x04.toByte(), // NDEF文件标识符
0x00.toByte(), 0xFF.toByte(), // 最大NDEF文件大小为65534字节
0x00.toByte(), // 无需任何安全措施即可读取
0xFF.toByte(), // 无需任何安全措施即可写入
0x90.toByte(), 0x00.toByte(), // A_OKAY
)

NFC HCE操作支持从Android 11到13版本，在当前初始项目中，支持的AID固定为D2760000850101。对于NFC HCE读取器，可以参考使用flutter_manager创建的示例（flutter_nfc_hce_reader）。

2. 截图

主界面	Android NFC HCE

3. 设置

Android设置

1. 在AndroidManifest.xml中添加权限：

   <uses-permission android:name="android.permission.NFC" />
   <uses-feature android:name="android.hardware.nfc" android:required="true" />
   <uses-feature android:name="android.hardware.nfc.hce" android:required="true" />
   <uses-permission android:name="android.permission.VIBRATE" />
   

2. 在AndroidManifest.xml中注册服务：

   <service android:name="com.novice.flutter_nfc_hce.KHostApduService"
            android:exported="true"
            android:enabled="true"
            android:permission="android.permission.BIND_NFC_SERVICE">
       <intent-filter>
           <action android:name="android.nfc.cardemulation.action.HOST_APDU_SERVICE"/>
           <category android:name="android.intent.category.DEFAULT"/>
       </intent-filter>
       <meta-data android:name="android.nfc.cardemulation.host_apdu_service"
                  android:resource="@xml/apduservice"/>
   </service>
   

3. 在res/xml目录下添加apduservice.xml：

   <?xml version="1.0" encoding="utf-8"?>
   <host-apdu-service xmlns:android="http://schemas.android.com/apk/res/android"
                      android:description="@string/servicedesc" 
                      android:requireDeviceScreenOn="false" 
                      android:requireDeviceUnlock="false">
       <aid-group android:description="@string/aiddescription"  android:category="other" >
           <aid-filter android:name="D2760000850101"/>
       </aid-group>
   </host-apdu-service>
   

4. 在res/values目录下添加strings.xml：

   <resources>
       <string name="servicedesc">服务描述</string>
       <string name="aiddescription">AID描述</string>
   </resources>
   

4. 使用示例

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

import 'package:flutter/material.dart';
import 'package:flutter_nfc_hce/flutter_nfc_hce.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> {
  final _flutterNfcHcePlugin = FlutterNfcHce();
  bool _showNFCScanDialog = false;
  var platformVersion;
  bool? isNfcHceSupported;
  bool? isSecureNfcEnabled;
  bool? isNfcEnabled;

  void _getInfo() async {
    platformVersion = await _flutterNfcHcePlugin.getPlatformVersion();
    isNfcHceSupported = await _flutterNfcHcePlugin.isNfcHceSupported();
    isSecureNfcEnabled = await _flutterNfcHcePlugin.isSecureNfcEnabled();
    isNfcEnabled = await _flutterNfcHcePlugin.isNfcEnabled();
  }

  void _onScanButtonPressed() async {
    _getInfo();

    var content = 'flutter_nfc_hce';
    var result = await _flutterNfcHcePlugin.startNfcHce(content, persistMessage: true);

    print('---------------------------------->$result');

    setState(() {
      _showNFCScanDialog = true;
    });
  }

  void _onCloseButtonPressed() async {
    await _flutterNfcHcePlugin.stopNfcHce();

    setState(() {
      _showNFCScanDialog = false;
    });
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Plugin Nfc Hce example app'),
        ),
        body: Container(
          child: Stack(
            children: [
              // 背景Widget
              Container(
                color: Colors.transparent,
                child: Center(
                  child: Column(
                    children: [
                      Text('platformVersion: ${platformVersion ?? ""}'),
                      SizedBox(height: 5),
                      Text('isSupportNfcHceFeature: ${isNfcHceSupported ?? ""}'),
                      SizedBox(height: 5),
                      Text('isSupportSecureNfcSupported: ${isSecureNfcEnabled ?? ""}'),
                      SizedBox(height: 5),
                      Text('isNfcEnagle: ${isNfcEnabled ?? ""}'),
                    ],
                  ),
                ),
              ),

              // NFC扫描对话框
              if (_showNFCScanDialog)
                GestureDetector(
                  onTap: _onCloseButtonPressed,
                  child: Container(
                    color: Colors.black54,
                    alignment: Alignment.center,
                    child: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        Image.asset('assets/nfc_tag.png', width: 100, height: 100),
                        SizedBox(height: 16),
                        Text(
                          'Start Nfc Hce',
                          style: TextStyle(color: Colors.white, fontSize: 18),
                        ),
                      ],
                    ),
                  ),
                ),
            ],
          ),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: _onScanButtonPressed,
          child: Icon(Icons.nfc),
        ),
      ),
    );
  }
}