Flutter USB通信插件ledger_usb的使用
Flutter USB通信插件ledger_usb的使用
介绍
ledger_usb 插件允许 Flutter 应用程序通过 USB 连接与 Ledger 硬件钱包进行通信。该插件提供了与 Ledger 设备进行交互的功能，例如列出设备、请求权限、打开连接、交换数据等。
完整示例
以下是一个完整的示例，展示了如何使用 ledger_usb 插件与 Ledger 设备进行通信。
import 'package:algorand_dart/algorand_dart.dart';
import 'package:flutter/material.dart';
import 'package:ledger_algorand/ledger_algorand.dart';
import 'package:ledger_flutter/ledger.dart';
import 'package:ledger_usb/ledger_usb.dart';
import 'package:ledger_usb/usb_device.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatefulWidget {
const MyApp({super.key});
@override
State<MyApp> createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
final _ledgerUsbPlugin = LedgerUsb();
UsbDevice? device;
final Algorand algorand = Algorand(
algodClient: AlgodClient(
apiUrl: AlgoExplorer.MAINNET_ALGOD_API_URL,
),
);
@override
void initState() {
super.initState();
}
Future<RawTransaction> _buildTransaction({required Address account}) async {
final tx = await algorand.createPaymentTransaction(
sender: account,
receiver: account,
amount: Algo.toMicroAlgos(1),
);
return tx;
}
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: const Text('Plugin example app'),
),
body: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
TextButton(
child: const Text('List devices'),
onPressed: () async {
final devices = await _ledgerUsbPlugin.listDevices();
if (devices.isEmpty) {
return;
}
setState(() {
device = devices.first;
});
},
),
TextButton(
onPressed: device != null
? () async {
await _ledgerUsbPlugin.requestPermission(device!);
}
: null,
child: const Text('Request permission'),
),
TextButton(
onPressed: device != null
? () async {
await _ledgerUsbPlugin.open(device!);
}
: null,
child: const Text('Connect'),
),
TextButton(
onPressed: device != null
? () async {
final address = Address.fromAlgorandAddress(
'BYPEBY4EFT4M7GV4N34CMTFDQHHVEX27W5Y36UGCGS7HHA7VBDOEOQXCYM');
final tx = await _buildTransaction(account: address);
final operation = AlgorandSignMsgPackOperation(
accountIndex: 1,
transaction: tx.toBytes(),
);
final writer = ByteDataWriter();
final apdu = await operation.write(writer);
final response = await _ledgerUsbPlugin.exchange(
apdu,
timeout: 2000,
);
final reader = ByteDataReader();
reader.add(response.expand((e) => e).toList());
final signature = await operation.read(reader);
final signedTx = SignedTransaction(
transaction: tx,
signature: signature,
);
signedTx.authAddress = address;
try {
final txId = await algorand.sendTransaction(
signedTx,
waitForConfirmation: true,
);
debugPrint(txId);
debugPrint(signedTx.transactionId);
} on AlgorandException catch (ex) {
debugPrint(ex.message);
}
}
: null,
child: const Text('Exchange'),
),
TextButton(
onPressed: device != null
? () async {
await _ledgerUsbPlugin.close();
}
: null,
child: const Text('Close'),
),
],
),
),
);
}
}
代码说明
-
导入必要的库
import 'package:algorand_dart/algorand_dart.dart'; import 'package:flutter/material.dart'; import 'package:ledger_algorand/ledger_algorand.dart'; import 'package:ledger_flutter/ledger.dart'; import 'package:ledger_usb/ledger_usb.dart'; import 'package:ledger_usb/usb_device.dart'; -
初始化应用
void main() { runApp(const MyApp()); } -
定义主应用状态类
class MyApp extends StatefulWidget { const MyApp({super.key}); @override State<MyApp> createState() => _MyAppState(); } -
实现应用状态
class _MyAppState extends State<MyApp> { final _ledgerUsbPlugin = LedgerUsb(); UsbDevice? device; final Algorand algorand = Algorand( algodClient: AlgodClient( apiUrl: AlgoExplorer.MAINNET_ALGOD_API_URL, ), ); @override void initState() { super.initState(); } Future<RawTransaction> _buildTransaction({required Address account}) async { final tx = await algorand.createPaymentTransaction( sender: account, receiver: account, amount: Algo.toMicroAlgos(1), ); return tx; } -
构建用户界面
@override Widget build(BuildContext context) { return MaterialApp( home: Scaffold( appBar: AppBar( title: const Text('Plugin example app'), ), body: Column( crossAxisAlignment: CrossAxisAlignment.stretch, children: [ TextButton( child: const Text('List devices'), onPressed: () async { final devices = await _ledgerUsbPlugin.listDevices(); if (devices.isEmpty) { return; } setState(() { device = devices.first; }); }, ), TextButton( onPressed: device != null ? () async { await _ledgerUsbPlugin.requestPermission(device!); } : null, child: const Text('Request permission'), ), TextButton( onPressed: device != null ? () async { await _ledgerUsbPlugin.open(device!); } : null, child: const Text('Connect'), ), TextButton( onPressed: device != null ? () async { final address = Address.fromAlgorandAddress( 'BYPEBY4EFT4M7GV4N34CMTFDQHHVEX27W5Y36UGCGS7HHA7VBDOEOQXCYM'); final tx = await _buildTransaction(account: address); final operation = AlgorandSignMsgPackOperation( accountIndex: 1, transaction: tx.toBytes(), ); final writer = ByteDataWriter(); final apdu = await operation.write(writer); final response = await _ledgerUsbPlugin.exchange( apdu, timeout: 2000, ); final reader = ByteDataReader(); reader.add(response.expand((e) => e).toList()); final signature = await operation.read(reader); final signedTx = SignedTransaction( transaction: tx, signature: signature, ); signedTx.authAddress = address; try { final txId = await algorand.sendTransaction( signedTx, waitForConfirmation: true, ); debugPrint(txId); debugPrint(signedTx.transactionId); } on AlgorandException catch (ex) { debugPrint(ex.message); } } : null, child: const Text('Exchange'), ), TextButton( onPressed: device != null ? () async { await _ledgerUsbPlugin.close(); } : null, child: const Text('Close'), ), ], ), ), ); } }
更多关于Flutter USB通信插件ledger_usb的使用的实战教程也可以访问 https://www.itying.com/category-92-b0.html
1 回复
更多关于Flutter USB通信插件ledger_usb的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html
当然，下面是一个关于如何在Flutter项目中使用ledger_usb插件进行USB通信的示例代码。这个插件通常用于与硬件设备进行USB通信，例如与加密硬件钱包交互。
环境设置
-
添加依赖： 首先，在你的
pubspec.yaml文件中添加ledger_usb依赖。dependencies: flutter: sdk: flutter ledger_usb: ^最新版本号 # 请替换为最新版本号 -
导入插件： 在你的Dart文件中导入插件。
import 'package:ledger_usb/ledger_usb.dart';
初始化与权限
在使用USB通信之前，需要确保你的应用有权限访问USB设备。在Android设备上，这通常涉及到在AndroidManifest.xml中添加相关权限，但在Flutter中，这些权限通常通过请求运行时权限来处理。
不过，ledger_usb插件已经封装好了大部分权限请求逻辑，你只需确保在AndroidManifest.xml中有以下权限：
<uses-permission android:name="android.permission.USB_PERMISSION" />
使用示例
下面是一个基本的Flutter应用示例，展示如何使用ledger_usb插件与USB设备进行通信。
import 'package:flutter/material.dart';
import 'package:ledger_usb/ledger_usb.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: Text('Ledger USB Communication Example'),
),
body: UsbCommunicationPage(),
),
);
}
}
class UsbCommunicationPage extends StatefulWidget {
@override
_UsbCommunicationPageState createState() => _UsbCommunicationPageState();
}
class _UsbCommunicationPageState extends State<UsbCommunicationPage> {
LedgerUsb? _ledgerUsb;
String _deviceStatus = 'No device connected';
@override
void initState() {
super.initState();
_initUsb();
}
void _initUsb() async {
_ledgerUsb = LedgerUsb();
// 监听设备连接
_ledgerUsb!.onDeviceConnected.listen((device) {
setState(() {
_deviceStatus = 'Device connected: ${device.productId}';
});
});
// 监听设备断开
_ledgerUsb!.onDeviceDisconnected.listen((_) {
setState(() {
_deviceStatus = 'No device connected';
});
});
// 开始扫描设备
await _ledgerUsb!.startUsbService();
}
void _sendMessageToDevice() async {
if (_ledgerUsb == null || !_ledgerUsb!.isDeviceConnected) {
print('No device connected');
return;
}
try {
// 构造一个APDU命令，这里以简单的GET VERSION命令为例
List<int> apduCommand = [0x00, 0xA4, 0x04, 0x00, 0x07, 0xA0, 0x00, 0x00, 0x00, 0x04, 0x00, 0x01, 0x00, 0x00, 0x00];
// 发送命令并接收响应
List<int> response = await _ledgerUsb!.exchangeApdu(apduCommand);
// 打印响应
print('Response: $response');
} catch (e) {
print('Error communicating with device: $e');
}
}
@override
Widget build(BuildContext context) {
return Padding(
padding: const EdgeInsets.all(16.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text(
'Device Status:',
style: TextStyle(fontSize: 18),
),
Text(
_deviceStatus,
style: TextStyle(fontSize: 16),
),
SizedBox(height: 20),
ElevatedButton(
onPressed: _sendMessageToDevice,
child: Text('Send Message to Device'),
),
],
),
);
}
@override
void dispose() {
_ledgerUsb?.stopUsbService();
super.dispose();
}
}
说明
- 初始化USB服务：在
initState方法中，初始化LedgerUsb实例并开始扫描USB设备。 - 监听设备连接和断开：通过监听
onDeviceConnected和onDeviceDisconnected事件，更新设备状态。 - 发送APDU命令：
_sendMessageToDevice方法构造一个简单的APDU命令并发送到设备，然后打印设备的响应。 - 清理资源：在
dispose方法中，停止USB服务以释放资源。
这个示例展示了基本的USB通信流程，你可以根据需要扩展和修改代码以支持更复杂的通信逻辑。
