Flutter USB标准通信插件psdk_usb_standard的使用

psdk_usb_standard 是一个用于在 Flutter 应用中实现与 USB 设备进行标准通信的插件。它允许你通过 USB 接口与设备进行数据传输，适用于各种需要与 USB 设备交互的场景。

以下是使用 psdk_usb_standard 插件的基本步骤：

1. 添加依赖

首先，你需要在 pubspec.yaml 文件中添加 psdk_usb_standard 插件的依赖：

dependencies:
  flutter:
    sdk: flutter
  psdk_usb_standard: ^1.0.0  # 请使用最新的版本

然后运行 flutter pub get 来获取依赖。

2. 配置 Android 项目

在 Android 项目中，你需要在 AndroidManifest.xml 文件中添加以下权限：

<uses-permission android:name="android.permission.USB_PERMISSION" />
<uses-feature android:name="android.hardware.usb.host" />

3. 初始化插件

在 Flutter 应用中初始化 psdk_usb_standard 插件：

import 'package:psdk_usb_standard/psdk_usb_standard.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await PsdkUsbStandard.initialize();
  runApp(MyApp());
}

4. 发现并连接 USB 设备

你可以使用 PsdkUsbStandard 来发现并连接 USB 设备：

import 'package:psdk_usb_standard/psdk_usb_standard.dart';

Future<void> connectToUsbDevice() async {
  List<UsbDevice> devices = await PsdkUsbStandard.getDevices();
  if (devices.isNotEmpty) {
    UsbDevice device = devices.first;
    await PsdkUsbStandard.connect(device);
    print('Connected to device: ${device.deviceName}');
  } else {
    print('No USB devices found');
  }
}

5. 发送和接收数据

连接成功后，你可以通过 PsdkUsbStandard 发送和接收数据：

Future<void> sendData() async {
  List<int> data = [0x01, 0x02, 0x03]; // 要发送的数据
  await PsdkUsbStandard.sendData(data);
  print('Data sent');
}

Future<void> receiveData() async {
  List<int> data = await PsdkUsbStandard.receiveData();
  print('Data received: $data');
}

6. 断开连接

使用完毕后，记得断开与 USB 设备的连接：

Future<void> disconnect() async {
  await PsdkUsbStandard.disconnect();
  print('Disconnected from USB device');
}

7. 处理异常

在实际使用中，你可能会遇到各种异常情况（如设备未连接、权限被拒绝等），因此建议在代码中添加异常处理：

Future<void> connectToUsbDevice() async {
  try {
    List<UsbDevice> devices = await PsdkUsbStandard.getDevices();
    if (devices.isNotEmpty) {
      UsbDevice device = devices.first;
      await PsdkUsbStandard.connect(device);
      print('Connected to device: ${device.deviceName}');
    } else {
      print('No USB devices found');
    }
  } catch (e) {
    print('Failed to connect to USB device: $e');
  }
}

8. 完整示例

以下是一个完整的示例，展示了如何使用 psdk_usb_standard 插件与 USB 设备进行通信：

import 'package:flutter/material.dart';
import 'package:psdk_usb_standard/psdk_usb_standard.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await PsdkUsbStandard.initialize();
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: UsbCommunicationPage(),
    );
  }
}

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

class _UsbCommunicationPageState extends State<UsbCommunicationPage> {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('USB Communication'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            ElevatedButton(
              onPressed: connectToUsbDevice,
              child: Text('Connect to USB Device'),
            ),
            ElevatedButton(
              onPressed: sendData,
              child: Text('Send Data'),
            ),
            ElevatedButton(
              onPressed: receiveData,
              child: Text('Receive Data'),
            ),
            ElevatedButton(
              onPressed: disconnect,
              child: Text('Disconnect'),
            ),
          ],
        ),
      ),
    );
  }

  Future<void> connectToUsbDevice() async {
    try {
      List<UsbDevice> devices = await PsdkUsbStandard.getDevices();
      if (devices.isNotEmpty) {
        UsbDevice device = devices.first;
        await PsdkUsbStandard.connect(device);
        print('Connected to device: ${device.deviceName}');
      } else {
        print('No USB devices found');
      }
    } catch (e) {
      print('Failed to connect to USB device: $e');
    }
  }

  Future<void> sendData() async {
    try {
      List<int> data = [0x01, 0x02, 0x03]; // 要发送的数据
      await PsdkUsbStandard.sendData(data);
      print('Data sent');
    } catch (e) {
      print('Failed to send data: $e');
    }
  }

  Future<void> receiveData() async {
    try {
      List<int> data = await PsdkUsbStandard.receiveData();
      print('Data received: $data');
    } catch (e) {
      print('Failed to receive data: $e');
    }
  }

  Future<void> disconnect() async {
    try {
      await PsdkUsbStandard.disconnect();
      print('Disconnected from USB device');
    } catch (e) {
      print('Failed to disconnect: $e');
    }
  }
}