Android USB 通信开发

news2025/6/8 9:06:32

Android USB 通信开发主要涉及两种模式：主机模式(Host Mode)和配件模式(Accessory Mode)。以下是开发USB通信应用的关键知识点和步骤。

1. 基本概念

主机模式(Host Mode)

Android设备作为USB主机，控制连接的USB设备
需要设备支持USB主机功能(通常需要OTG支持)

配件模式(Accessory Mode)

Android设备作为USB配件被其他主机控制
需要设备支持USB配件模式

2. 开发准备

清单文件配置

<!-- 声明USB主机功能 -->
<uses-feature android:name="android.hardware.usb.host" />

<!-- 声明USB配件功能（如果需要） -->
<uses-feature android:name="android.hardware.usb.accessory" />

<!-- 添加必要的权限 -->
<uses-permission android:name="android.permission.USB_PERMISSION" />

3. USB主机模式开发

发现连接的USB设备

UsbManager usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
HashMap<String, UsbDevice> deviceList = usbManager.getDeviceList();

请求设备权限

private static final String ACTION_USB_PERMISSION = "com.example.USB_PERMISSION";

PendingIntent permissionIntent = PendingIntent.getBroadcast(this, 0, 
    new Intent(ACTION_USB_PERMISSION), PendingIntent.FLAG_IMMUTABLE);

IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
registerReceiver(usbReceiver, filter);

usbManager.requestPermission(device, permissionIntent);

广播接收器处理权限结果

private final BroadcastReceiver usbReceiver = new BroadcastReceiver() {
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (ACTION_USB_PERMISSION.equals(action)) {
            synchronized (this) {
                UsbDevice device = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
                if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
                    if(device != null){
                        // 权限已授予，可以通信
                        openDevice(device);
                    }
                } else {
                    Log.d(TAG, "权限被拒绝 for device " + device);
                }
            }
        }
    }
};

打开设备并通信

private void openDevice(UsbDevice device) {
    UsbInterface intf = device.getInterface(0);
    UsbEndpoint endpoint = intf.getEndpoint(0);
    
    UsbDeviceConnection connection = usbManager.openDevice(device);
    if (connection == null) return;
    
    connection.claimInterface(intf, true);
    
    // 发送数据
    byte[] sendData = "Hello".getBytes();
    int sent = connection.bulkTransfer(endpoint, sendData, sendData.length, 0);
    
    // 接收数据
    byte[] receiveData = new byte[64];
    int received = connection.bulkTransfer(endpoint, receiveData, receiveData.length, 0);
}

4. USB配件模式开发

清单文件配置

<activity ...>
    <intent-filter>
        <action android:name="android.hardware.usb.action.USB_ACCESSORY_ATTACHED" />
    </intent-filter>
    <meta-data 
        android:name="android.hardware.usb.action.USB_ACCESSORY_ATTACHED"
        android:resource="@xml/accessory_filter" />
</activity>

配件过滤器(xml/accessory_filter.xml)

<resources>
    <usb-accessory 
        manufacturer="YourCompany" 
        model="YourModel" 
        version="1.0" />
</resources>

检测配件连接

UsbManager usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
UsbAccessory[] accessoryList = usbManager.getAccessoryList();

if (accessoryList != null && accessoryList.length > 0) {
    UsbAccessory accessory = accessoryList[0];
    openAccessory(accessory);
}

打开配件通信

private void openAccessory(UsbAccessory accessory) {
    ParcelFileDescriptor fd = usbManager.openAccessory(accessory);
    if (fd != null) {
        FileDescriptor fileDescriptor = fd.getFileDescriptor();
        FileInputStream inputStream = new FileInputStream(fileDescriptor);
        FileOutputStream outputStream = new FileOutputStream(fileDescriptor);
        
        // 现在可以通过输入输出流进行通信
    }
}