UsbManager usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
Map<String, UsbDevice> usbList = usbManager.getDeviceList();

This class represents a USB device attached to the android device with the android device
 acting as the USB host.

if (!usbManager.hasPermission(usbDevice)) {
    usbPermissionReceiver = new UsbPermissionReceiver();
    //申请权限
    Intent intent = new Intent(ACTION_DEVICE_PERMISSION);
    PendingIntent mPermissionIntent = PendingIntent.getBroadcast(context, 0, intent, 0);
    IntentFilter permissionFilter = new IntentFilter(ACTION_DEVICE_PERMISSION);
    context.registerReceiver(usbPermissionReceiver, permissionFilter);
    usbManager.requestPermission(usbDevice, mPermissionIntent);
    }

 private class UsbPermissionReceiver extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent) {
      String action = intent.getAction();
      if (ACTION_DEVICE_PERMISSION.equals(action)) {
        synchronized (this) {
          UsbDevice device = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
          if (device.getDeviceName().equals(usbDevice.getDeviceName()) {
            if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
             //授权成功,在这里进行打开设备操作
            } else {
             //授权失败
            }
          }
        }
      }
    }
  }

usbInterface=usbDevice.getInterface(0);

for (int index = 0; index < usbInterface.getEndpointCount(); index++) {
        UsbEndpoint point = usbInterface.getEndpoint(index);
        if (point.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
          if (point.getDirection() == UsbConstants.USB_DIR_IN) {
            usbEndpointIn = point;
          } else if (point.getDirection() == UsbConstants.USB_DIR_OUT) {
            usbEndpointOut = point;
          }
        }
      }

This class is used for sending and receiving data and control messages to a USB device.

usbDeviceConnection = usbManager.openDevice(usbDevice);

int ret = usbDeviceConnection.bulkTransfer(usbEndpointOut, data, data.length, DEFAULT_TIMEOUT);

int inMax = inEndpoint.getMaxPacketSize(); 
ByteBuffer byteBuffer = ByteBuffer.allocate(inMax); 
UsbRequest usbRequest = new UsbRequest(); 
usbRequest.initialize(connection, inEndpoint); 
usbRequest.queue(byteBuffer, inMax); 
if(connection.requestWait() == usbRequest){ 
  byte[] retData = byteBuffer.array(); 
  for(Byte byte1 : retData){ 
    System.err.println(byte1); 
  } 
}