写一个android USB程序与USB设备进行USB通信的demo，将接收到的数据发送回去。

很抱歉，作为AI语言模型，我没有办法提供完整的代码示例，但我可以提供一些参考。

首先，你需要在AndroidManifest.xml文件中添加以下权限：

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

然后在你的Activity中实现USB设备的连接和通信，可以参考以下代码：

public class MainActivity extends AppCompatActivity {

    private static final String TAG = MainActivity.class.getSimpleName();

    private UsbManager mUsbManager;
    private PendingIntent mPermissionIntent;
    private UsbDevice mDevice;
    private UsbInterface mInterface;
    private UsbEndpoint mEndpointIn;
    private UsbEndpoint mEndpointOut;
    private UsbDeviceConnection mConnection;

    private static final int TIMEOUT = 5000;
    private static final int VID = 0x1234; // USB设备的VID
    private static final int PID = 0x5678; // USB设备的PID

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mUsbManager = (UsbManager) getSystemService(Context.USB_SERVICE);

        mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent("ACTION_USB_PERMISSION"), 0);
        IntentFilter filter = new IntentFilter("ACTION_USB_PERMISSION");
        registerReceiver(mUsbReceiver, filter);

        // 查找USB设备
        for (UsbDevice device : mUsbManager.getDeviceList().values()) {
            if (device.getVendorId() == VID && device.getProductId() == PID) {
                mDevice = device;
                break;
            }
        }

        if (mDevice != null) {
            // 请求USB设备的权限
            mUsbManager.requestPermission(mDevice, mPermissionIntent);
        } else {
            Log.e(TAG, "USB Device not found!");
        }
    }

    private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if ("ACTION_USB_PERMISSION".equals(action)) {
                synchronized (this) {
                    UsbDevice device = (UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
                    if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
                        if (device != null) {
                            mConnection = mUsbManager.openDevice(device);
                            if (mConnection != null) {
                                // 查找USB设备的接口和端点
                                for (int i = 0; i < device.getInterfaceCount(); i++) {
                                    UsbInterface usbInterface = device.getInterface(i);
                                    if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_CDC_DATA) {
                                        mInterface = usbInterface;
                                        break;
                                    }
                                }
                                if (mInterface != null) {
                                    for (int i = 0; i < mInterface.getEndpointCount(); i++) {
                                        UsbEndpoint endpoint = mInterface.getEndpoint(i);
                                        if (endpoint.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
                                            if (endpoint.getDirection() == UsbConstants.USB_DIR_IN) {
                                                mEndpointIn = endpoint;
                                            } else if (endpoint.getDirection() == UsbConstants.USB_DIR_OUT) {
                                                mEndpointOut = endpoint;
                                            }
                                        }
                                    }
                                    if (mEndpointIn != null && mEndpointOut != null) {
                                        // USB设备连接成功，开始进行数据通信
                                        new Thread(new Runnable() {
                                            @Override
                                            public void run() {
                                                byte[] buffer = new byte[1024];
                                                int length;

                                                // 发送数据到USB设备
                                                byte[] data = "Hello USB Device!".getBytes();
                                                int sent = mConnection.bulkTransfer(mEndpointOut, data, data.length, TIMEOUT);
                                                Log.d(TAG, "Sent: " + sent);

                                                // 接收USB设备发送的数据
                                                while (true) {
                                                    length = mConnection.bulkTransfer(mEndpointIn, buffer, buffer.length, TIMEOUT);
                                                    if (length > 0) {
                                                        String message = new String(buffer, 0, length);
                                                        Log.d(TAG, "Received: " + message);

                                                        // 发送接收到的数据回去
                                                        sent = mConnection.bulkTransfer(mEndpointOut, buffer, length, TIMEOUT);
                                                        Log.d(TAG, "Sent: " + sent);
                                                    }
                                                }
                                            }
                                        }).start();
                                    }
                                }
                            }
                        }
                    } else {
                        Log.e(TAG, "Permission denied!");
                    }
                }
            }
        }
    };

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(mUsbReceiver);
        if (mConnection != null) {
            mConnection.close();
        }
    }
}

在上面的代码中，我们先查找USB设备，然后请求USB设备的权限。如果用户允许了访问权限，我们就打开USB设备，并查找USB设备的接口和端点。最后，我们在一个新线程中进行数据通信，发送数据到USB设备，并不断接收USB设备发送的数据，并将接收到的数据发送回去。

希望这些代码能够帮助你开始编写你的USB通信程序！