external usb camera android studio

Good I am trying to launch an intent to visualize an external camera through usb, the thing is that I do not hit the key, since everything related that I have found is on the mobile's own camera .. my question is if there is any way of throwing the external camera through the usb port, thanks

Hello again I have managed to open the two cameras of the mobile and save the photos, on the external USB camera I have managed to recognize the usb but I do not know how to say it is a camera and that is what you use.

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

    //mInfo = (ImageView) findViewById(R.id.imageview);
    cameraButton = (Button) findViewById(R.id.button_image);
    gallery = (Button) findViewById(R.id.button_gallery);
    imageView = (ImageView) findViewById(R.id.imageview);

    mLogger = new Logger(this);
    mLogger.setMode(Logger.MODE_TOAST);

    mUsbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
    usbConnection();
    mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);
    IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
    registerReceiver(mUsbReceiver, filter);

    mUsbManager.requestPermission(device, mPermissionIntent);

    UsbInterface intf = device.getInterface(0);
    UsbEndpoint endpoint = intf.getEndpoint(0);
    UsbDeviceConnection connection = mUsbManager.openDevice(device);
    connection.claimInterface(intf, forceClaim);
    //creo que falla aquí abajo,en bytes, como podría hacerlo en otro hilo?
    connection.bulkTransfer(endpoint,bytes, bytes.length, TIMEOUT);//do in another thread

    mLogger.log("usb", "//////////////////////////////////////: " + mCameraId);

    // Servicio USB --> Definirlo como Cámara (Añadir Cámara)
    //CameraManager manager = (CameraManager) mUsbManager;


    CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
    try {
    String[] cameraList = manager.getCameraIdList();
    } catch (CameraAccessException e) {
    e.printStackTrace();
    }


    if (manager != null) {
    try {
    for (String mCameraId : manager.getCameraIdList()) {
    CameraCharacteristics cameraCharacteristics = manager.getCameraCharacteristics(mCameraId);
    mLogger.log("usb", "//////////////////////////////////////: " + mCameraId);

    manager.openCamera(mCameraId, mStateCallback, null);
    }

    } catch (CameraAccessException e) {
    e.printStackTrace();
    }
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
    cameraButton.setEnabled(false);
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
    }
  }
}