Read QR code with external QR reader

I have an android app to read QR code. It works fine but I want to use a QR reader (No camera, reader, it is connected by USB to the device). instead of the camera of the android device.

When I press the scan button, it does this:

   public void onClick(View view) {
           IntentIntegrator integrator = new IntentIntegrator(activity);

//integrator.setDesiredBarcodeFormats(IntentIntegrator.QR_CODE_TYPES);

integrator.setDesiredBarcodeFormats(IntentIntegrator.ALL_CODE_TYPES);
        integrator.setPrompt("Scaner");
        integrator.setBeepEnabled(false);
        integrator.setBarcodeImageEnabled(false);
        integrator.initiateScan();
        }

and then I pick up the answer in onActivityResult(...)

I point to the reader and it detects the code but it does not show me anything, with the camera of the device if it works correctly.

Greetings.