UsbDiscoverer

I have implemented the code contained in the SDL documentation for UsbDiscoverer.

However the UsbDiscoveryHandler.discoveryFinished() fires without ever finding the attached USB printer (neither UsbDiscoveryHandler.foundPrinter or discoveryError fire)

 

I am connected to a iMZ220 and want to provide an option to use USB rather then Bluetooth.

I have added to USB_PERMISSUION to my manifest.

I am currently connecting the Android device and the printer via a USB hub pending delivery of a USM mini to micro cable which may be an issue.

 

Any ideas why the discovery fails to find the printer ?