CODEWITHSUNDEEP
androidbarcode-scannerkeyevent
Tuby
Tuby

Reputation: 3253

How to distinguish between android KeyEvent and external device KeyEvent

I'm reading barcodes/cards with external device connected to android device by USB.

External device sends it's input as KeyEvent to Activity and I can read it in dispatchKeyEvent() method inside Activity like this

@Override public boolean dispatchKeyEvent(KeyEvent event) {
    if (event.getAction() == KeyEvent.ACTION_DOWN) {
        externalDeviceService.onNewInputFromExternalDevice(((char) event.getUnicodeChar()));
    }
    return super.dispatchKeyEvent(event);
}

But for example when there is focus on some EditText, it types external device input to that input field instead of just delegating to service.

Is there a way to distinguish between input from android device(soft keyboard) and from external device(RFID card reader or barcode scanner)?

Obvious solution would be keyEvent.getDevice().getName(), and recognize external device to handle event appropriately, but that binds me to specific devices which is huge limitation. Maybe there is a way to check if KeyEvent comes from android soft keyboard?

Any insight on this would be appreciated.

Upvotes: 0

Views: 1481

Answers (1)

Tuby
Tuby

Reputation: 3253

For anyone interested in the future, I send KeyEvents from dispatchKeyEvent() to some outside service, if next character appears in specified amount of time after previous, it means that it comes from scanner/rfid. In other cases I send KeyEvent back to Activity and call super.dispatchKeyEvent()

@Edit Another way is getting list of USB Connected devices from UsbManager. Use that list to determine if KeyEvent parent is inside that list to distinguish. Caveat is that, if you connect hardware keyboard, it treats KeyEvents as it comes from Barcode/RFID card Scanner

Upvotes: 1

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