Java Code Examples for android.nfc.tech.IsoDep#transceive()

/**
 * Callback when a new tag is discovered by the system.
 *
 * <p>Communication with the card should take place here.
 *
 * @param tag Discovered tag
 */
@Override
public void onTagDiscovered(Tag tag) {
    Log.i(TAG, "New tag discovered");
    // Android's Host-based Card Emulation (HCE) feature implements the ISO-DEP (ISO 14443-4)
    // protocol.
    //
    // In order to communicate with a device using HCE, the discovered tag should be processed
    // using the IsoDep class.
    IsoDep isoDep = IsoDep.get(tag);
    if (isoDep != null) {
        try {
            // Connect to the remote NFC device
            isoDep.connect();
            // Build SELECT AID command for our loyalty card service.
            // This command tells the remote device which service we wish to communicate with.
            Log.i(TAG, "Requesting remote AID: " + SAMPLE_LOYALTY_CARD_AID);
            byte[] command = BuildSelectApdu(SAMPLE_LOYALTY_CARD_AID);
            // Send command to remote device
            Log.i(TAG, "Sending: " + ByteArrayToHexString(command));
            byte[] result = isoDep.transceive(command);
            // If AID is successfully selected, 0x9000 is returned as the status word (last 2
            // bytes of the result) by convention. Everything before the status word is
            // optional payload, which is used here to hold the account number.
            int resultLength = result.length;
            byte[] statusWord = {result[resultLength-2], result[resultLength-1]};
            byte[] payload = Arrays.copyOf(result, resultLength-2);
            if (Arrays.equals(SELECT_OK_SW, statusWord)) {
                // The remote NFC device will immediately respond with its stored account number
                String accountNumber = new String(payload, "UTF-8");
                Log.i(TAG, "Received: " + accountNumber);
                // Inform CardReaderFragment of received account number
                mAccountCallback.get().onAccountReceived(accountNumber);
            }
        } catch (IOException e) {
            Log.e(TAG, "Error communicating with card: " + e.toString());
        }
    }
}
 

static byte[] transceiveApdu(IsoDep tag, byte[] cmd) {
	if (tag != null) {
		try {
			if (!tag.isConnected()) {
				tag.connect();
				tag.setTimeout(10000);
			}

			return tag.transceive(cmd);
		} catch (Exception e) {
		}
	}
	return null;
}