The time used for the delay in the example code does appear arbitrary. But the essence is to ensure all the data are sent out and then received by the printer, before we close the connection. This is because that the Android OS doesn't tell the application whether the data has been sent and received completely.

A better way is to check the status of the printer (i.e. getCurrentStatus()) to make sure the following conditions are met before closing the connection.

boolean isConnectionClosed = false;
while (!isConnectionClosed) {
    PrinterStatus status = printer.getCurrentStatus();
    if (!status.isReceiveBufferFull && !status.isPartialFormatInProgress) {
        isConnectionClosed = true;
        printer.getConnection().close();
    } else {
        Thread.sleep(100); // Pause for 100ms
    }
}

Hi @SSi1, we tried the solution, when the Bluetooth Data Transfer is in progress, printer.getCurrentStatus() is throwing Malformed status exception. So we are trying something like this and it seems to work. Please confirm checking for status multiple times during Bluetooth Data transfer does not impede the actual data transfer.

boolean fileTransferComplete = false;
int counter = 0;
try {
    while (!fileTransferComplete) {

        try {
            status = zebraPrinter.getCurrentStatus();
        } catch (ConnectionException e) {
            counter += 1;
            Thread.sleep(100); // Pause for 100ms..
            if (counter > MAXIMUM_WAIT_COUNTER) {
                return false;
            }
            continue;
        }

        if (!status.isReceiveBufferFull && !status.isPartialFormatInProgress) {
            fileTransferComplete = true;
        } else {
            counter += 1;

            if (counter > MAXIMUM_WAIT_COUNTER) {
                return false;
            }
            Thread.sleep(100); // Pause for 100ms
        }

Also it would be nice to have the samples updated with this.