printData method

Future<void> printData(Printer printer, List<int> bytes, { bool longData = false, })

Implementation

Future<void> printData(
  Printer printer,
  List<int> bytes, {
  bool longData = false,
}) async {
  if (printer.connectionType == ConnectionType.USB) {
    try {
      await FlutterThermalPrinterPlatform.instance.printText(
        printer,
        Uint8List.fromList(bytes),
        path: printer.address,
      );
    } catch (e) {
      log("FlutterThermalPrinter: Unable to Print Data $e");
    }
  } else {
    try {
      final device = BluetoothDevice.fromId(printer.address!);
      if (!device.isConnected) {
        log('Device is not connected');
        return;
      }

      final services =
          (await device.discoverServices()).skipWhile((value) => value.characteristics.where((element) => element.properties.write).isEmpty);

      BluetoothCharacteristic? writeCharacteristic;
      for (var service in services) {
        for (var characteristic in service.characteristics) {
          if (characteristic.properties.write) {
            writeCharacteristic = characteristic;
            break;
          }
        }
      }

      if (writeCharacteristic == null) {
        log('No write characteristic found');
        return;
      }

      const maxChunkSize = 512;
      for (var i = 0; i < bytes.length; i += maxChunkSize) {
        final chunk = bytes.sublist(
          i,
          i + maxChunkSize > bytes.length ? bytes.length : i + maxChunkSize,
        );

        await writeCharacteristic.write(
          Uint8List.fromList(chunk),
          withoutResponse: true,
        );
      }

      return;
    } catch (e) {
      log('Failed to print data to device $e');
    }
  }
}