getPrinterMode method Null safety

Future<PrinterMode> getPrinterMode(
  1. PrinterDevice device
)

获取打印机的模式（当前的打印指令集） device 打印机设备

Implementation

Future<PrinterMode> getPrinterMode(PrinterDevice device) async {
  var status = await getPrinterStatus(device, PrinterMode.esc);
  if (status != null) {
    return PrinterMode.esc;
  }
  status = await getPrinterStatus(device, PrinterMode.cpcl);
  if (status != null) {
    return PrinterMode.cpcl;
  }
  status = await getPrinterStatus(device, PrinterMode.tspl);
  if (status != null) {
    return PrinterMode.tspl;
  }
  return PrinterMode.zpl;
}