setPrintColor method Null safety

void setPrintColor(
  1. int printColor
)

设置打印颜色

Implementation

void setPrintColor(int printColor) {
  if (printColor != printColorBlack && printColor != printColorRed) {
    printColor = printColorBlack;
  }
  addString("SET COLOR ${printColor == printColorBlack ? "OFF" : "ON"}");
}