introductoryRoundUnitText method
将 introductoryRoundUnit 转换为中文描述
"day"->"天""week"->"周""month"->"月""year"->"年"- 其他/null ->
""
Implementation
String introductoryRoundUnitText() {
switch (introductoryRoundUnit) {
case "day":
return "天";
case "week":
return "周";
case "month":
return "月";
case "year":
return "年";
default:
return "";
}
}