Kotlin, Calendar, Date

private fun getFirstWeek(year:Int, month:Int):Int{

    var strMonth = "0"    if(month < 10) strMonth += month
    else strMonth = month.toString()

    var strDate = year.toString() + strMonth +"01"    val format = SimpleDateFormat("yyyyMMdd")
    val date = format.parse(strDate)
    val calendar = Calendar.getInstance()
    calendar.time = date

    return calendar.get(Calendar.DAY_OF_WEEK)
}

private fun getWeekStr(week:Int):String{
    when(week){
        1 -> return "日"        2 -> return "月"        3 -> return "火"        4 -> return "水"        5 -> return "木"        6 -> return "金"        7 -> return "土"    }
    return ""}