How to validate Material RangeDatePicker from first selection(point) in Android?

Question

I want validate range-date-picker from first selection to 6 month but I couldn't.

Tried to catch(detect) first user selection(date) on range picker from this 'CalendarConstraints.Builder()'

        val constDate = CalendarConstraints.Builder()
        constDate.setValidator(object : CalendarConstraints.DateValidator {
              ...

             //this code not work correctly
              override fun isValid(date: Long): Boolean {
                   val calendar = Calendar.getInstance()
                if (initTime == 0.toLong())
                    initTime = System.currentTimeMillis()
                return if (System.currentTimeMillis() > initTime + 1000) {
                    Log.e("DateActivity", "isValid: 크다")
                    if (firstOrder == 0) {
                        firstSelect = date
                        firstOrder++
                        calendar.time = Date(firstSelect)
                        calendar.add(Calendar.MONTH, 6)
                    }
                    val remainDate = Calendar.getInstance()
                    remainDate.time = Date(date)
                    calendar > remainDate
                } else {
                    Log.e("DateActivity", "isValid: 크지 않다.")
                    true
                }
              }
        }

        builder.setCalendarConstraints(constDate.build())
        val picker = builder.build()

By time difference(System.currentTimeMillis()) try to catch first selection but when swipe picker other date catched in override fun isValid() . so I tried setOnTouchListener{} but no found way picker's setOnTouchListener in override fun isValid() cause picker built after CalendarConstraints set.

This is just static validation. I Think.

https://stackoverflow.com/a/58354878/13050313
https://stackoverflow.com/a/62080184/13050313

Answer 1

Now, I don't need this function what I asked 7 month ago, but I got this now.

//global
private const val RESET_TIME_MILLIS = 1500L
private var TERM_CALENDAR: Calendar = Calendar.getInstance()
private const val DAY_OF_TERM = 60

//prperties of Fragment or Activity
private val calendar = Calendar.getInstance()
private var firstSelect: Calendar? = null
private var secondSelect: Calendar? = null

//setValidator(below object)
object : CalendarConstraints.DateValidator {

    private val dayList = arrayListOf<Calendar>()
    private var job: Job? = null

    override fun isValid(date: Long): Boolean {
        if (job == null) {
            job = lifecycleScope.launch {
                delay(RESET_TIME_MILLIS)
                if (secondSelect != null) {
                    firstSelect = null
                    secondSelect = null
                }
                dayList.clear()
            }
        } else {
            if (job!!.isCompleted) {
                job = null
            }
        }
        calendar.time = Date(date)
        val instancCal = Calendar.getInstance().apply {
            time = Date(date)
        }
        dayList.add(instancCal)

        if (calendar.dayOfMonth() == 1 && dayList.count() == 2) {
            if (firstSelect == null) {
                firstSelect = dayList[0]
                TERM_CALENDAR.apply {
                    set(Calendar.YEAR, firstSelect!!.get(Calendar.YEAR))
                    set(Calendar.MONTH, firstSelect!!.get(Calendar.MONTH))
                    set(Calendar.DAY_OF_MONTH, firstSelect!!.get(Calendar.DAY_OF_MONTH))
                    add(
                        Calendar.DAY_OF_MONTH,
                        DAY_OF_TERM
                    )
                }
            } else if (secondSelect == null) {
                secondSelect = dayList[0]
            }
        }
        if (secondSelect != null) {
            if (calendar in firstSelect!!..TERM_CALENDAR) {
                return true
            }
            return false
        }
        return if (firstSelect == null) {
            true
        } else {
            calendar in firstSelect!!..TERM_CALENDAR
        }
    }

    override fun describeContents(): Int {
        return 0
    }

    override fun writeToParcel(dest: Parcel?, flags: Int) {
    }
}

It is like this (valid from selected to 60days)