Material DateRangePicker enable Accept button with single date

Question

I have a material daterangepicker to select a single date or a range. If i want to select a single date i must select the same date twice to enable "Accept" button. There are something to enable Accept button when select the first date?

I see in MaterialDatePicker.java that they use:

pickerFragment.addOnSelectionChangedListener(
    new OnSelectionChangedListener<S>() {
      @Override
      public void onSelectionChanged(S selection) {
        updateHeader();
        confirmButton.setEnabled(dateSelector.isSelectionComplete());
      }

      @Override
      public void onIncompleteSelectionChanged() {
        confirmButton.setEnabled(false);
      }
    });

I think i need to use this or something similar but i cant access to this method.

I use this to show DateRangePicker:

private fun showDatePicker() {
    val builder = MaterialDatePicker.Builder.dateRangePicker()
    builder.setTheme(R.style.CustomCalendarDatePickerTheme)
    builder.setCalendarConstraints(limitRange().build())

    val picker = builder.build()
    picker.addOnPositiveButtonClickListener {
        tv_date.text = formatRange(it.first!!, it.second!!)
        startDate = it.first
        endDate = it.second
    }

    picker.show(supportFragmentManager, picker.toString())
}

Answer 1

Finally I create a class that extend RangeDateSelector and overriding select() function, when is the first time I set the date in both start and end:

@SuppressLint("RestrictedApi")
class CustomMaterialDatePicker : RangeDateSelector() {

    private var first = true
    private var firstDate: Long? = null

    override fun select(selection: Long) {
        if (first || selection < firstDate!!) {
            super.select(selection)
            super.select(selection)
            firstDate = selection
            first = false
        } else {
            super.select(firstDate!!)
            super.select(selection)
            if (selection != firstDate) {
                first = true
            }
        }
    }
}

And I create DateRangePicker like this:

@SuppressLint("RestrictedApi")
private fun showDatePicker() {
    val selector = CustomMaterialDatePicker()
    val builder = MaterialDatePicker.Builder.customDatePicker(selector)
    builder.setTheme(R.style.CustomCalendarDatePickerTheme)
    builder.setCalendarConstraints(limitRange().build())

    val picker = builder.build()
    picker.addOnPositiveButtonClickListener {
        tv_date.text = formatRange(it.first!!, it.second!!)
        startDate = it.first
        endDate = it.second
    }

    picker.show(supportFragmentManager, picker.toString())
}