Several questions about DatePickerDialog using DialogFragment

I need to set a datePickerDialog, and disable all future dates and all dates before one month ago, for example: If today is 04/05/2020 I need the range from 04/04/2020 - 04/05/2020.

How can I set it? I tried the min/max approach but the problem is that I uses different fragment that extended DialogFragment.

This is my code:

class DatePickerFragmentDialog : DialogFragment(), DatePickerDialog.OnDateSetListener {

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        // Use the current date as the default date in the picker
        val c =  Calendar.getInstance()
        val year = c.get(Calendar.YEAR)
        val month = c.get(Calendar.MONTH)
        val day = c.get(Calendar.DAY_OF_MONTH)
        // Create a new instance of DatePickerDialog and return it
        return DatePickerDialog(requireActivity(), this, year, month, day)
    }
   override fun onDateSet(view: DatePicker?, year: Int, month: Int, dayOfMonth: Int) {

    }
 }

And I call it from my main fragment here:

DatePickerFragmentDialog().show(parentFragmentManager, "datePicker" )

Also - since getSupportFragment was deprecated I call here parentFragmentManager, this is the right choice?

And final question - I can get the user pick from onDateSet function, but the problem is that this function is in DatePickerFragmentDialog how can I pass the variables from this function to my main fragment and views?

For your first question, you can set min date and max date inside onCreateDialog:

override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
    val c =  Calendar.getInstance()
    val year = c.get(Calendar.YEAR)
    val month = c.get(Calendar.MONTH)

    val day = c.get(Calendar.DAY_OF_MONTH)
    val d = DatePickerDialog(requireActivity(), this , year, month, day)
    val dp = d.datePicker

    dp.maxDate = //Do your calculation
    dp.min= //Do your calculation

    return d
}

And for your other question - you can implement the DatePickerDialog.OnDateSetListener inside your main fragment and call onDateSet from there