How to Create Dialog Series Timepicker - Kotlin

MyDialogFragment.kt

class MyDialogFragment : DialogFragment() {

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {

        val dialog = activity?.let {
            // デフォルトの時刻を用意
            val c = Calendar.getInstance()
            val hour = c[Calendar.HOUR_OF_DAY]
            val minute = c[Calendar.MINUTE]

            TimePickerDialog(it, null, hour, minute, true)
        }
        return dialog ?: throw IllegalStateException("アクティビティがNullです。")
    }
}