Kotlin] MultiSelectListPreference 선택값 summary에 반영

val Pref = findPreference("Category") as MultiSelectListPreference
Pref.summary = Pref.values.joinToString(", ")

//sumary에 반영 
Pref.setOnPreferenceChangeListener { preference, newValue ->
 	 val newValueSet = newValue as? HashSet<*>
         ?: return@setOnPreferenceChangeListener true

     Pref.summary = newValueSet.joinToString(", ")  
     true
}