Here is the edited code for the SearchView and working fine:
val searchText = query!!.toLowerCase(Locale.getDefault())
if (searchText.isNotEmpty()){
dbList.forEach {
val txtKrString = Normalizer.normalize(it.txtKr, Normalizer.Form.NFD)
.replace("[^\\p{ASCII}]".toRegex(), "")
val txtFrString = Normalizer.normalize(it.txtFr, Normalizer.Form.NFD)
.replace("[^\\p{ASCII}]".toRegex(), "")
if (txtKrString.toLowerCase(Locale.getDefault()).contains(searchText)){
tempdbList.add(it)
}else if (txtFrString.toLowerCase(Locale.getDefault()).contains(searchText)){
tempdbList.add(it)
}
}
this@Main.recyclerv.adapter!!.notifyDataSetChanged()
}