searchview is not working with custome adapter kotlin

Question

Here is my code for serachview and custom adapter. The function inside the custom adapter is not being called. No error but it is not working , nothin happen when i try to search in my list :

searchView.setOnQueryTextListener(object : SearchView.OnQueryTextListener {

            override fun onQueryTextChange(newText: String): Boolean {
                if (TextUtils.isEmpty(newText)) {
                    // adapter?.filter
                    adapter?.filter("")
                    listView.clearTextFilter();
                } else {
                    Log.i("searched ", newText)
                    adapter?.filter(newText);
                }
                return true;
            }

            override fun onQueryTextSubmit(query: String): Boolean {
                // task HERE
                return false
            }

        })

My custom adapter inner class inside a fragment :

   inner class CustomAdapter(
        private val context: Context,
        private val ItemDataList: List<ContactEntity>
    ) : BaseAdapter() {

        private val inflater: LayoutInflater =
            this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater

        override fun getCount(): Int {
            return ItemDataList.size
        }

        override fun getItem(position: Int): Int {
            return position
        }

        override fun getItemId(position: Int): Long {
            return position.toLong()
        }


        override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
            var contact = ItemDataList[position]

            
            val rowView = inflater.inflate(R.layout.list_item_contact, parent, false)
            rowView.findViewById<TextView>(R.id.customer_name).text = contact.name
            rowView.tag = position
            return rowView
        }


        // Filter Class
        fun filterCustomer(charText: String) {
            Log.i("searched inside:", charText)
            var charText = charText
            charText = charText.toLowerCase(Locale.getDefault())
            mContacts = null
            if (charText.isEmpty()) {
               mContacts = ItemDataList
            } else {
                for (contact in ItemDataList) {
                    if (contact.name?.toLowerCase(Locale.getDefault())?.contains(charText)!!) {
                        mContacts = listOf(contact)
                    }
                }
            }
            notifyDataSetChanged()
        }

       

        
    }

Here is my xml,I added searchview just above the listview :

 <SearchView
            android:id="@+id/searchView1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>
        <ListView
            android:id="@+id/contact_list"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            />

Answer 1

My code was not working beacuse, I was not properly accessing the method of Custom adapter. The instance of adapter was null.

I changed this:

 adapter?.filter(newText);

to that:

 (listView.adapter as CustomAdapter?)?.filter(newText)

And it worked!