Notify data change on spinner select

Question

I can't seem to get my driver to update through my app. I have tried but with no luck. I have a possible solution but don't know what the adapter is that needs to be used. This data all happens in my MainActivity. When the new spinner item is selected. I pass the driver through to do new calculations with the correct DRIVER data.

My spinner class:

private fun Spinner( tripsheetlist: ArrayList<DataModel>): String {


        var driverlist =  tripsheetlist.distinctBy { it.DRIVER }
        var driver : String = driverlist[1].DRIVER      //this will be the default first picked driver

        spnDriver.onItemSelectedListener = object : AdapterView.OnItemSelectedListener{
            override fun onItemSelected(p0: AdapterView<*>?, p1: View?, p2: Int, p3: Long) {

                    driver  = driverlist[p2].DRIVER.toString()
                Toast.makeText(this@MainActivity, "Driver $driver selected", Toast.LENGTH_SHORT).show()

                myAdapter.notifyItemChanged(p2);
           //     myAdapter.notifyDataSetChanged()
            }
            override fun onNothingSelected(p0: AdapterView<*>?) {
            }
        }
        return driver
    }

Calling class:

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContentView(R.layout.activity_main)

        recyclerViewTripsheetlist.layoutManager = LinearLayoutManager(this)

        val spnDriver: Spinner = findViewById(R.id.spnDriver)
        var adapter = ArrayAdapter<String>(this, androidx.appcompat.R.layout.support_simple_spinner_dropdown_item)
        conn(adapter, spnDriver) 
}

    private fun conn(adapter: ArrayAdapter<String>, spnDriver: Spinner) {

        var tripsheetlist =   ArrayList<DataModel>()
       //populated by sql - removed for clarity

        populatespinner(tripsheetlist, adapter)
        var driver : String = Spinner(tripsheetlist)

        var driverList : ArrayList<DataModel> = datafilter(tripsheetlist, driver)
        tripsheetlist = driverList

        weightsum(tvTotalweight, tripsheetlist)
        totaldelNotes(tvTotaldelv,tripsheetlist)

        runOnUiThread {
            recyclerViewTripsheetlist.adapter = TableViewAdapter(tripsheetlist, driver, tvHeader, adapter)
        }
    }

Thank you for all and any help.