Show Spinner selection in text view

Question

I have changed my code with local debug not showing any errors. The problem I have is that I'm struggling to work out how to show the selected spinner text in the textview (txtMarquee) which is a scrolling text.

I do not know what code to use I am quiet new and still watching many tutorials and not having any luck.

public class MainActivity extends AppCompatActivity {
    TextView txtMarquee;
    Spinner spinnerV;

    Button btnAdmin;

    Button btnSelect;
    Button btnRefresh;
    DatabaseReference spinnerRef;
    ArrayList<String> spinnerList;
    ArrayAdapter<String> adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_main);            

        txtMarquee = (TextView) findViewById(R.id.marqueeText);

        btnSelect = findViewById(R.id.Selectbtn);
        
        txtMarquee.setSelected(true);

        btnRefresh=findViewById(R.id.btnRefresh);
        btnRefresh.setOnClickListener(view -> {
            Intent intent2 = new Intent(MainActivity.this, MainActivity.class);
            startActivity(intent2); finish();
            overridePendingTransition(0, 0);
            intent2.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
        });
    
        btnAdmin=findViewById(R.id.btnAdmin);
        btnAdmin.setOnClickListener(view -> {
            Intent intent=new Intent( MainActivity.this, Admin_login.class);
            startActivity(intent);
            overridePendingTransition(0, 0);
            intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
        });

        spinnerV = findViewById(R.id.spinner);

        spinnerRef = FirebaseDatabase.getInstance().getReference("Spinner");

        spinnerList = new ArrayList<>();
        adapter = new ArrayAdapter<>(MainActivity.this, android.R.layout.simple_spinner_dropdown_item, spinnerList);

        spinnerV.setAdapter(adapter);
        Showdata();

    }

    private void Showdata() {
        spinnerRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot) {

                for (DataSnapshot item : snapshot.getChildren()) {
                    spinnerList.add(Objects.requireNonNull(item.getValue()).toString());    
                }
                adapter.notifyDataSetChanged();
            }
            public void onCancelled(@NonNull DatabaseError databaseError) { throw databaseError.toException(); }
        });    
    }    
}