Android Spinner Widget

    spinner = findViewById(R.id.spinner);
    String[] strArrSpinner = { "A", "B", "C" };
    ArrayAdapter spinnerAdapter = new ArrayAdapter(
        this,
        android.R.layout.simple_spinner_item,
        strArrSpinner
    );
    spinnerAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(spinnerAdapter);

    Button btnShowSpinnerSelected = findViewById(R.id.btnShowSpinnerSelected);
    btnShowSpinnerSelected.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Toast.makeText(getApplicationContext(),
            spinner.getSelectedItem().toString(),
            Toast.LENGTH_LONG).show();
        }
    });