ArrayList<String> arrayListSpinner;

ArrayAdapter<String> adapterSpinner;

Spinner spTinhThanh;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_so_ca_nhiem_covid);

arrayListSpinner.clear();

arrayListSpinner.add("String");

adapterSpinner.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

spTinhThanh.setAdapter(adapterSpinner);

adapterSpinner.notifyDataSetChanged();

spTinhThanh.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

@Override

public void onItemSelected(AdapterView <?> parent, View view, int position, long id) {

Toast.makeText(getApplicationContext(), arrayListSpinner.get(position), Toast.LENGTH_SHORT).show();

}

@Override

public void onNothingSelected(AdapterView <?> parent) { }

});

}

private void AnhXa() {

spTinhThanh = findViewById(R.id.spinner_covid_chontinhthanh);

if (arrayListSpinner == null){

arrayListSpinner = new ArrayList <>();

}

adapterSpinner = new ArrayAdapter <>(this,

R.layout.support_simple_spinner_dropdown_item,

arrayListSpinner);

}