Ваш метод setSpinner ():
private void setSpinner(final Context context, Spinner spinnerCity, List<Object> spinnerItem) {
final ArrayAdapter adapter = new ArrayAdapter(context, android.R.layout.simple_spinner_item, spinnerItem);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerCity.setAdapter(adapter);
spinnerCity.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
String citySelected = parent.getItemAtPosition(position).toString();
//adapter.notifyDataSetChanged();
Toast.makeText(context, "City : " + citySelected, Toast.LENGTH_LONG).show();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
Toast.makeText(context, "Not Selected", Toast.LENGTH_LONG).show();
}
});
}
CityActivity.java:
Spinner spinnerCity = findViewById(R.id.spinner);
String[] spinnerItem = {"A", "B", "C", "D", "E"};
setSpinner(CityActivity.this, spinnerCity, Arrays.<Object>asList(spinnerItem));