语境；arrayadapter stateadapter=新的arrayadapter（mainactivity.this，andriod.r.layout.spinner，state）；

StateAdapter.setDropDownViewResource(andriod.R.layout.spinner_dropdown_item);
    spinner.setAdapter(StateAdapter);
    spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

        public void OnItemSelected(AdopterView<?> parent, View view, int position, long id) {
            String yourState = spinner.getSelectedItem().toString();
            if (!yourState.equals("- Choose your state -")) {
                spinner.setText("You chose" + yourState);
            } else {
                txtState.setText("Choose a state");

            }
        }
        public void onNothingSeleced(AdopterView<?> parent) {
        }

    });