попълване на spinner от низов масив

Аз съм доста нов в това и имам въпрос, който вероятно е доста прост.

Имам 3 спинера и искам да попълня всеки спинер от масив въз основа на избора, направен от потребителя на предишните спинери.

Точно сега съм го настроил да показва тост с избраните данни, но искам да настроя дейност за отваряне, но това е по-късно. Точно сега трябва да знам как да попълня въртящия се бутон от масив от strings.xml.

.Java

import java.util.ArrayList;
import java.util.List;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;

/**
 * @author madonk
 *
 */
public class Region extends Activity {

Spinner sp1,sp2,sp3;
ArrayAdapter<String> reg_adp,sw_city_adp,sw_lake_charles_adp;
List<String> regions,sw_cities,sw_lake_charles;
int pos;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_region);

    regions=new ArrayList<String>();

    regions.add("Select a Region");
    regions.add("Southwest");

    sp1= (Spinner) findViewById(R.id.regions_spinner);
    sp2= (Spinner) findViewById(R.id.sw_city_spinner);
    sp3= (Spinner) findViewById(R.id.sw_lake_charles_spinner);

    reg_adp=new ArrayAdapter<String> (this,android.R.layout.simple_dropdown_item_1line,regions);
    reg_adp.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
    sp1.setAdapter(reg_adp);

    sp1.setOnItemSelectedListener(new OnItemSelectedListener() {

        public void onItemSelected(AdapterView<?> arg0, View arg1,
                int arg2, long arg3) {
            // TODO Auto-generated method stub
            pos=arg2;
            add();

        }

        private void add() {
            // TODO Auto-generated method stub
            Toast.makeText(getBaseContext(), ""+pos, Toast.LENGTH_SHORT).show();

            switch(pos)
            {
            case 0:
                sw_cities= new ArrayList<String>();                    
                sw_cities.add("Select a City");


                sw_city_adp=new ArrayAdapter<String>(Region.this,
                        android.R.layout.simple_dropdown_item_1line,sw_cities);
                sw_city_adp.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
                sp2.setAdapter(sw_city_adp);

                select();

                break;
            case 1:
                sw_cities= new ArrayList<String>(); 
                sw_cities.add("Select a City");
                sw_cities.add("Lake Charles");
                sw_cities.add("Iowa");
                sw_cities.add("Lake Arthur");

                sw_city_adp=new ArrayAdapter<String>(Region.this,
                        android.R.layout.simple_dropdown_item_1line,sw_cities);
                sw_city_adp.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
                sp2.setAdapter(sw_city_adp);

                select();

                break;
            }

        }

        private void select() {
            // TODO Auto-generated method stub

            sp2.setOnItemSelectedListener(new OnItemSelectedListener() {

                public void onItemSelectedregions(AdapterView<?> arg0, View arg1,
                        int arg2, long arg3) {
                    // TODO Auto-generated method stub

                }

                public void onNothingSelected(AdapterView<?> arg0) {
                    // TODO Auto-generated method stub

                }

                public void onItemSelected(AdapterView<?> arg0, View arg1,
                        int arg2, long arg3) {
                    // TODO Auto-generated method stub

                }

                public void onNothingSelectedregions(AdapterView<?> arg0) {
                    // TODO Auto-generated method stub

                }
            });

        }

        public void onNothingSelectedcities(AdapterView<?> arg0) {
            // TODO Auto-generated method stub

        }

        public void onNothingSelected(AdapterView<?> arg0) {
            // TODO Auto-generated method stub

        }
    });
    }

stings.xml

<resources>

    <string name="app_name">Louisiana Festivals</string>
    <string name="menu_settings">Settings</string>
    <string name="title_activity_region">Select a Region</string>
    <string-array name="regions_array">
        <item >Southwest</item>
    </string-array>
        <string name="select_a_region">Select a Region</string>
    <string-array name="southwest_cities">
        <item >Lake Charles</item>
        <item >Iowa</item>
    </string-array>
    <string name="sw_select_a_city">Select a City</string>
    <string-array name="lake_charles">
        <item>Contraband days Pirate Festival</item>
        <item>Other festival to be determined</item>
    </string-array>

</resources>