CountriesActivity

import java.util.HashMap;
import java.util.Map;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.Filter;

public class CountriesActivity extends Activity {

	private static final String TAG = "CountriesActivity";

	private AutoCompleteTextView mCountriesAutocompleteTextView;
	private AutoCompleteTextView mCitiesAutoCompleteTextView;

	protected void onCreate(Bundle icicle) {
		super.onCreate(icicle);
		setContentView(R.layout.activity_countries);

		mCountriesAutocompleteTextView = (AutoCompleteTextView) findViewById(R.id.countries_list);
		mCitiesAutoCompleteTextView = (AutoCompleteTextView) findViewById(R.id.cities_list);

		ArrayAdapter<String> countriesAdapter = new ArrayAdapter<String>(this,
				android.R.layout.simple_dropdown_item_1line, COUNTRIES);

		ArrayAdapter<String> citiesAdapter = new ArrayAdapter<String>(this,
				android.R.layout.simple_dropdown_item_1line) {
			@Override
			public Filter getFilter() {
				// TODO Auto-generated method stub
				return new Filter() {

					@Override
					protected void publishResults(CharSequence constraint,
							FilterResults results) {
						Log.d(TAG, "Publishing w/" + results.count);
						String[] filteredList = (String[]) results.values;
						if (results != null && results.count > 0) {
							Log.d(TAG, "Trying to publish " + results.count);
							clear();
							for (String c : filteredList) {
								add(c);
							}
							notifyDataSetChanged();
						}
					}

					@Override
					protected FilterResults performFiltering(
							CharSequence constraint) {
						Log.d(TAG, constraint.toString());
						String selectedCountry = mCountriesAutocompleteTextView
								.getText().toString();
						String[] cities = CountriesActivity.getCities().get(
								selectedCountry);

						if (constraint != null
								&& CountriesActivity.getCities().containsKey(
										selectedCountry)) {
							Log.d(TAG, "Found");

							FilterResults filterResults = new FilterResults();
							filterResults.values = cities;
							filterResults.count = cities.length;
							return filterResults;
						} else {
							return new FilterResults();
						}
					}
				};
			}
		};

		mCountriesAutocompleteTextView.setAdapter(countriesAdapter);
		mCitiesAutoCompleteTextView.setAdapter(citiesAdapter);
	}

	private static final String[] COUNTRIES = new String[] { "France",
			"Germany" };

	private static final Map<String, String[]> getCities() {
		Map<String, String[]> cities = new HashMap<String, String[]>();
		String[] french = { "Paris", "Lyon", "Versailles" };
		String[] german = { "Berlin", "Munich", "Nuremburg" };
		cities.put("France", french);
		cities.put("Germany", german);
		return cities;
	}
}