Bai Tao | a58a875 | 2010-07-13 15:32:16 +0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2010 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License |
| 15 | */ |
| 16 | |
| 17 | package com.android.server.location; |
| 18 | |
| 19 | import java.io.IOException; |
| 20 | import java.util.ArrayList; |
| 21 | import java.util.List; |
| 22 | import java.util.Timer; |
| 23 | import java.util.TimerTask; |
| 24 | |
| 25 | import android.content.Context; |
| 26 | import android.location.Address; |
| 27 | import android.location.Country; |
| 28 | import android.location.Geocoder; |
| 29 | import android.location.Location; |
| 30 | import android.location.LocationListener; |
| 31 | import android.location.LocationManager; |
| 32 | import android.os.Bundle; |
| 33 | import android.util.Slog; |
| 34 | |
| 35 | /** |
| 36 | * This class detects which country the user currently is in through the enabled |
| 37 | * location providers and the GeoCoder |
| 38 | * <p> |
| 39 | * Use {@link #detectCountry} to start querying. If the location can not be |
| 40 | * resolved within the given time, the last known location will be used to get |
| 41 | * the user country through the GeoCoder. The IllegalStateException will be |
| 42 | * thrown if there is a ongoing query. |
| 43 | * <p> |
| 44 | * The current query can be stopped by {@link #stop()} |
| 45 | * |
| 46 | * @hide |
| 47 | */ |
| 48 | public class LocationBasedCountryDetector extends CountryDetectorBase { |
| 49 | private final static String TAG = "LocationBasedCountryDetector"; |
| 50 | private final static long QUERY_LOCATION_TIMEOUT = 1000 * 60 * 5; // 5 mins |
| 51 | |
| 52 | /** |
| 53 | * Used for canceling location query |
| 54 | */ |
| 55 | protected Timer mTimer; |
| 56 | |
| 57 | /** |
| 58 | * The thread to query the country from the GeoCoder. |
| 59 | */ |
| 60 | protected Thread mQueryThread; |
| 61 | protected List<LocationListener> mLocationListeners; |
| 62 | |
| 63 | private LocationManager mLocationManager; |
| 64 | private List<String> mEnabledProviders; |
| 65 | |
| 66 | public LocationBasedCountryDetector(Context ctx) { |
| 67 | super(ctx); |
| 68 | mLocationManager = (LocationManager) ctx.getSystemService(Context.LOCATION_SERVICE); |
| 69 | } |
| 70 | |
| 71 | /** |
| 72 | * @return the ISO 3166-1 two letters country code from the location |
| 73 | */ |
| 74 | protected String getCountryFromLocation(Location location) { |
| 75 | String country = null; |
| 76 | Geocoder geoCoder = new Geocoder(mContext); |
| 77 | try { |
| 78 | List<Address> addresses = geoCoder.getFromLocation( |
| 79 | location.getLatitude(), location.getLongitude(), 1); |
| 80 | if (addresses != null && addresses.size() > 0) { |
| 81 | country = addresses.get(0).getCountryCode(); |
| 82 | } |
| 83 | } catch (IOException e) { |
| 84 | Slog.w(TAG, "Exception occurs when getting country from location"); |
| 85 | } |
| 86 | return country; |
| 87 | } |
| 88 | |
| 89 | /** |
| 90 | * Register the listeners with the location providers |
| 91 | */ |
| 92 | protected void registerEnabledProviders(List<LocationListener> listeners) { |
| 93 | int total = listeners.size(); |
| 94 | for (int i = 0; i< total; i++) { |
| 95 | mLocationManager.requestLocationUpdates( |
| 96 | mEnabledProviders.get(i), 0, 0, listeners.get(i)); |
| 97 | } |
| 98 | } |
| 99 | |
| 100 | /** |
| 101 | * Unregister the listeners with the location providers |
| 102 | */ |
| 103 | protected void unregisterProviders(List<LocationListener> listeners) { |
| 104 | for (LocationListener listener : listeners) { |
| 105 | mLocationManager.removeUpdates(listener); |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | /** |
| 110 | * @return the last known location from all providers |
| 111 | */ |
| 112 | protected Location getLastKnownLocation() { |
| 113 | List<String> providers = mLocationManager.getAllProviders(); |
| 114 | Location bestLocation = null; |
| 115 | for (String provider : providers) { |
| 116 | Location lastKnownLocation = mLocationManager.getLastKnownLocation(provider); |
| 117 | if (lastKnownLocation != null) { |
| 118 | if (bestLocation == null || bestLocation.getTime() < lastKnownLocation.getTime()) { |
| 119 | bestLocation = lastKnownLocation; |
| 120 | } |
| 121 | } |
| 122 | } |
| 123 | return bestLocation; |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * @return the timeout for querying the location. |
| 128 | */ |
| 129 | protected long getQueryLocationTimeout() { |
| 130 | return QUERY_LOCATION_TIMEOUT; |
| 131 | } |
| 132 | |
| 133 | /** |
| 134 | * @return the total number of enabled location providers |
| 135 | */ |
| 136 | protected int getTotalEnabledProviders() { |
| 137 | if (mEnabledProviders == null) { |
| 138 | mEnabledProviders = mLocationManager.getProviders(true); |
| 139 | } |
| 140 | return mEnabledProviders.size(); |
| 141 | } |
| 142 | |
| 143 | /** |
| 144 | * Start detecting the country. |
| 145 | * <p> |
| 146 | * Queries the location from all location providers, then starts a thread to query the |
| 147 | * country from GeoCoder. |
| 148 | */ |
| 149 | @Override |
| 150 | public synchronized Country detectCountry() { |
| 151 | if (mLocationListeners != null) { |
| 152 | throw new IllegalStateException(); |
| 153 | } |
| 154 | // Request the location from all enabled providers. |
| 155 | int totalProviders = getTotalEnabledProviders(); |
| 156 | if (totalProviders > 0) { |
| 157 | mLocationListeners = new ArrayList<LocationListener>(totalProviders); |
| 158 | for (int i = 0; i < totalProviders; i++) { |
| 159 | LocationListener listener = new LocationListener () { |
| 160 | public void onLocationChanged(Location location) { |
| 161 | if (location != null) { |
| 162 | LocationBasedCountryDetector.this.stop(); |
| 163 | queryCountryCode(location); |
| 164 | } |
| 165 | } |
| 166 | public void onProviderDisabled(String provider) { |
| 167 | } |
| 168 | public void onProviderEnabled(String provider) { |
| 169 | } |
| 170 | public void onStatusChanged(String provider, int status, Bundle extras) { |
| 171 | } |
| 172 | }; |
| 173 | mLocationListeners.add(listener); |
| 174 | } |
| 175 | registerEnabledProviders(mLocationListeners); |
| 176 | mTimer = new Timer(); |
| 177 | mTimer.schedule(new TimerTask() { |
| 178 | @Override |
| 179 | public void run() { |
| 180 | mTimer = null; |
| 181 | LocationBasedCountryDetector.this.stop(); |
| 182 | // Looks like no provider could provide the location, let's try the last |
| 183 | // known location. |
| 184 | queryCountryCode(getLastKnownLocation()); |
| 185 | } |
| 186 | }, getQueryLocationTimeout()); |
| 187 | } else { |
| 188 | // There is no provider enabled. |
| 189 | queryCountryCode(getLastKnownLocation()); |
| 190 | } |
| 191 | return mDetectedCountry; |
| 192 | } |
| 193 | |
| 194 | /** |
| 195 | * Stop the current query without notifying the listener. |
| 196 | */ |
| 197 | @Override |
| 198 | public synchronized void stop() { |
| 199 | if (mLocationListeners != null) { |
| 200 | unregisterProviders(mLocationListeners); |
| 201 | mLocationListeners = null; |
| 202 | } |
| 203 | if (mTimer != null) { |
| 204 | mTimer.cancel(); |
| 205 | mTimer = null; |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | /** |
| 210 | * Start a new thread to query the country from Geocoder. |
| 211 | */ |
| 212 | private synchronized void queryCountryCode(final Location location) { |
| 213 | if (location == null) { |
| 214 | notifyListener(null); |
| 215 | return; |
| 216 | } |
| 217 | if (mQueryThread != null) return; |
| 218 | mQueryThread = new Thread(new Runnable() { |
| 219 | public void run() { |
| 220 | String countryIso = null; |
| 221 | if (location != null) { |
| 222 | countryIso = getCountryFromLocation(location); |
| 223 | } |
| 224 | if (countryIso != null) { |
| 225 | mDetectedCountry = new Country(countryIso, Country.COUNTRY_SOURCE_LOCATION); |
| 226 | } else { |
| 227 | mDetectedCountry = null; |
| 228 | } |
| 229 | notifyListener(mDetectedCountry); |
| 230 | mQueryThread = null; |
| 231 | } |
| 232 | }); |
| 233 | mQueryThread.start(); |
| 234 | } |
| 235 | } |