1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
5 * use this file except in compliance with the License. You may obtain a copy of
6 * 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, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations under
14 * the License.
15 */
16
17package android.location;
18
19import java.util.HashMap;
20
21import android.annotation.SystemService;
22import android.content.Context;
23import android.os.Handler;
24import android.os.Looper;
25import android.os.RemoteException;
26import android.util.Log;
27
28/**
29 * This class provides access to the system country detector service. This
30 * service allows applications to obtain the country that the user is in.
31 * <p>
32 * The country will be detected in order of reliability, like
33 * <ul>
34 * <li>Mobile network</li>
35 * <li>Location</li>
36 * <li>SIM's country</li>
37 * <li>Phone's locale</li>
38 * </ul>
39 * <p>
40 * Call the {@link #detectCountry()} to get the available country immediately.
41 * <p>
42 * To be notified of the future country change, use the
43 * {@link #addCountryListener}
44 * <p>
45 *
46 * @hide
47 */
48@SystemService(Context.COUNTRY_DETECTOR)
49public class CountryDetector {
50
51    /**
52     * The class to wrap the ICountryListener.Stub and CountryListener objects
53     * together. The CountryListener will be notified through the specific
54     * looper once the country changed and detected.
55     */
56    private final static class ListenerTransport extends ICountryListener.Stub {
57
58        private final CountryListener mListener;
59
60        private final Handler mHandler;
61
62        public ListenerTransport(CountryListener listener, Looper looper) {
63            mListener = listener;
64            if (looper != null) {
65                mHandler = new Handler(looper);
66            } else {
67                mHandler = new Handler();
68            }
69        }
70
71        public void onCountryDetected(final Country country) {
72            mHandler.post(new Runnable() {
73                public void run() {
74                    mListener.onCountryDetected(country);
75                }
76            });
77        }
78    }
79
80    private final static String TAG = "CountryDetector";
81    private final ICountryDetector mService;
82    private final HashMap<CountryListener, ListenerTransport> mListeners;
83
84    /**
85     * @hide - hide this constructor because it has a parameter of type
86     *       ICountryDetector, which is a system private class. The right way to
87     *       create an instance of this class is using the factory
88     *       Context.getSystemService.
89     */
90    public CountryDetector(ICountryDetector service) {
91        mService = service;
92        mListeners = new HashMap<CountryListener, ListenerTransport>();
93    }
94
95    /**
96     * Start detecting the country that the user is in.
97     *
98     * @return the country if it is available immediately, otherwise null will
99     *         be returned.
100     */
101    public Country detectCountry() {
102        try {
103            return mService.detectCountry();
104        } catch (RemoteException e) {
105            Log.e(TAG, "detectCountry: RemoteException", e);
106            return null;
107        }
108    }
109
110    /**
111     * Add a listener to receive the notification when the country is detected
112     * or changed.
113     *
114     * @param listener will be called when the country is detected or changed.
115     * @param looper a Looper object whose message queue will be used to
116     *        implement the callback mechanism. If looper is null then the
117     *        callbacks will be called on the main thread.
118     */
119    public void addCountryListener(CountryListener listener, Looper looper) {
120        synchronized (mListeners) {
121            if (!mListeners.containsKey(listener)) {
122                ListenerTransport transport = new ListenerTransport(listener, looper);
123                try {
124                    mService.addCountryListener(transport);
125                    mListeners.put(listener, transport);
126                } catch (RemoteException e) {
127                    Log.e(TAG, "addCountryListener: RemoteException", e);
128                }
129            }
130        }
131    }
132
133    /**
134     * Remove the listener
135     */
136    public void removeCountryListener(CountryListener listener) {
137        synchronized (mListeners) {
138            ListenerTransport transport = mListeners.get(listener);
139            if (transport != null) {
140                try {
141                    mListeners.remove(listener);
142                    mService.removeCountryListener(transport);
143                } catch (RemoteException e) {
144                    Log.e(TAG, "removeCountryListener: RemoteException", e);
145                }
146            }
147        }
148    }
149}
150