1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  * Copyright (C) 2016 Mopria Alliance, Inc.
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  *      http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17 
18 package com.android.bips.util;
19 
20 import android.content.BroadcastReceiver;
21 import android.content.Context;
22 import android.content.Intent;
23 import android.content.IntentFilter;
24 import android.net.ConnectivityManager;
25 import android.net.Network;
26 import android.net.NetworkInfo;
27 import android.util.Log;
28 
29 /** Reliably reports on changes to Wi-Fi connectivity state */
30 public class WifiMonitor implements AutoCloseable {
31     private static final String TAG = WifiMonitor.class.getSimpleName();
32     private static final boolean DEBUG = false;
33 
34     private final Context mContext;
35     private final Listener mListener;
36 
37     // Current connectivity state or null if not known yet
38     private Boolean mConnected;
39 
40     public interface Listener {
onConnectionStateChanged(boolean isConnected)41         void onConnectionStateChanged(boolean isConnected);
42     }
43 
44     private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
45         @Override
46         public void onReceive(Context context, Intent intent) {
47             if (ConnectivityManager.CONNECTIVITY_ACTION.equals(intent.getAction())) {
48                 boolean isConnected = isConnected(context);
49                 if (mConnected == null || mConnected != isConnected) {
50                     mConnected = isConnected;
51                     mListener.onConnectionStateChanged(mConnected);
52                 }
53             }
54         }
55     };
56 
57     /**
58      * Begin listening for connectivity changes, signalling the current WiFi
59      * connectivity state and any subsequent state changes to the listener.
60      */
WifiMonitor(Context context, Listener listener)61     public WifiMonitor(Context context, Listener listener) {
62         if (DEBUG) Log.d(TAG, "WifiMonitor()");
63         mListener = listener;
64         mContext = context;
65         IntentFilter filter = new IntentFilter();
66         filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
67         mContext.registerReceiver(mBroadcastReceiver, filter);
68     }
69 
70     /** Return the current connectivity state */
isConnected(Context context)71     public static boolean isConnected(Context context) {
72         ConnectivityManager cm =
73                 (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
74 
75         for (Network network : cm.getAllNetworks()) {
76             NetworkInfo networkInfo = cm.getNetworkInfo(network);
77             if (networkInfo != null && networkInfo.isConnected() &&
78                     networkInfo.getType() == ConnectivityManager.TYPE_WIFI) {
79                 return true;
80             }
81         }
82         return false;
83     }
84 
85     /**
86      * Stop listening for connectivity state
87      */
88     @Override
close()89     public void close() {
90         if (DEBUG) Log.d(TAG, "close()");
91         if (mBroadcastReceiver != null) {
92             mContext.unregisterReceiver(mBroadcastReceiver);
93             mBroadcastReceiver = null;
94         }
95     }
96 
97     /** A factory for creating instances of this object (needed for unit tests) */
98     public static class Factory {
create(Context context, Listener listener)99         public WifiMonitor create(Context context, Listener listener) {
100             return new WifiMonitor(context, listener);
101         }
102     }
103 }