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      1 /*
      2  * Copyright (C) 2013 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.wifi;
     18 
     19 import android.app.Notification;
     20 import android.app.NotificationManager;
     21 import android.app.TaskStackBuilder;
     22 import android.content.BroadcastReceiver;
     23 import android.content.ContentResolver;
     24 import android.content.Context;
     25 import android.content.Intent;
     26 import android.content.IntentFilter;
     27 import android.database.ContentObserver;
     28 import android.net.NetworkInfo;
     29 import android.net.wifi.ScanResult;
     30 import android.net.wifi.WifiManager;
     31 import android.os.Handler;
     32 import android.os.Message;
     33 import android.os.UserHandle;
     34 import android.provider.Settings;
     35 
     36 import java.io.FileDescriptor;
     37 import java.io.PrintWriter;
     38 import java.util.List;
     39 
     40 /* Takes care of handling the "open wi-fi network available" notification @hide */
     41 final class WifiNotificationController {
     42     /**
     43      * The icon to show in the 'available networks' notification. This will also
     44      * be the ID of the Notification given to the NotificationManager.
     45      */
     46     private static final int ICON_NETWORKS_AVAILABLE =
     47             com.android.internal.R.drawable.stat_notify_wifi_in_range;
     48     /**
     49      * When a notification is shown, we wait this amount before possibly showing it again.
     50      */
     51     private final long NOTIFICATION_REPEAT_DELAY_MS;
     52     /**
     53      * Whether the user has set the setting to show the 'available networks' notification.
     54      */
     55     private boolean mNotificationEnabled;
     56     /**
     57      * Observes the user setting to keep {@link #mNotificationEnabled} in sync.
     58      */
     59     private NotificationEnabledSettingObserver mNotificationEnabledSettingObserver;
     60     /**
     61      * The {@link System#currentTimeMillis()} must be at least this value for us
     62      * to show the notification again.
     63      */
     64     private long mNotificationRepeatTime;
     65     /**
     66      * The Notification object given to the NotificationManager.
     67      */
     68     private Notification mNotification;
     69     /**
     70      * Whether the notification is being shown, as set by us. That is, if the
     71      * user cancels the notification, we will not receive the callback so this
     72      * will still be true. We only guarantee if this is false, then the
     73      * notification is not showing.
     74      */
     75     private boolean mNotificationShown;
     76     /**
     77      * The number of continuous scans that must occur before consider the
     78      * supplicant in a scanning state. This allows supplicant to associate with
     79      * remembered networks that are in the scan results.
     80      */
     81     private static final int NUM_SCANS_BEFORE_ACTUALLY_SCANNING = 3;
     82     /**
     83      * The number of scans since the last network state change. When this
     84      * exceeds {@link #NUM_SCANS_BEFORE_ACTUALLY_SCANNING}, we consider the
     85      * supplicant to actually be scanning. When the network state changes to
     86      * something other than scanning, we reset this to 0.
     87      */
     88     private int mNumScansSinceNetworkStateChange;
     89 
     90     private final Context mContext;
     91     private final WifiStateMachine mWifiStateMachine;
     92     private NetworkInfo mNetworkInfo;
     93     private volatile int mWifiState;
     94 
     95     WifiNotificationController(Context context, WifiStateMachine wsm) {
     96         mContext = context;
     97         mWifiStateMachine = wsm;
     98         mWifiState = WifiManager.WIFI_STATE_UNKNOWN;
     99 
    100         IntentFilter filter = new IntentFilter();
    101         filter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
    102         filter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
    103         filter.addAction(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
    104 
    105         mContext.registerReceiver(
    106                 new BroadcastReceiver() {
    107                     @Override
    108                     public void onReceive(Context context, Intent intent) {
    109                         if (intent.getAction().equals(WifiManager.WIFI_STATE_CHANGED_ACTION)) {
    110                             mWifiState = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE,
    111                                     WifiManager.WIFI_STATE_UNKNOWN);
    112                             resetNotification();
    113                         } else if (intent.getAction().equals(
    114                                 WifiManager.NETWORK_STATE_CHANGED_ACTION)) {
    115                             mNetworkInfo = (NetworkInfo) intent.getParcelableExtra(
    116                                     WifiManager.EXTRA_NETWORK_INFO);
    117                             // reset & clear notification on a network connect & disconnect
    118                             switch(mNetworkInfo.getDetailedState()) {
    119                                 case CONNECTED:
    120                                 case DISCONNECTED:
    121                                 case CAPTIVE_PORTAL_CHECK:
    122                                     resetNotification();
    123                                     break;
    124                             }
    125                         } else if (intent.getAction().equals(
    126                                 WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)) {
    127                             checkAndSetNotification(mNetworkInfo,
    128                                     mWifiStateMachine.syncGetScanResultsList());
    129                         }
    130                     }
    131                 }, filter);
    132 
    133         // Setting is in seconds
    134         NOTIFICATION_REPEAT_DELAY_MS = Settings.Global.getInt(context.getContentResolver(),
    135                 Settings.Global.WIFI_NETWORKS_AVAILABLE_REPEAT_DELAY, 900) * 1000l;
    136         mNotificationEnabledSettingObserver = new NotificationEnabledSettingObserver(new Handler());
    137         mNotificationEnabledSettingObserver.register();
    138     }
    139 
    140     private synchronized void checkAndSetNotification(NetworkInfo networkInfo,
    141             List<ScanResult> scanResults) {
    142 
    143         // TODO: unregister broadcast so we do not have to check here
    144         // If we shouldn't place a notification on available networks, then
    145         // don't bother doing any of the following
    146         if (!mNotificationEnabled) return;
    147         if (mWifiState != WifiManager.WIFI_STATE_ENABLED) return;
    148 
    149         NetworkInfo.State state = NetworkInfo.State.DISCONNECTED;
    150         if (networkInfo != null)
    151             state = networkInfo.getState();
    152 
    153         if ((state == NetworkInfo.State.DISCONNECTED)
    154                 || (state == NetworkInfo.State.UNKNOWN)) {
    155             if (scanResults != null) {
    156                 int numOpenNetworks = 0;
    157                 for (int i = scanResults.size() - 1; i >= 0; i--) {
    158                     ScanResult scanResult = scanResults.get(i);
    159 
    160                     //A capability of [ESS] represents an open access point
    161                     //that is available for an STA to connect
    162                     if (scanResult.capabilities != null &&
    163                             scanResult.capabilities.equals("[ESS]")) {
    164                         numOpenNetworks++;
    165                     }
    166                 }
    167 
    168                 if (numOpenNetworks > 0) {
    169                     if (++mNumScansSinceNetworkStateChange >= NUM_SCANS_BEFORE_ACTUALLY_SCANNING) {
    170                         /*
    171                          * We've scanned continuously at least
    172                          * NUM_SCANS_BEFORE_NOTIFICATION times. The user
    173                          * probably does not have a remembered network in range,
    174                          * since otherwise supplicant would have tried to
    175                          * associate and thus resetting this counter.
    176                          */
    177                         setNotificationVisible(true, numOpenNetworks, false, 0);
    178                     }
    179                     return;
    180                 }
    181             }
    182         }
    183 
    184         // No open networks in range, remove the notification
    185         setNotificationVisible(false, 0, false, 0);
    186     }
    187 
    188     /**
    189      * Clears variables related to tracking whether a notification has been
    190      * shown recently and clears the current notification.
    191      */
    192     private synchronized void resetNotification() {
    193         mNotificationRepeatTime = 0;
    194         mNumScansSinceNetworkStateChange = 0;
    195         setNotificationVisible(false, 0, false, 0);
    196     }
    197 
    198     /**
    199      * Display or don't display a notification that there are open Wi-Fi networks.
    200      * @param visible {@code true} if notification should be visible, {@code false} otherwise
    201      * @param numNetworks the number networks seen
    202      * @param force {@code true} to force notification to be shown/not-shown,
    203      * even if it is already shown/not-shown.
    204      * @param delay time in milliseconds after which the notification should be made
    205      * visible or invisible.
    206      */
    207     private void setNotificationVisible(boolean visible, int numNetworks, boolean force,
    208             int delay) {
    209 
    210         // Since we use auto cancel on the notification, when the
    211         // mNetworksAvailableNotificationShown is true, the notification may
    212         // have actually been canceled.  However, when it is false we know
    213         // for sure that it is not being shown (it will not be shown any other
    214         // place than here)
    215 
    216         // If it should be hidden and it is already hidden, then noop
    217         if (!visible && !mNotificationShown && !force) {
    218             return;
    219         }
    220 
    221         NotificationManager notificationManager = (NotificationManager) mContext
    222                 .getSystemService(Context.NOTIFICATION_SERVICE);
    223 
    224         Message message;
    225         if (visible) {
    226 
    227             // Not enough time has passed to show the notification again
    228             if (System.currentTimeMillis() < mNotificationRepeatTime) {
    229                 return;
    230             }
    231 
    232             if (mNotification == null) {
    233                 // Cache the Notification object.
    234                 mNotification = new Notification();
    235                 mNotification.when = 0;
    236                 mNotification.icon = ICON_NETWORKS_AVAILABLE;
    237                 mNotification.flags = Notification.FLAG_AUTO_CANCEL;
    238                 mNotification.contentIntent = TaskStackBuilder.create(mContext)
    239                         .addNextIntentWithParentStack(
    240                                 new Intent(WifiManager.ACTION_PICK_WIFI_NETWORK))
    241                         .getPendingIntent(0, 0, null, UserHandle.CURRENT);
    242             }
    243 
    244             CharSequence title = mContext.getResources().getQuantityText(
    245                     com.android.internal.R.plurals.wifi_available, numNetworks);
    246             CharSequence details = mContext.getResources().getQuantityText(
    247                     com.android.internal.R.plurals.wifi_available_detailed, numNetworks);
    248             mNotification.tickerText = title;
    249             mNotification.color = mContext.getResources().getColor(
    250                     com.android.internal.R.color.system_notification_accent_color);
    251             mNotification.setLatestEventInfo(mContext, title, details, mNotification.contentIntent);
    252 
    253             mNotificationRepeatTime = System.currentTimeMillis() + NOTIFICATION_REPEAT_DELAY_MS;
    254 
    255             notificationManager.notifyAsUser(null, ICON_NETWORKS_AVAILABLE, mNotification,
    256                     UserHandle.ALL);
    257         } else {
    258             notificationManager.cancelAsUser(null, ICON_NETWORKS_AVAILABLE, UserHandle.ALL);
    259         }
    260 
    261         mNotificationShown = visible;
    262     }
    263 
    264     void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
    265         pw.println("mNotificationEnabled " + mNotificationEnabled);
    266         pw.println("mNotificationRepeatTime " + mNotificationRepeatTime);
    267         pw.println("mNotificationShown " + mNotificationShown);
    268         pw.println("mNumScansSinceNetworkStateChange " + mNumScansSinceNetworkStateChange);
    269     }
    270 
    271     private class NotificationEnabledSettingObserver extends ContentObserver {
    272         public NotificationEnabledSettingObserver(Handler handler) {
    273             super(handler);
    274         }
    275 
    276         public void register() {
    277             ContentResolver cr = mContext.getContentResolver();
    278             cr.registerContentObserver(Settings.Global.getUriFor(
    279                     Settings.Global.WIFI_NETWORKS_AVAILABLE_NOTIFICATION_ON), true, this);
    280             synchronized (WifiNotificationController.this) {
    281                 mNotificationEnabled = getValue();
    282             }
    283         }
    284 
    285         @Override
    286         public void onChange(boolean selfChange) {
    287             super.onChange(selfChange);
    288 
    289             synchronized (WifiNotificationController.this) {
    290                 mNotificationEnabled = getValue();
    291                 resetNotification();
    292             }
    293         }
    294 
    295         private boolean getValue() {
    296             return Settings.Global.getInt(mContext.getContentResolver(),
    297                     Settings.Global.WIFI_NETWORKS_AVAILABLE_NOTIFICATION_ON, 1) == 1;
    298         }
    299     }
    300 
    301 }
    302