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