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      1 /*
      2  * Copyright (C) 2011 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.browser;
     18 
     19 import android.app.Activity;
     20 import android.nfc.NdefMessage;
     21 import android.nfc.NdefRecord;
     22 import android.nfc.NfcAdapter;
     23 import android.nfc.NfcEvent;
     24 import android.os.Handler;
     25 import android.os.Message;
     26 
     27 import java.util.concurrent.CountDownLatch;
     28 
     29 /** This class implements sharing the URL of the currently
     30   * shown browser page over NFC. Sharing is only active
     31   * when the activity is in the foreground and resumed.
     32   * Incognito tabs will not be shared over NFC.
     33   */
     34 public class NfcHandler implements NfcAdapter.CreateNdefMessageCallback {
     35     static final int GET_PRIVATE_BROWSING_STATE_MSG = 100;
     36 
     37     final Controller mController;
     38 
     39     Tab mCurrentTab;
     40     boolean mIsPrivate;
     41     CountDownLatch mPrivateBrowsingSignal;
     42 
     43     public static void register(Activity activity, Controller controller) {
     44         NfcAdapter adapter = NfcAdapter.getDefaultAdapter(activity.getApplicationContext());
     45         if (adapter == null) {
     46             return;  // NFC not available on this device
     47         }
     48         NfcHandler handler = null;
     49         if (controller != null) {
     50             handler = new NfcHandler(controller);
     51         }
     52 
     53         adapter.setNdefPushMessageCallback(handler, activity);
     54     }
     55 
     56     public static void unregister(Activity activity) {
     57         // Passing a null controller causes us to disable
     58         // the callback and release the ref to out activity.
     59         register(activity, null);
     60     }
     61 
     62     public NfcHandler(Controller controller) {
     63         mController = controller;
     64     }
     65 
     66     final Handler mHandler = new Handler() {
     67         @Override
     68         public void handleMessage(Message msg) {
     69             if (msg.what == GET_PRIVATE_BROWSING_STATE_MSG) {
     70                 mIsPrivate = mCurrentTab.getWebView().isPrivateBrowsingEnabled();
     71                 mPrivateBrowsingSignal.countDown();
     72             }
     73         }
     74     };
     75 
     76     @Override
     77     public NdefMessage createNdefMessage(NfcEvent event) {
     78         mCurrentTab = mController.getCurrentTab();
     79         if ((mCurrentTab != null) && (mCurrentTab.getWebView() != null)) {
     80             // We can only read the WebView state on the UI thread, so post
     81             // a message and wait.
     82             mPrivateBrowsingSignal = new CountDownLatch(1);
     83             mHandler.sendMessage(mHandler.obtainMessage(GET_PRIVATE_BROWSING_STATE_MSG));
     84             try {
     85                 mPrivateBrowsingSignal.await();
     86             } catch (InterruptedException e) {
     87                 return null;
     88             }
     89         }
     90 
     91         if ((mCurrentTab == null) || mIsPrivate) {
     92             return null;
     93         }
     94 
     95         String currentUrl = mCurrentTab.getUrl();
     96         if (currentUrl != null) {
     97             NdefRecord record = NdefRecord.createUri(currentUrl);
     98             NdefMessage msg = new NdefMessage(new NdefRecord[] { record });
     99             return msg;
    100         } else {
    101             return null;
    102         }
    103     }
    104 }
    105