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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 import android.util.Log;
     27 
     28 import java.util.concurrent.CountDownLatch;
     29 
     30 /** This class implements sharing the URL of the currently
     31   * shown browser page over NFC. Sharing is only active
     32   * when the activity is in the foreground and resumed.
     33   * Incognito tabs will not be shared over NFC.
     34   */
     35 public class NfcHandler implements NfcAdapter.CreateNdefMessageCallback {
     36     static final String TAG = "BrowserNfcHandler";
     37     static final int GET_PRIVATE_BROWSING_STATE_MSG = 100;
     38 
     39     final Controller mController;
     40 
     41     Tab mCurrentTab;
     42     boolean mIsPrivate;
     43     CountDownLatch mPrivateBrowsingSignal;
     44 
     45     public static void register(Activity activity, Controller controller) {
     46         NfcAdapter adapter = NfcAdapter.getDefaultAdapter(activity.getApplicationContext());
     47         if (adapter == null) {
     48             return;  // NFC not available on this device
     49         }
     50         NfcHandler handler = null;
     51         if (controller != null) {
     52             handler = new NfcHandler(controller);
     53         }
     54 
     55         adapter.setNdefPushMessageCallback(handler, activity);
     56     }
     57 
     58     public static void unregister(Activity activity) {
     59         // Passing a null controller causes us to disable
     60         // the callback and release the ref to out activity.
     61         register(activity, null);
     62     }
     63 
     64     public NfcHandler(Controller controller) {
     65         mController = controller;
     66     }
     67 
     68     final Handler mHandler = new Handler() {
     69         @Override
     70         public void handleMessage(Message msg) {
     71             if (msg.what == GET_PRIVATE_BROWSING_STATE_MSG) {
     72                 mIsPrivate = mCurrentTab.getWebView().isPrivateBrowsingEnabled();
     73                 mPrivateBrowsingSignal.countDown();
     74             }
     75         }
     76     };
     77 
     78     @Override
     79     public NdefMessage createNdefMessage(NfcEvent event) {
     80         mCurrentTab = mController.getCurrentTab();
     81         if ((mCurrentTab != null) && (mCurrentTab.getWebView() != null)) {
     82             // We can only read the WebView state on the UI thread, so post
     83             // a message and wait.
     84             mPrivateBrowsingSignal = new CountDownLatch(1);
     85             mHandler.sendMessage(mHandler.obtainMessage(GET_PRIVATE_BROWSING_STATE_MSG));
     86             try {
     87                 mPrivateBrowsingSignal.await();
     88             } catch (InterruptedException e) {
     89                 return null;
     90             }
     91         }
     92 
     93         if ((mCurrentTab == null) || mIsPrivate) {
     94             return null;
     95         }
     96 
     97         String currentUrl = mCurrentTab.getUrl();
     98         if (currentUrl != null) {
     99             try {
    100                 return new NdefMessage(NdefRecord.createUri(currentUrl));
    101             } catch (IllegalArgumentException e) {
    102                 Log.e(TAG, "IllegalArgumentException creating URI NdefRecord", e);
    103                 return null;
    104             }
    105         } else {
    106             return null;
    107         }
    108     }
    109 }
    110