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 
register(Activity activity, Controller controller)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 
unregister(Activity activity)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 
NfcHandler(Controller controller)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
createNdefMessage(NfcEvent event)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