1 /*
2  * Copyright (C) 2010 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 android.nfc;
18 
19 import android.annotation.RequiresPermission;
20 import android.annotation.SdkConstant;
21 import android.annotation.SdkConstant.SdkConstantType;
22 import android.annotation.SystemApi;
23 import android.app.Activity;
24 import android.app.ActivityThread;
25 import android.app.OnActivityPausedListener;
26 import android.app.PendingIntent;
27 import android.content.Context;
28 import android.content.IntentFilter;
29 import android.content.pm.IPackageManager;
30 import android.content.pm.PackageManager;
31 import android.net.Uri;
32 import android.nfc.tech.MifareClassic;
33 import android.nfc.tech.Ndef;
34 import android.nfc.tech.NfcA;
35 import android.nfc.tech.NfcF;
36 import android.os.Bundle;
37 import android.os.Handler;
38 import android.os.IBinder;
39 import android.os.RemoteException;
40 import android.os.ServiceManager;
41 import android.util.Log;
42 
43 import java.io.IOException;
44 import java.util.HashMap;
45 
46 /**
47  * Represents the local NFC adapter.
48  * <p>
49  * Use the helper {@link #getDefaultAdapter(Context)} to get the default NFC
50  * adapter for this Android device.
51  *
52  * <div class="special reference">
53  * <h3>Developer Guides</h3>
54  * <p>For more information about using NFC, read the
55  * <a href="{@docRoot}guide/topics/nfc/index.html">Near Field Communication</a> developer guide.</p>
56  * <p>To perform basic file sharing between devices, read
57  * <a href="{@docRoot}training/beam-files/index.html">Sharing Files with NFC</a>.
58  * </div>
59  */
60 public final class NfcAdapter {
61     static final String TAG = "NFC";
62 
63     /**
64      * Intent to start an activity when a tag with NDEF payload is discovered.
65      *
66      * <p>The system inspects the first {@link NdefRecord} in the first {@link NdefMessage} and
67      * looks for a URI, SmartPoster, or MIME record. If a URI or SmartPoster record is found the
68      * intent will contain the URI in its data field. If a MIME record is found the intent will
69      * contain the MIME type in its type field. This allows activities to register
70      * {@link IntentFilter}s targeting specific content on tags. Activities should register the
71      * most specific intent filters possible to avoid the activity chooser dialog, which can
72      * disrupt the interaction with the tag as the user interacts with the screen.
73      *
74      * <p>If the tag has an NDEF payload this intent is started before
75      * {@link #ACTION_TECH_DISCOVERED}. If any activities respond to this intent neither
76      * {@link #ACTION_TECH_DISCOVERED} or {@link #ACTION_TAG_DISCOVERED} will be started.
77      *
78      * <p>The MIME type or data URI of this intent are normalized before dispatch -
79      * so that MIME, URI scheme and URI host are always lower-case.
80      */
81     @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
82     public static final String ACTION_NDEF_DISCOVERED = "android.nfc.action.NDEF_DISCOVERED";
83 
84     /**
85      * Intent to start an activity when a tag is discovered and activities are registered for the
86      * specific technologies on the tag.
87      *
88      * <p>To receive this intent an activity must include an intent filter
89      * for this action and specify the desired tech types in a
90      * manifest <code>meta-data</code> entry. Here is an example manfiest entry:
91      * <pre>
92      * &lt;activity android:name=".nfc.TechFilter" android:label="NFC/TechFilter"&gt;
93      *     &lt;!-- Add a technology filter --&gt;
94      *     &lt;intent-filter&gt;
95      *         &lt;action android:name="android.nfc.action.TECH_DISCOVERED" /&gt;
96      *     &lt;/intent-filter&gt;
97      *
98      *     &lt;meta-data android:name="android.nfc.action.TECH_DISCOVERED"
99      *         android:resource="@xml/filter_nfc"
100      *     /&gt;
101      * &lt;/activity&gt;</pre>
102      *
103      * <p>The meta-data XML file should contain one or more <code>tech-list</code> entries
104      * each consisting or one or more <code>tech</code> entries. The <code>tech</code> entries refer
105      * to the qualified class name implementing the technology, for example "android.nfc.tech.NfcA".
106      *
107      * <p>A tag matches if any of the
108      * <code>tech-list</code> sets is a subset of {@link Tag#getTechList() Tag.getTechList()}. Each
109      * of the <code>tech-list</code>s is considered independently and the
110      * activity is considered a match is any single <code>tech-list</code> matches the tag that was
111      * discovered. This provides AND and OR semantics for filtering desired techs. Here is an
112      * example that will match any tag using {@link NfcF} or any tag using {@link NfcA},
113      * {@link MifareClassic}, and {@link Ndef}:
114      *
115      * <pre>
116      * &lt;resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2"&gt;
117      *     &lt;!-- capture anything using NfcF --&gt;
118      *     &lt;tech-list&gt;
119      *         &lt;tech&gt;android.nfc.tech.NfcF&lt;/tech&gt;
120      *     &lt;/tech-list&gt;
121      *
122      *     &lt;!-- OR --&gt;
123      *
124      *     &lt;!-- capture all MIFARE Classics with NDEF payloads --&gt;
125      *     &lt;tech-list&gt;
126      *         &lt;tech&gt;android.nfc.tech.NfcA&lt;/tech&gt;
127      *         &lt;tech&gt;android.nfc.tech.MifareClassic&lt;/tech&gt;
128      *         &lt;tech&gt;android.nfc.tech.Ndef&lt;/tech&gt;
129      *     &lt;/tech-list&gt;
130      * &lt;/resources&gt;</pre>
131      *
132      * <p>This intent is started after {@link #ACTION_NDEF_DISCOVERED} and before
133      * {@link #ACTION_TAG_DISCOVERED}. If any activities respond to {@link #ACTION_NDEF_DISCOVERED}
134      * this intent will not be started. If any activities respond to this intent
135      * {@link #ACTION_TAG_DISCOVERED} will not be started.
136      */
137     @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
138     public static final String ACTION_TECH_DISCOVERED = "android.nfc.action.TECH_DISCOVERED";
139 
140     /**
141      * Intent to start an activity when a tag is discovered.
142      *
143      * <p>This intent will not be started when a tag is discovered if any activities respond to
144      * {@link #ACTION_NDEF_DISCOVERED} or {@link #ACTION_TECH_DISCOVERED} for the current tag.
145      */
146     @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
147     public static final String ACTION_TAG_DISCOVERED = "android.nfc.action.TAG_DISCOVERED";
148 
149     /**
150      * Broadcast Action: Intent to notify an application that an transaction event has occurred
151      * on the Secure Element.
152      *
153      * <p>This intent will only be sent if the application has requested permission for
154      * {@link android.Manifest.permission#NFC_TRANSACTION_EVENT} and if the application has the
155      * necessary access to Secure Element which witnessed the particular event.
156      */
157     @RequiresPermission(android.Manifest.permission.NFC_TRANSACTION_EVENT)
158     @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
159     public static final String ACTION_TRANSACTION_DETECTED =
160             "android.nfc.action.TRANSACTION_DETECTED";
161 
162     /**
163      * Broadcast to only the activity that handles ACTION_TAG_DISCOVERED
164      * @hide
165      */
166     public static final String ACTION_TAG_LEFT_FIELD = "android.nfc.action.TAG_LOST";
167 
168     /**
169      * Mandatory extra containing the {@link Tag} that was discovered for the
170      * {@link #ACTION_NDEF_DISCOVERED}, {@link #ACTION_TECH_DISCOVERED}, and
171      * {@link #ACTION_TAG_DISCOVERED} intents.
172      */
173     public static final String EXTRA_TAG = "android.nfc.extra.TAG";
174 
175     /**
176      * Extra containing an array of {@link NdefMessage} present on the discovered tag.<p>
177      * This extra is mandatory for {@link #ACTION_NDEF_DISCOVERED} intents,
178      * and optional for {@link #ACTION_TECH_DISCOVERED}, and
179      * {@link #ACTION_TAG_DISCOVERED} intents.<p>
180      * When this extra is present there will always be at least one
181      * {@link NdefMessage} element. Most NDEF tags have only one NDEF message,
182      * but we use an array for future compatibility.
183      */
184     public static final String EXTRA_NDEF_MESSAGES = "android.nfc.extra.NDEF_MESSAGES";
185 
186     /**
187      * Optional extra containing a byte array containing the ID of the discovered tag for
188      * the {@link #ACTION_NDEF_DISCOVERED}, {@link #ACTION_TECH_DISCOVERED}, and
189      * {@link #ACTION_TAG_DISCOVERED} intents.
190      */
191     public static final String EXTRA_ID = "android.nfc.extra.ID";
192 
193     /**
194      * Broadcast Action: The state of the local NFC adapter has been
195      * changed.
196      * <p>For example, NFC has been turned on or off.
197      * <p>Always contains the extra field {@link #EXTRA_ADAPTER_STATE}
198      */
199     @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
200     public static final String ACTION_ADAPTER_STATE_CHANGED =
201             "android.nfc.action.ADAPTER_STATE_CHANGED";
202 
203     /**
204      * Used as an int extra field in {@link #ACTION_ADAPTER_STATE_CHANGED}
205      * intents to request the current power state. Possible values are:
206      * {@link #STATE_OFF},
207      * {@link #STATE_TURNING_ON},
208      * {@link #STATE_ON},
209      * {@link #STATE_TURNING_OFF},
210      */
211     public static final String EXTRA_ADAPTER_STATE = "android.nfc.extra.ADAPTER_STATE";
212 
213     /**
214      * Mandatory byte[] extra field in {@link #ACTION_TRANSACTION_DETECTED}
215      */
216     public static final String EXTRA_AID = "android.nfc.extra.AID";
217 
218     /**
219      * Optional byte[] extra field in {@link #ACTION_TRANSACTION_DETECTED}
220      */
221     public static final String EXTRA_DATA = "android.nfc.extra.DATA";
222 
223     /**
224      * Mandatory String extra field in {@link #ACTION_TRANSACTION_DETECTED}
225      * Indicates the Secure Element on which the transaction occurred.
226      * eSE1...eSEn for Embedded Secure Elements, SIM1...SIMn for UICC, etc.
227      */
228     public static final String EXTRA_SECURE_ELEMENT_NAME = "android.nfc.extra.SECURE_ELEMENT_NAME";
229 
230     public static final int STATE_OFF = 1;
231     public static final int STATE_TURNING_ON = 2;
232     public static final int STATE_ON = 3;
233     public static final int STATE_TURNING_OFF = 4;
234 
235     /**
236      * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
237      * <p>
238      * Setting this flag enables polling for Nfc-A technology.
239      */
240     public static final int FLAG_READER_NFC_A = 0x1;
241 
242     /**
243      * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
244      * <p>
245      * Setting this flag enables polling for Nfc-B technology.
246      */
247     public static final int FLAG_READER_NFC_B = 0x2;
248 
249     /**
250      * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
251      * <p>
252      * Setting this flag enables polling for Nfc-F technology.
253      */
254     public static final int FLAG_READER_NFC_F = 0x4;
255 
256     /**
257      * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
258      * <p>
259      * Setting this flag enables polling for Nfc-V (ISO15693) technology.
260      */
261     public static final int FLAG_READER_NFC_V = 0x8;
262 
263     /**
264      * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
265      * <p>
266      * Setting this flag enables polling for NfcBarcode technology.
267      */
268     public static final int FLAG_READER_NFC_BARCODE = 0x10;
269 
270     /**
271      * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
272      * <p>
273      * Setting this flag allows the caller to prevent the
274      * platform from performing an NDEF check on the tags it
275      * finds.
276      */
277     public static final int FLAG_READER_SKIP_NDEF_CHECK = 0x80;
278 
279     /**
280      * Flag for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
281      * <p>
282      * Setting this flag allows the caller to prevent the
283      * platform from playing sounds when it discovers a tag.
284      */
285     public static final int FLAG_READER_NO_PLATFORM_SOUNDS = 0x100;
286 
287     /**
288      * Int Extra for use with {@link #enableReaderMode(Activity, ReaderCallback, int, Bundle)}.
289      * <p>
290      * Setting this integer extra allows the calling application to specify
291      * the delay that the platform will use for performing presence checks
292      * on any discovered tag.
293      */
294     public static final String EXTRA_READER_PRESENCE_CHECK_DELAY = "presence";
295 
296     /** @hide */
297     @SystemApi
298     public static final int FLAG_NDEF_PUSH_NO_CONFIRM = 0x1;
299 
300     /** @hide */
301     public static final String ACTION_HANDOVER_TRANSFER_STARTED =
302             "android.nfc.action.HANDOVER_TRANSFER_STARTED";
303 
304     /** @hide */
305     public static final String ACTION_HANDOVER_TRANSFER_DONE =
306             "android.nfc.action.HANDOVER_TRANSFER_DONE";
307 
308     /** @hide */
309     public static final String EXTRA_HANDOVER_TRANSFER_STATUS =
310             "android.nfc.extra.HANDOVER_TRANSFER_STATUS";
311 
312     /** @hide */
313     public static final int HANDOVER_TRANSFER_STATUS_SUCCESS = 0;
314     /** @hide */
315     public static final int HANDOVER_TRANSFER_STATUS_FAILURE = 1;
316 
317     /** @hide */
318     public static final String EXTRA_HANDOVER_TRANSFER_URI =
319             "android.nfc.extra.HANDOVER_TRANSFER_URI";
320 
321     // Guarded by NfcAdapter.class
322     static boolean sIsInitialized = false;
323     static boolean sHasNfcFeature;
324 
325     // Final after first constructor, except for
326     // attemptDeadServiceRecovery() when NFC crashes - we accept a best effort
327     // recovery
328     static INfcAdapter sService;
329     static INfcTag sTagService;
330     static INfcCardEmulation sCardEmulationService;
331     static INfcFCardEmulation sNfcFCardEmulationService;
332 
333     /**
334      * The NfcAdapter object for each application context.
335      * There is a 1-1 relationship between application context and
336      * NfcAdapter object.
337      */
338     static HashMap<Context, NfcAdapter> sNfcAdapters = new HashMap(); //guard by NfcAdapter.class
339 
340     /**
341      * NfcAdapter used with a null context. This ctor was deprecated but we have
342      * to support it for backwards compatibility. New methods that require context
343      * might throw when called on the null-context NfcAdapter.
344      */
345     static NfcAdapter sNullContextNfcAdapter;  // protected by NfcAdapter.class
346 
347     final NfcActivityManager mNfcActivityManager;
348     final Context mContext;
349     final HashMap<NfcUnlockHandler, INfcUnlockHandler> mNfcUnlockHandlers;
350     final Object mLock;
351 
352     ITagRemovedCallback mTagRemovedListener; // protected by mLock
353 
354     /**
355      * A callback to be invoked when the system finds a tag while the foreground activity is
356      * operating in reader mode.
357      * <p>Register your {@code ReaderCallback} implementation with {@link
358      * NfcAdapter#enableReaderMode} and disable it with {@link
359      * NfcAdapter#disableReaderMode}.
360      * @see NfcAdapter#enableReaderMode
361      */
362     public interface ReaderCallback {
onTagDiscovered(Tag tag)363         public void onTagDiscovered(Tag tag);
364     }
365 
366     /**
367      * A callback to be invoked when the system successfully delivers your {@link NdefMessage}
368      * to another device.
369      * @see #setOnNdefPushCompleteCallback
370      */
371     public interface OnNdefPushCompleteCallback {
372         /**
373          * Called on successful NDEF push.
374          *
375          * <p>This callback is usually made on a binder thread (not the UI thread).
376          *
377          * @param event {@link NfcEvent} with the {@link NfcEvent#nfcAdapter} field set
378          * @see #setNdefPushMessageCallback
379          */
onNdefPushComplete(NfcEvent event)380         public void onNdefPushComplete(NfcEvent event);
381     }
382 
383     /**
384      * A callback to be invoked when another NFC device capable of NDEF push (Android Beam)
385      * is within range.
386      * <p>Implement this interface and pass it to {@link
387      * NfcAdapter#setNdefPushMessageCallback setNdefPushMessageCallback()} in order to create an
388      * {@link NdefMessage} at the moment that another device is within range for NFC. Using this
389      * callback allows you to create a message with data that might vary based on the
390      * content currently visible to the user. Alternatively, you can call {@link
391      * #setNdefPushMessage setNdefPushMessage()} if the {@link NdefMessage} always contains the
392      * same data.
393      */
394     public interface CreateNdefMessageCallback {
395         /**
396          * Called to provide a {@link NdefMessage} to push.
397          *
398          * <p>This callback is usually made on a binder thread (not the UI thread).
399          *
400          * <p>Called when this device is in range of another device
401          * that might support NDEF push. It allows the application to
402          * create the NDEF message only when it is required.
403          *
404          * <p>NDEF push cannot occur until this method returns, so do not
405          * block for too long.
406          *
407          * <p>The Android operating system will usually show a system UI
408          * on top of your activity during this time, so do not try to request
409          * input from the user to complete the callback, or provide custom NDEF
410          * push UI. The user probably will not see it.
411          *
412          * @param event {@link NfcEvent} with the {@link NfcEvent#nfcAdapter} field set
413          * @return NDEF message to push, or null to not provide a message
414          */
createNdefMessage(NfcEvent event)415         public NdefMessage createNdefMessage(NfcEvent event);
416     }
417 
418 
419     // TODO javadoc
420     public interface CreateBeamUrisCallback {
createBeamUris(NfcEvent event)421         public Uri[] createBeamUris(NfcEvent event);
422     }
423 
424     /**
425      * A callback that is invoked when a tag is removed from the field.
426      * @see NfcAdapter#ignore
427      */
428     public interface OnTagRemovedListener {
onTagRemoved()429         void onTagRemoved();
430     }
431 
432     /**
433      * A callback to be invoked when an application has registered as a
434      * handler to unlock the device given an NFC tag at the lockscreen.
435      * @hide
436      */
437     @SystemApi
438     public interface NfcUnlockHandler {
439         /**
440          * Called at the lock screen to attempt to unlock the device with the given tag.
441          * @param tag the detected tag, to be used to unlock the device
442          * @return true if the device was successfully unlocked
443          */
onUnlockAttempted(Tag tag)444         public boolean onUnlockAttempted(Tag tag);
445     }
446 
447 
448     /**
449      * Helper to check if this device has FEATURE_NFC, but without using
450      * a context.
451      * Equivalent to
452      * context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_NFC)
453      */
hasNfcFeature()454     private static boolean hasNfcFeature() {
455         IPackageManager pm = ActivityThread.getPackageManager();
456         if (pm == null) {
457             Log.e(TAG, "Cannot get package manager, assuming no NFC feature");
458             return false;
459         }
460         try {
461             return pm.hasSystemFeature(PackageManager.FEATURE_NFC, 0);
462         } catch (RemoteException e) {
463             Log.e(TAG, "Package manager query failed, assuming no NFC feature", e);
464             return false;
465         }
466     }
467 
468     /**
469      * Helper to check if this device is NFC HCE capable, by checking for
470      * FEATURE_NFC_HOST_CARD_EMULATION and/or FEATURE_NFC_HOST_CARD_EMULATION_NFCF,
471      * but without using a context.
472      */
hasNfcHceFeature()473     private static boolean hasNfcHceFeature() {
474         IPackageManager pm = ActivityThread.getPackageManager();
475         if (pm == null) {
476             Log.e(TAG, "Cannot get package manager, assuming no NFC feature");
477             return false;
478         }
479         try {
480             return pm.hasSystemFeature(PackageManager.FEATURE_NFC_HOST_CARD_EMULATION, 0)
481                 || pm.hasSystemFeature(PackageManager.FEATURE_NFC_HOST_CARD_EMULATION_NFCF, 0);
482         } catch (RemoteException e) {
483             Log.e(TAG, "Package manager query failed, assuming no NFC feature", e);
484             return false;
485         }
486     }
487 
488     /**
489      * Returns the NfcAdapter for application context,
490      * or throws if NFC is not available.
491      * @hide
492      */
getNfcAdapter(Context context)493     public static synchronized NfcAdapter getNfcAdapter(Context context) {
494         if (!sIsInitialized) {
495             sHasNfcFeature = hasNfcFeature();
496             boolean hasHceFeature = hasNfcHceFeature();
497             /* is this device meant to have NFC */
498             if (!sHasNfcFeature && !hasHceFeature) {
499                 Log.v(TAG, "this device does not have NFC support");
500                 throw new UnsupportedOperationException();
501             }
502             sService = getServiceInterface();
503             if (sService == null) {
504                 Log.e(TAG, "could not retrieve NFC service");
505                 throw new UnsupportedOperationException();
506             }
507             if (sHasNfcFeature) {
508                 try {
509                     sTagService = sService.getNfcTagInterface();
510                 } catch (RemoteException e) {
511                     Log.e(TAG, "could not retrieve NFC Tag service");
512                     throw new UnsupportedOperationException();
513                 }
514             }
515             if (hasHceFeature) {
516                 try {
517                     sNfcFCardEmulationService = sService.getNfcFCardEmulationInterface();
518                 } catch (RemoteException e) {
519                     Log.e(TAG, "could not retrieve NFC-F card emulation service");
520                     throw new UnsupportedOperationException();
521                 }
522                 try {
523                     sCardEmulationService = sService.getNfcCardEmulationInterface();
524                 } catch (RemoteException e) {
525                     Log.e(TAG, "could not retrieve card emulation service");
526                     throw new UnsupportedOperationException();
527                 }
528             }
529 
530             sIsInitialized = true;
531         }
532         if (context == null) {
533             if (sNullContextNfcAdapter == null) {
534                 sNullContextNfcAdapter = new NfcAdapter(null);
535             }
536             return sNullContextNfcAdapter;
537         }
538         NfcAdapter adapter = sNfcAdapters.get(context);
539         if (adapter == null) {
540             adapter = new NfcAdapter(context);
541             sNfcAdapters.put(context, adapter);
542         }
543         return adapter;
544     }
545 
546     /** get handle to NFC service interface */
getServiceInterface()547     private static INfcAdapter getServiceInterface() {
548         /* get a handle to NFC service */
549         IBinder b = ServiceManager.getService("nfc");
550         if (b == null) {
551             return null;
552         }
553         return INfcAdapter.Stub.asInterface(b);
554     }
555 
556     /**
557      * Helper to get the default NFC Adapter.
558      * <p>
559      * Most Android devices will only have one NFC Adapter (NFC Controller).
560      * <p>
561      * This helper is the equivalent of:
562      * <pre>
563      * NfcManager manager = (NfcManager) context.getSystemService(Context.NFC_SERVICE);
564      * NfcAdapter adapter = manager.getDefaultAdapter();</pre>
565      * @param context the calling application's context
566      *
567      * @return the default NFC adapter, or null if no NFC adapter exists
568      */
getDefaultAdapter(Context context)569     public static NfcAdapter getDefaultAdapter(Context context) {
570         if (context == null) {
571             throw new IllegalArgumentException("context cannot be null");
572         }
573         context = context.getApplicationContext();
574         if (context == null) {
575             throw new IllegalArgumentException(
576                     "context not associated with any application (using a mock context?)");
577         }
578         /* use getSystemService() for consistency */
579         NfcManager manager = (NfcManager) context.getSystemService(Context.NFC_SERVICE);
580         if (manager == null) {
581             // NFC not available
582             return null;
583         }
584         return manager.getDefaultAdapter();
585     }
586 
587     /**
588      * Legacy NfcAdapter getter, always use {@link #getDefaultAdapter(Context)} instead.<p>
589      * This method was deprecated at API level 10 (Gingerbread MR1) because a context is required
590      * for many NFC API methods. Those methods will fail when called on an NfcAdapter
591      * object created from this method.<p>
592      * @deprecated use {@link #getDefaultAdapter(Context)}
593      * @hide
594      */
595     @Deprecated
getDefaultAdapter()596     public static NfcAdapter getDefaultAdapter() {
597         // introduced in API version 9 (GB 2.3)
598         // deprecated in API version 10 (GB 2.3.3)
599         // removed from public API in version 16 (ICS MR2)
600         // should maintain as a hidden API for binary compatibility for a little longer
601         Log.w(TAG, "WARNING: NfcAdapter.getDefaultAdapter() is deprecated, use " +
602                 "NfcAdapter.getDefaultAdapter(Context) instead", new Exception());
603 
604         return NfcAdapter.getNfcAdapter(null);
605     }
606 
NfcAdapter(Context context)607     NfcAdapter(Context context) {
608         mContext = context;
609         mNfcActivityManager = new NfcActivityManager(this);
610         mNfcUnlockHandlers = new HashMap<NfcUnlockHandler, INfcUnlockHandler>();
611         mTagRemovedListener = null;
612         mLock = new Object();
613     }
614 
615     /**
616      * @hide
617      */
getContext()618     public Context getContext() {
619         return mContext;
620     }
621 
622     /**
623      * Returns the binder interface to the service.
624      * @hide
625      */
getService()626     public INfcAdapter getService() {
627         isEnabled();  // NOP call to recover sService if it is stale
628         return sService;
629     }
630 
631     /**
632      * Returns the binder interface to the tag service.
633      * @hide
634      */
getTagService()635     public INfcTag getTagService() {
636         isEnabled();  // NOP call to recover sTagService if it is stale
637         return sTagService;
638     }
639 
640     /**
641      * Returns the binder interface to the card emulation service.
642      * @hide
643      */
getCardEmulationService()644     public INfcCardEmulation getCardEmulationService() {
645         isEnabled();
646         return sCardEmulationService;
647     }
648 
649     /**
650      * Returns the binder interface to the NFC-F card emulation service.
651      * @hide
652      */
getNfcFCardEmulationService()653     public INfcFCardEmulation getNfcFCardEmulationService() {
654         isEnabled();
655         return sNfcFCardEmulationService;
656     }
657 
658     /**
659      * Returns the binder interface to the NFC-DTA test interface.
660      * @hide
661      */
getNfcDtaInterface()662     public INfcDta getNfcDtaInterface() {
663         if (mContext == null) {
664             throw new UnsupportedOperationException("You need a context on NfcAdapter to use the "
665                     + " NFC extras APIs");
666         }
667         try {
668             return sService.getNfcDtaInterface(mContext.getPackageName());
669         } catch (RemoteException e) {
670             attemptDeadServiceRecovery(e);
671             return null;
672         }
673     }
674 
675     /**
676      * NFC service dead - attempt best effort recovery
677      * @hide
678      */
attemptDeadServiceRecovery(Exception e)679     public void attemptDeadServiceRecovery(Exception e) {
680         Log.e(TAG, "NFC service dead - attempting to recover", e);
681         INfcAdapter service = getServiceInterface();
682         if (service == null) {
683             Log.e(TAG, "could not retrieve NFC service during service recovery");
684             // nothing more can be done now, sService is still stale, we'll hit
685             // this recovery path again later
686             return;
687         }
688         // assigning to sService is not thread-safe, but this is best-effort code
689         // and on a well-behaved system should never happen
690         sService = service;
691         try {
692             sTagService = service.getNfcTagInterface();
693         } catch (RemoteException ee) {
694             Log.e(TAG, "could not retrieve NFC tag service during service recovery");
695             // nothing more can be done now, sService is still stale, we'll hit
696             // this recovery path again later
697             return;
698         }
699 
700         try {
701             sCardEmulationService = service.getNfcCardEmulationInterface();
702         } catch (RemoteException ee) {
703             Log.e(TAG, "could not retrieve NFC card emulation service during service recovery");
704         }
705 
706         try {
707             sNfcFCardEmulationService = service.getNfcFCardEmulationInterface();
708         } catch (RemoteException ee) {
709             Log.e(TAG, "could not retrieve NFC-F card emulation service during service recovery");
710         }
711 
712         return;
713     }
714 
715     /**
716      * Return true if this NFC Adapter has any features enabled.
717      *
718      * <p>If this method returns false, the NFC hardware is guaranteed not to
719      * generate or respond to any NFC communication over its NFC radio.
720      * <p>Applications can use this to check if NFC is enabled. Applications
721      * can request Settings UI allowing the user to toggle NFC using:
722      * <p><pre>startActivity(new Intent(Settings.ACTION_NFC_SETTINGS))</pre>
723      *
724      * @see android.provider.Settings#ACTION_NFC_SETTINGS
725      * @return true if this NFC Adapter has any features enabled
726      */
isEnabled()727     public boolean isEnabled() {
728         try {
729             return sService.getState() == STATE_ON;
730         } catch (RemoteException e) {
731             attemptDeadServiceRecovery(e);
732             return false;
733         }
734     }
735 
736     /**
737      * Return the state of this NFC Adapter.
738      *
739      * <p>Returns one of {@link #STATE_ON}, {@link #STATE_TURNING_ON},
740      * {@link #STATE_OFF}, {@link #STATE_TURNING_OFF}.
741      *
742      * <p>{@link #isEnabled()} is equivalent to
743      * <code>{@link #getAdapterState()} == {@link #STATE_ON}</code>
744      *
745      * @return the current state of this NFC adapter
746      *
747      * @hide
748      */
getAdapterState()749     public int getAdapterState() {
750         try {
751             return sService.getState();
752         } catch (RemoteException e) {
753             attemptDeadServiceRecovery(e);
754             return NfcAdapter.STATE_OFF;
755         }
756     }
757 
758     /**
759      * Enable NFC hardware.
760      *
761      * <p>This call is asynchronous. Listen for
762      * {@link #ACTION_ADAPTER_STATE_CHANGED} broadcasts to find out when the
763      * operation is complete.
764      *
765      * <p>If this returns true, then either NFC is already on, or
766      * a {@link #ACTION_ADAPTER_STATE_CHANGED} broadcast will be sent
767      * to indicate a state transition. If this returns false, then
768      * there is some problem that prevents an attempt to turn
769      * NFC on (for example we are in airplane mode and NFC is not
770      * toggleable in airplane mode on this platform).
771      *
772      * @hide
773      */
774     @SystemApi
775     @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
enable()776     public boolean enable() {
777         try {
778             return sService.enable();
779         } catch (RemoteException e) {
780             attemptDeadServiceRecovery(e);
781             return false;
782         }
783     }
784 
785     /**
786      * Disable NFC hardware.
787      *
788      * <p>No NFC features will work after this call, and the hardware
789      * will not perform or respond to any NFC communication.
790      *
791      * <p>This call is asynchronous. Listen for
792      * {@link #ACTION_ADAPTER_STATE_CHANGED} broadcasts to find out when the
793      * operation is complete.
794      *
795      * <p>If this returns true, then either NFC is already off, or
796      * a {@link #ACTION_ADAPTER_STATE_CHANGED} broadcast will be sent
797      * to indicate a state transition. If this returns false, then
798      * there is some problem that prevents an attempt to turn
799      * NFC off.
800      *
801      * @hide
802      */
803     @SystemApi
804     @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
disable()805     public boolean disable() {
806         try {
807             return sService.disable(true);
808         } catch (RemoteException e) {
809             attemptDeadServiceRecovery(e);
810             return false;
811         }
812     }
813 
814     /**
815      * Disable NFC hardware.
816      * @hide
817     */
818     @SystemApi
819     @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
disable(boolean persist)820     public boolean disable(boolean persist) {
821         try {
822             return sService.disable(persist);
823         } catch (RemoteException e) {
824             attemptDeadServiceRecovery(e);
825             return false;
826         }
827     }
828 
829     /**
830      * Pauses polling for a {@code timeoutInMs} millis. If polling must be resumed before timeout,
831      * use {@link #resumePolling()}.
832      * @hide
833      */
pausePolling(int timeoutInMs)834     public void pausePolling(int timeoutInMs) {
835         try {
836             sService.pausePolling(timeoutInMs);
837         } catch (RemoteException e) {
838             attemptDeadServiceRecovery(e);
839         }
840     }
841 
842     /**
843      * Resumes default polling for the current device state if polling is paused. Calling
844      * this while polling is not paused is a no-op.
845      *
846      * @hide
847      */
resumePolling()848     public void resumePolling() {
849         try {
850             sService.resumePolling();
851         } catch (RemoteException e) {
852             attemptDeadServiceRecovery(e);
853         }
854     }
855 
856     /**
857      * Set one or more {@link Uri}s to send using Android Beam (TM). Every
858      * Uri you provide must have either scheme 'file' or scheme 'content'.
859      *
860      * <p>For the data provided through this method, Android Beam tries to
861      * switch to alternate transports such as Bluetooth to achieve a fast
862      * transfer speed. Hence this method is very suitable
863      * for transferring large files such as pictures or songs.
864      *
865      * <p>The receiving side will store the content of each Uri in
866      * a file and present a notification to the user to open the file
867      * with a {@link android.content.Intent} with action
868      * {@link android.content.Intent#ACTION_VIEW}.
869      * If multiple URIs are sent, the {@link android.content.Intent} will refer
870      * to the first of the stored files.
871      *
872      * <p>This method may be called at any time before {@link Activity#onDestroy},
873      * but the URI(s) are only made available for Android Beam when the
874      * specified activity(s) are in resumed (foreground) state. The recommended
875      * approach is to call this method during your Activity's
876      * {@link Activity#onCreate} - see sample
877      * code below. This method does not immediately perform any I/O or blocking work,
878      * so is safe to call on your main thread.
879      *
880      * <p>{@link #setBeamPushUris} and {@link #setBeamPushUrisCallback}
881      * have priority over both {@link #setNdefPushMessage} and
882      * {@link #setNdefPushMessageCallback}.
883      *
884      * <p>If {@link #setBeamPushUris} is called with a null Uri array,
885      * and/or {@link #setBeamPushUrisCallback} is called with a null callback,
886      * then the Uri push will be completely disabled for the specified activity(s).
887      *
888      * <p>Code example:
889      * <pre>
890      * protected void onCreate(Bundle savedInstanceState) {
891      *     super.onCreate(savedInstanceState);
892      *     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
893      *     if (nfcAdapter == null) return;  // NFC not available on this device
894      *     nfcAdapter.setBeamPushUris(new Uri[] {uri1, uri2}, this);
895      * }</pre>
896      * And that is it. Only one call per activity is necessary. The Android
897      * OS will automatically release its references to the Uri(s) and the
898      * Activity object when it is destroyed if you follow this pattern.
899      *
900      * <p>If your Activity wants to dynamically supply Uri(s),
901      * then set a callback using {@link #setBeamPushUrisCallback} instead
902      * of using this method.
903      *
904      * <p class="note">Do not pass in an Activity that has already been through
905      * {@link Activity#onDestroy}. This is guaranteed if you call this API
906      * during {@link Activity#onCreate}.
907      *
908      * <p class="note">If this device does not support alternate transports
909      * such as Bluetooth or WiFI, calling this method does nothing.
910      *
911      * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
912      *
913      * @param uris an array of Uri(s) to push over Android Beam
914      * @param activity activity for which the Uri(s) will be pushed
915      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
916      */
setBeamPushUris(Uri[] uris, Activity activity)917     public void setBeamPushUris(Uri[] uris, Activity activity) {
918         synchronized (NfcAdapter.class) {
919             if (!sHasNfcFeature) {
920                 throw new UnsupportedOperationException();
921             }
922         }
923         if (activity == null) {
924             throw new NullPointerException("activity cannot be null");
925         }
926         if (uris != null) {
927             for (Uri uri : uris) {
928                 if (uri == null) throw new NullPointerException("Uri not " +
929                         "allowed to be null");
930                 String scheme = uri.getScheme();
931                 if (scheme == null || (!scheme.equalsIgnoreCase("file") &&
932                         !scheme.equalsIgnoreCase("content"))) {
933                     throw new IllegalArgumentException("URI needs to have " +
934                             "either scheme file or scheme content");
935                 }
936             }
937         }
938         mNfcActivityManager.setNdefPushContentUri(activity, uris);
939     }
940 
941     /**
942      * Set a callback that will dynamically generate one or more {@link Uri}s
943      * to send using Android Beam (TM). Every Uri the callback provides
944      * must have either scheme 'file' or scheme 'content'.
945      *
946      * <p>For the data provided through this callback, Android Beam tries to
947      * switch to alternate transports such as Bluetooth to achieve a fast
948      * transfer speed. Hence this method is very suitable
949      * for transferring large files such as pictures or songs.
950      *
951      * <p>The receiving side will store the content of each Uri in
952      * a file and present a notification to the user to open the file
953      * with a {@link android.content.Intent} with action
954      * {@link android.content.Intent#ACTION_VIEW}.
955      * If multiple URIs are sent, the {@link android.content.Intent} will refer
956      * to the first of the stored files.
957      *
958      * <p>This method may be called at any time before {@link Activity#onDestroy},
959      * but the URI(s) are only made available for Android Beam when the
960      * specified activity(s) are in resumed (foreground) state. The recommended
961      * approach is to call this method during your Activity's
962      * {@link Activity#onCreate} - see sample
963      * code below. This method does not immediately perform any I/O or blocking work,
964      * so is safe to call on your main thread.
965      *
966      * <p>{@link #setBeamPushUris} and {@link #setBeamPushUrisCallback}
967      * have priority over both {@link #setNdefPushMessage} and
968      * {@link #setNdefPushMessageCallback}.
969      *
970      * <p>If {@link #setBeamPushUris} is called with a null Uri array,
971      * and/or {@link #setBeamPushUrisCallback} is called with a null callback,
972      * then the Uri push will be completely disabled for the specified activity(s).
973      *
974      * <p>Code example:
975      * <pre>
976      * protected void onCreate(Bundle savedInstanceState) {
977      *     super.onCreate(savedInstanceState);
978      *     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
979      *     if (nfcAdapter == null) return;  // NFC not available on this device
980      *     nfcAdapter.setBeamPushUrisCallback(callback, this);
981      * }</pre>
982      * And that is it. Only one call per activity is necessary. The Android
983      * OS will automatically release its references to the Uri(s) and the
984      * Activity object when it is destroyed if you follow this pattern.
985      *
986      * <p class="note">Do not pass in an Activity that has already been through
987      * {@link Activity#onDestroy}. This is guaranteed if you call this API
988      * during {@link Activity#onCreate}.
989      *
990      * <p class="note">If this device does not support alternate transports
991      * such as Bluetooth or WiFI, calling this method does nothing.
992      *
993      * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
994      *
995      * @param callback callback, or null to disable
996      * @param activity activity for which the Uri(s) will be pushed
997      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
998      */
setBeamPushUrisCallback(CreateBeamUrisCallback callback, Activity activity)999     public void setBeamPushUrisCallback(CreateBeamUrisCallback callback, Activity activity) {
1000         synchronized (NfcAdapter.class) {
1001             if (!sHasNfcFeature) {
1002                 throw new UnsupportedOperationException();
1003             }
1004         }
1005         if (activity == null) {
1006             throw new NullPointerException("activity cannot be null");
1007         }
1008         mNfcActivityManager.setNdefPushContentUriCallback(activity, callback);
1009     }
1010 
1011     /**
1012      * Set a static {@link NdefMessage} to send using Android Beam (TM).
1013      *
1014      * <p>This method may be called at any time before {@link Activity#onDestroy},
1015      * but the NDEF message is only made available for NDEF push when the
1016      * specified activity(s) are in resumed (foreground) state. The recommended
1017      * approach is to call this method during your Activity's
1018      * {@link Activity#onCreate} - see sample
1019      * code below. This method does not immediately perform any I/O or blocking work,
1020      * so is safe to call on your main thread.
1021      *
1022      * <p>Only one NDEF message can be pushed by the currently resumed activity.
1023      * If both {@link #setNdefPushMessage} and
1024      * {@link #setNdefPushMessageCallback} are set, then
1025      * the callback will take priority.
1026      *
1027      * <p>If neither {@link #setNdefPushMessage} or
1028      * {@link #setNdefPushMessageCallback} have been called for your activity, then
1029      * the Android OS may choose to send a default NDEF message on your behalf,
1030      * such as a URI for your application.
1031      *
1032      * <p>If {@link #setNdefPushMessage} is called with a null NDEF message,
1033      * and/or {@link #setNdefPushMessageCallback} is called with a null callback,
1034      * then NDEF push will be completely disabled for the specified activity(s).
1035      * This also disables any default NDEF message the Android OS would have
1036      * otherwise sent on your behalf for those activity(s).
1037      *
1038      * <p>If you want to prevent the Android OS from sending default NDEF
1039      * messages completely (for all activities), you can include a
1040      * {@code <meta-data>} element inside the {@code <application>}
1041      * element of your AndroidManifest.xml file, like this:
1042      * <pre>
1043      * &lt;application ...>
1044      *     &lt;meta-data android:name="android.nfc.disable_beam_default"
1045      *         android:value="true" />
1046      * &lt;/application></pre>
1047      *
1048      * <p>The API allows for multiple activities to be specified at a time,
1049      * but it is strongly recommended to just register one at a time,
1050      * and to do so during the activity's {@link Activity#onCreate}. For example:
1051      * <pre>
1052      * protected void onCreate(Bundle savedInstanceState) {
1053      *     super.onCreate(savedInstanceState);
1054      *     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
1055      *     if (nfcAdapter == null) return;  // NFC not available on this device
1056      *     nfcAdapter.setNdefPushMessage(ndefMessage, this);
1057      * }</pre>
1058      * And that is it. Only one call per activity is necessary. The Android
1059      * OS will automatically release its references to the NDEF message and the
1060      * Activity object when it is destroyed if you follow this pattern.
1061      *
1062      * <p>If your Activity wants to dynamically generate an NDEF message,
1063      * then set a callback using {@link #setNdefPushMessageCallback} instead
1064      * of a static message.
1065      *
1066      * <p class="note">Do not pass in an Activity that has already been through
1067      * {@link Activity#onDestroy}. This is guaranteed if you call this API
1068      * during {@link Activity#onCreate}.
1069      *
1070      * <p class="note">For sending large content such as pictures and songs,
1071      * consider using {@link #setBeamPushUris}, which switches to alternate transports
1072      * such as Bluetooth to achieve a fast transfer rate.
1073      *
1074      * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
1075      *
1076      * @param message NDEF message to push over NFC, or null to disable
1077      * @param activity activity for which the NDEF message will be pushed
1078      * @param activities optional additional activities, however we strongly recommend
1079      *        to only register one at a time, and to do so in that activity's
1080      *        {@link Activity#onCreate}
1081      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
1082      */
setNdefPushMessage(NdefMessage message, Activity activity, Activity ... activities)1083     public void setNdefPushMessage(NdefMessage message, Activity activity,
1084             Activity ... activities) {
1085         synchronized (NfcAdapter.class) {
1086             if (!sHasNfcFeature) {
1087                 throw new UnsupportedOperationException();
1088             }
1089         }
1090         int targetSdkVersion = getSdkVersion();
1091         try {
1092             if (activity == null) {
1093                 throw new NullPointerException("activity cannot be null");
1094             }
1095             mNfcActivityManager.setNdefPushMessage(activity, message, 0);
1096             for (Activity a : activities) {
1097                 if (a == null) {
1098                     throw new NullPointerException("activities cannot contain null");
1099                 }
1100                 mNfcActivityManager.setNdefPushMessage(a, message, 0);
1101             }
1102         } catch (IllegalStateException e) {
1103             if (targetSdkVersion < android.os.Build.VERSION_CODES.JELLY_BEAN) {
1104                 // Less strict on old applications - just log the error
1105                 Log.e(TAG, "Cannot call API with Activity that has already " +
1106                         "been destroyed", e);
1107             } else {
1108                 // Prevent new applications from making this mistake, re-throw
1109                 throw(e);
1110             }
1111         }
1112     }
1113 
1114     /**
1115      * @hide
1116      */
1117     @SystemApi
setNdefPushMessage(NdefMessage message, Activity activity, int flags)1118     public void setNdefPushMessage(NdefMessage message, Activity activity, int flags) {
1119         synchronized (NfcAdapter.class) {
1120             if (!sHasNfcFeature) {
1121                 throw new UnsupportedOperationException();
1122             }
1123         }
1124         if (activity == null) {
1125             throw new NullPointerException("activity cannot be null");
1126         }
1127         mNfcActivityManager.setNdefPushMessage(activity, message, flags);
1128     }
1129 
1130     /**
1131      * Set a callback that dynamically generates NDEF messages to send using Android Beam (TM).
1132      *
1133      * <p>This method may be called at any time before {@link Activity#onDestroy},
1134      * but the NDEF message callback can only occur when the
1135      * specified activity(s) are in resumed (foreground) state. The recommended
1136      * approach is to call this method during your Activity's
1137      * {@link Activity#onCreate} - see sample
1138      * code below. This method does not immediately perform any I/O or blocking work,
1139      * so is safe to call on your main thread.
1140      *
1141      * <p>Only one NDEF message can be pushed by the currently resumed activity.
1142      * If both {@link #setNdefPushMessage} and
1143      * {@link #setNdefPushMessageCallback} are set, then
1144      * the callback will take priority.
1145      *
1146      * <p>If neither {@link #setNdefPushMessage} or
1147      * {@link #setNdefPushMessageCallback} have been called for your activity, then
1148      * the Android OS may choose to send a default NDEF message on your behalf,
1149      * such as a URI for your application.
1150      *
1151      * <p>If {@link #setNdefPushMessage} is called with a null NDEF message,
1152      * and/or {@link #setNdefPushMessageCallback} is called with a null callback,
1153      * then NDEF push will be completely disabled for the specified activity(s).
1154      * This also disables any default NDEF message the Android OS would have
1155      * otherwise sent on your behalf for those activity(s).
1156      *
1157      * <p>If you want to prevent the Android OS from sending default NDEF
1158      * messages completely (for all activities), you can include a
1159      * {@code <meta-data>} element inside the {@code <application>}
1160      * element of your AndroidManifest.xml file, like this:
1161      * <pre>
1162      * &lt;application ...>
1163      *     &lt;meta-data android:name="android.nfc.disable_beam_default"
1164      *         android:value="true" />
1165      * &lt;/application></pre>
1166      *
1167      * <p>The API allows for multiple activities to be specified at a time,
1168      * but it is strongly recommended to just register one at a time,
1169      * and to do so during the activity's {@link Activity#onCreate}. For example:
1170      * <pre>
1171      * protected void onCreate(Bundle savedInstanceState) {
1172      *     super.onCreate(savedInstanceState);
1173      *     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
1174      *     if (nfcAdapter == null) return;  // NFC not available on this device
1175      *     nfcAdapter.setNdefPushMessageCallback(callback, this);
1176      * }</pre>
1177      * And that is it. Only one call per activity is necessary. The Android
1178      * OS will automatically release its references to the callback and the
1179      * Activity object when it is destroyed if you follow this pattern.
1180      *
1181      * <p class="note">Do not pass in an Activity that has already been through
1182      * {@link Activity#onDestroy}. This is guaranteed if you call this API
1183      * during {@link Activity#onCreate}.
1184      * <p class="note">For sending large content such as pictures and songs,
1185      * consider using {@link #setBeamPushUris}, which switches to alternate transports
1186      * such as Bluetooth to achieve a fast transfer rate.
1187      * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
1188      *
1189      * @param callback callback, or null to disable
1190      * @param activity activity for which the NDEF message will be pushed
1191      * @param activities optional additional activities, however we strongly recommend
1192      *        to only register one at a time, and to do so in that activity's
1193      *        {@link Activity#onCreate}
1194      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
1195      */
setNdefPushMessageCallback(CreateNdefMessageCallback callback, Activity activity, Activity ... activities)1196     public void setNdefPushMessageCallback(CreateNdefMessageCallback callback, Activity activity,
1197             Activity ... activities) {
1198         synchronized (NfcAdapter.class) {
1199             if (!sHasNfcFeature) {
1200                 throw new UnsupportedOperationException();
1201             }
1202         }
1203         int targetSdkVersion = getSdkVersion();
1204         try {
1205             if (activity == null) {
1206                 throw new NullPointerException("activity cannot be null");
1207             }
1208             mNfcActivityManager.setNdefPushMessageCallback(activity, callback, 0);
1209             for (Activity a : activities) {
1210                 if (a == null) {
1211                     throw new NullPointerException("activities cannot contain null");
1212                 }
1213                 mNfcActivityManager.setNdefPushMessageCallback(a, callback, 0);
1214             }
1215         } catch (IllegalStateException e) {
1216             if (targetSdkVersion < android.os.Build.VERSION_CODES.JELLY_BEAN) {
1217                 // Less strict on old applications - just log the error
1218                 Log.e(TAG, "Cannot call API with Activity that has already " +
1219                         "been destroyed", e);
1220             } else {
1221                 // Prevent new applications from making this mistake, re-throw
1222                 throw(e);
1223             }
1224         }
1225     }
1226 
1227     /**
1228      * @hide
1229      */
setNdefPushMessageCallback(CreateNdefMessageCallback callback, Activity activity, int flags)1230     public void setNdefPushMessageCallback(CreateNdefMessageCallback callback, Activity activity,
1231             int flags) {
1232         if (activity == null) {
1233             throw new NullPointerException("activity cannot be null");
1234         }
1235         mNfcActivityManager.setNdefPushMessageCallback(activity, callback, flags);
1236     }
1237 
1238     /**
1239      * Set a callback on successful Android Beam (TM).
1240      *
1241      * <p>This method may be called at any time before {@link Activity#onDestroy},
1242      * but the callback can only occur when the
1243      * specified activity(s) are in resumed (foreground) state. The recommended
1244      * approach is to call this method during your Activity's
1245      * {@link Activity#onCreate} - see sample
1246      * code below. This method does not immediately perform any I/O or blocking work,
1247      * so is safe to call on your main thread.
1248      *
1249      * <p>The API allows for multiple activities to be specified at a time,
1250      * but it is strongly recommended to just register one at a time,
1251      * and to do so during the activity's {@link Activity#onCreate}. For example:
1252      * <pre>
1253      * protected void onCreate(Bundle savedInstanceState) {
1254      *     super.onCreate(savedInstanceState);
1255      *     NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
1256      *     if (nfcAdapter == null) return;  // NFC not available on this device
1257      *     nfcAdapter.setOnNdefPushCompleteCallback(callback, this);
1258      * }</pre>
1259      * And that is it. Only one call per activity is necessary. The Android
1260      * OS will automatically release its references to the callback and the
1261      * Activity object when it is destroyed if you follow this pattern.
1262      *
1263      * <p class="note">Do not pass in an Activity that has already been through
1264      * {@link Activity#onDestroy}. This is guaranteed if you call this API
1265      * during {@link Activity#onCreate}.
1266      *
1267      * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
1268      *
1269      * @param callback callback, or null to disable
1270      * @param activity activity for which the NDEF message will be pushed
1271      * @param activities optional additional activities, however we strongly recommend
1272      *        to only register one at a time, and to do so in that activity's
1273      *        {@link Activity#onCreate}
1274      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
1275      */
setOnNdefPushCompleteCallback(OnNdefPushCompleteCallback callback, Activity activity, Activity ... activities)1276     public void setOnNdefPushCompleteCallback(OnNdefPushCompleteCallback callback,
1277             Activity activity, Activity ... activities) {
1278         synchronized (NfcAdapter.class) {
1279             if (!sHasNfcFeature) {
1280                 throw new UnsupportedOperationException();
1281             }
1282         }
1283         int targetSdkVersion = getSdkVersion();
1284         try {
1285             if (activity == null) {
1286                 throw new NullPointerException("activity cannot be null");
1287             }
1288             mNfcActivityManager.setOnNdefPushCompleteCallback(activity, callback);
1289             for (Activity a : activities) {
1290                 if (a == null) {
1291                     throw new NullPointerException("activities cannot contain null");
1292                 }
1293                 mNfcActivityManager.setOnNdefPushCompleteCallback(a, callback);
1294             }
1295         } catch (IllegalStateException e) {
1296             if (targetSdkVersion < android.os.Build.VERSION_CODES.JELLY_BEAN) {
1297                 // Less strict on old applications - just log the error
1298                 Log.e(TAG, "Cannot call API with Activity that has already " +
1299                         "been destroyed", e);
1300             } else {
1301                 // Prevent new applications from making this mistake, re-throw
1302                 throw(e);
1303             }
1304         }
1305     }
1306 
1307     /**
1308      * Enable foreground dispatch to the given Activity.
1309      *
1310      * <p>This will give give priority to the foreground activity when
1311      * dispatching a discovered {@link Tag} to an application.
1312      *
1313      * <p>If any IntentFilters are provided to this method they are used to match dispatch Intents
1314      * for both the {@link NfcAdapter#ACTION_NDEF_DISCOVERED} and
1315      * {@link NfcAdapter#ACTION_TAG_DISCOVERED}. Since {@link NfcAdapter#ACTION_TECH_DISCOVERED}
1316      * relies on meta data outside of the IntentFilter matching for that dispatch Intent is handled
1317      * by passing in the tech lists separately. Each first level entry in the tech list represents
1318      * an array of technologies that must all be present to match. If any of the first level sets
1319      * match then the dispatch is routed through the given PendingIntent. In other words, the second
1320      * level is ANDed together and the first level entries are ORed together.
1321      *
1322      * <p>If you pass {@code null} for both the {@code filters} and {@code techLists} parameters
1323      * that acts a wild card and will cause the foreground activity to receive all tags via the
1324      * {@link NfcAdapter#ACTION_TAG_DISCOVERED} intent.
1325      *
1326      * <p>This method must be called from the main thread, and only when the activity is in the
1327      * foreground (resumed). Also, activities must call {@link #disableForegroundDispatch} before
1328      * the completion of their {@link Activity#onPause} callback to disable foreground dispatch
1329      * after it has been enabled.
1330      *
1331      * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
1332      *
1333      * @param activity the Activity to dispatch to
1334      * @param intent the PendingIntent to start for the dispatch
1335      * @param filters the IntentFilters to override dispatching for, or null to always dispatch
1336      * @param techLists the tech lists used to perform matching for dispatching of the
1337      *      {@link NfcAdapter#ACTION_TECH_DISCOVERED} intent
1338      * @throws IllegalStateException if the Activity is not currently in the foreground
1339      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
1340      */
enableForegroundDispatch(Activity activity, PendingIntent intent, IntentFilter[] filters, String[][] techLists)1341     public void enableForegroundDispatch(Activity activity, PendingIntent intent,
1342             IntentFilter[] filters, String[][] techLists) {
1343         synchronized (NfcAdapter.class) {
1344             if (!sHasNfcFeature) {
1345                 throw new UnsupportedOperationException();
1346             }
1347         }
1348         if (activity == null || intent == null) {
1349             throw new NullPointerException();
1350         }
1351         if (!activity.isResumed()) {
1352             throw new IllegalStateException("Foreground dispatch can only be enabled " +
1353                     "when your activity is resumed");
1354         }
1355         try {
1356             TechListParcel parcel = null;
1357             if (techLists != null && techLists.length > 0) {
1358                 parcel = new TechListParcel(techLists);
1359             }
1360             ActivityThread.currentActivityThread().registerOnActivityPausedListener(activity,
1361                     mForegroundDispatchListener);
1362             sService.setForegroundDispatch(intent, filters, parcel);
1363         } catch (RemoteException e) {
1364             attemptDeadServiceRecovery(e);
1365         }
1366     }
1367 
1368     /**
1369      * Disable foreground dispatch to the given activity.
1370      *
1371      * <p>After calling {@link #enableForegroundDispatch}, an activity
1372      * must call this method before its {@link Activity#onPause} callback
1373      * completes.
1374      *
1375      * <p>This method must be called from the main thread.
1376      *
1377      * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
1378      *
1379      * @param activity the Activity to disable dispatch to
1380      * @throws IllegalStateException if the Activity has already been paused
1381      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
1382      */
disableForegroundDispatch(Activity activity)1383     public void disableForegroundDispatch(Activity activity) {
1384         synchronized (NfcAdapter.class) {
1385             if (!sHasNfcFeature) {
1386                 throw new UnsupportedOperationException();
1387             }
1388         }
1389         ActivityThread.currentActivityThread().unregisterOnActivityPausedListener(activity,
1390                 mForegroundDispatchListener);
1391         disableForegroundDispatchInternal(activity, false);
1392     }
1393 
1394     OnActivityPausedListener mForegroundDispatchListener = new OnActivityPausedListener() {
1395         @Override
1396         public void onPaused(Activity activity) {
1397             disableForegroundDispatchInternal(activity, true);
1398         }
1399     };
1400 
disableForegroundDispatchInternal(Activity activity, boolean force)1401     void disableForegroundDispatchInternal(Activity activity, boolean force) {
1402         try {
1403             sService.setForegroundDispatch(null, null, null);
1404             if (!force && !activity.isResumed()) {
1405                 throw new IllegalStateException("You must disable foreground dispatching " +
1406                         "while your activity is still resumed");
1407             }
1408         } catch (RemoteException e) {
1409             attemptDeadServiceRecovery(e);
1410         }
1411     }
1412 
1413     /**
1414      * Limit the NFC controller to reader mode while this Activity is in the foreground.
1415      *
1416      * <p>In this mode the NFC controller will only act as an NFC tag reader/writer,
1417      * thus disabling any peer-to-peer (Android Beam) and card-emulation modes of
1418      * the NFC adapter on this device.
1419      *
1420      * <p>Use {@link #FLAG_READER_SKIP_NDEF_CHECK} to prevent the platform from
1421      * performing any NDEF checks in reader mode. Note that this will prevent the
1422      * {@link Ndef} tag technology from being enumerated on the tag, and that
1423      * NDEF-based tag dispatch will not be functional.
1424      *
1425      * <p>For interacting with tags that are emulated on another Android device
1426      * using Android's host-based card-emulation, the recommended flags are
1427      * {@link #FLAG_READER_NFC_A} and {@link #FLAG_READER_SKIP_NDEF_CHECK}.
1428      *
1429      * @param activity the Activity that requests the adapter to be in reader mode
1430      * @param callback the callback to be called when a tag is discovered
1431      * @param flags Flags indicating poll technologies and other optional parameters
1432      * @param extras Additional extras for configuring reader mode.
1433      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
1434      */
enableReaderMode(Activity activity, ReaderCallback callback, int flags, Bundle extras)1435     public void enableReaderMode(Activity activity, ReaderCallback callback, int flags,
1436             Bundle extras) {
1437         synchronized (NfcAdapter.class) {
1438             if (!sHasNfcFeature) {
1439                 throw new UnsupportedOperationException();
1440             }
1441         }
1442         mNfcActivityManager.enableReaderMode(activity, callback, flags, extras);
1443     }
1444 
1445     /**
1446      * Restore the NFC adapter to normal mode of operation: supporting
1447      * peer-to-peer (Android Beam), card emulation, and polling for
1448      * all supported tag technologies.
1449      *
1450      * @param activity the Activity that currently has reader mode enabled
1451      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
1452      */
disableReaderMode(Activity activity)1453     public void disableReaderMode(Activity activity) {
1454         synchronized (NfcAdapter.class) {
1455             if (!sHasNfcFeature) {
1456                 throw new UnsupportedOperationException();
1457             }
1458         }
1459         mNfcActivityManager.disableReaderMode(activity);
1460     }
1461 
1462     /**
1463      * Manually invoke Android Beam to share data.
1464      *
1465      * <p>The Android Beam animation is normally only shown when two NFC-capable
1466      * devices come into range.
1467      * By calling this method, an Activity can invoke the Beam animation directly
1468      * even if no other NFC device is in range yet. The Beam animation will then
1469      * prompt the user to tap another NFC-capable device to complete the data
1470      * transfer.
1471      *
1472      * <p>The main advantage of using this method is that it avoids the need for the
1473      * user to tap the screen to complete the transfer, as this method already
1474      * establishes the direction of the transfer and the consent of the user to
1475      * share data. Callers are responsible for making sure that the user has
1476      * consented to sharing data on NFC tap.
1477      *
1478      * <p>Note that to use this method, the passed in Activity must have already
1479      * set data to share over Beam by using method calls such as
1480      * {@link #setNdefPushMessageCallback} or
1481      * {@link #setBeamPushUrisCallback}.
1482      *
1483      * @param activity the current foreground Activity that has registered data to share
1484      * @return whether the Beam animation was successfully invoked
1485      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
1486      */
invokeBeam(Activity activity)1487     public boolean invokeBeam(Activity activity) {
1488         synchronized (NfcAdapter.class) {
1489             if (!sHasNfcFeature) {
1490                 throw new UnsupportedOperationException();
1491             }
1492         }
1493         if (activity == null) {
1494             throw new NullPointerException("activity may not be null.");
1495         }
1496         enforceResumed(activity);
1497         try {
1498             sService.invokeBeam();
1499             return true;
1500         } catch (RemoteException e) {
1501             Log.e(TAG, "invokeBeam: NFC process has died.");
1502             attemptDeadServiceRecovery(e);
1503             return false;
1504         }
1505     }
1506 
1507     /**
1508      * @hide
1509      */
invokeBeam(BeamShareData shareData)1510     public boolean invokeBeam(BeamShareData shareData) {
1511         try {
1512             Log.e(TAG, "invokeBeamInternal()");
1513             sService.invokeBeamInternal(shareData);
1514             return true;
1515         } catch (RemoteException e) {
1516             Log.e(TAG, "invokeBeam: NFC process has died.");
1517             attemptDeadServiceRecovery(e);
1518             return false;
1519         }
1520     }
1521 
1522     /**
1523      * Enable NDEF message push over NFC while this Activity is in the foreground.
1524      *
1525      * <p>You must explicitly call this method every time the activity is
1526      * resumed, and you must call {@link #disableForegroundNdefPush} before
1527      * your activity completes {@link Activity#onPause}.
1528      *
1529      * <p>Strongly recommend to use the new {@link #setNdefPushMessage}
1530      * instead: it automatically hooks into your activity life-cycle,
1531      * so you do not need to call enable/disable in your onResume/onPause.
1532      *
1533      * <p>For NDEF push to function properly the other NFC device must
1534      * support either NFC Forum's SNEP (Simple Ndef Exchange Protocol), or
1535      * Android's "com.android.npp" (Ndef Push Protocol). This was optional
1536      * on Gingerbread level Android NFC devices, but SNEP is mandatory on
1537      * Ice-Cream-Sandwich and beyond.
1538      *
1539      * <p>This method must be called from the main thread.
1540      *
1541      * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
1542      *
1543      * @param activity foreground activity
1544      * @param message a NDEF Message to push over NFC
1545      * @throws IllegalStateException if the activity is not currently in the foreground
1546      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
1547      * @deprecated use {@link #setNdefPushMessage} instead
1548      */
1549     @Deprecated
enableForegroundNdefPush(Activity activity, NdefMessage message)1550     public void enableForegroundNdefPush(Activity activity, NdefMessage message) {
1551         synchronized (NfcAdapter.class) {
1552             if (!sHasNfcFeature) {
1553                 throw new UnsupportedOperationException();
1554             }
1555         }
1556         if (activity == null || message == null) {
1557             throw new NullPointerException();
1558         }
1559         enforceResumed(activity);
1560         mNfcActivityManager.setNdefPushMessage(activity, message, 0);
1561     }
1562 
1563     /**
1564      * Disable NDEF message push over P2P.
1565      *
1566      * <p>After calling {@link #enableForegroundNdefPush}, an activity
1567      * must call this method before its {@link Activity#onPause} callback
1568      * completes.
1569      *
1570      * <p>Strongly recommend to use the new {@link #setNdefPushMessage}
1571      * instead: it automatically hooks into your activity life-cycle,
1572      * so you do not need to call enable/disable in your onResume/onPause.
1573      *
1574      * <p>This method must be called from the main thread.
1575      *
1576      * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
1577      *
1578      * @param activity the Foreground activity
1579      * @throws IllegalStateException if the Activity has already been paused
1580      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
1581      * @deprecated use {@link #setNdefPushMessage} instead
1582      */
1583     @Deprecated
disableForegroundNdefPush(Activity activity)1584     public void disableForegroundNdefPush(Activity activity) {
1585         synchronized (NfcAdapter.class) {
1586             if (!sHasNfcFeature) {
1587                 throw new UnsupportedOperationException();
1588             }
1589         }
1590         if (activity == null) {
1591             throw new NullPointerException();
1592         }
1593         enforceResumed(activity);
1594         mNfcActivityManager.setNdefPushMessage(activity, null, 0);
1595         mNfcActivityManager.setNdefPushMessageCallback(activity, null, 0);
1596         mNfcActivityManager.setOnNdefPushCompleteCallback(activity, null);
1597     }
1598 
1599     /**
1600      * Enable NDEF Push feature.
1601      * <p>This API is for the Settings application.
1602      * @hide
1603      */
1604     @SystemApi
1605     @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
enableNdefPush()1606     public boolean enableNdefPush() {
1607         if (!sHasNfcFeature) {
1608             throw new UnsupportedOperationException();
1609         }
1610         try {
1611             return sService.enableNdefPush();
1612         } catch (RemoteException e) {
1613             attemptDeadServiceRecovery(e);
1614             return false;
1615         }
1616     }
1617 
1618     /**
1619      * Disable NDEF Push feature.
1620      * <p>This API is for the Settings application.
1621      * @hide
1622      */
1623     @SystemApi
1624     @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
disableNdefPush()1625     public boolean disableNdefPush() {
1626         synchronized (NfcAdapter.class) {
1627             if (!sHasNfcFeature) {
1628                 throw new UnsupportedOperationException();
1629             }
1630         }
1631         try {
1632             return sService.disableNdefPush();
1633         } catch (RemoteException e) {
1634             attemptDeadServiceRecovery(e);
1635             return false;
1636         }
1637     }
1638 
1639     /**
1640      * Return true if the NDEF Push (Android Beam) feature is enabled.
1641      * <p>This function will return true only if both NFC is enabled, and the
1642      * NDEF Push feature is enabled.
1643      * <p>Note that if NFC is enabled but NDEF Push is disabled then this
1644      * device can still <i>receive</i> NDEF messages, it just cannot send them.
1645      * <p>Applications cannot directly toggle the NDEF Push feature, but they
1646      * can request Settings UI allowing the user to toggle NDEF Push using
1647      * <code>startActivity(new Intent(Settings.ACTION_NFCSHARING_SETTINGS))</code>
1648      * <p>Example usage in an Activity that requires NDEF Push:
1649      * <p><pre>
1650      * protected void onResume() {
1651      *     super.onResume();
1652      *     if (!nfcAdapter.isEnabled()) {
1653      *         startActivity(new Intent(Settings.ACTION_NFC_SETTINGS));
1654      *     } else if (!nfcAdapter.isNdefPushEnabled()) {
1655      *         startActivity(new Intent(Settings.ACTION_NFCSHARING_SETTINGS));
1656      *     }
1657      * }</pre>
1658      *
1659      * @see android.provider.Settings#ACTION_NFCSHARING_SETTINGS
1660      * @return true if NDEF Push feature is enabled
1661      * @throws UnsupportedOperationException if FEATURE_NFC is unavailable.
1662      */
isNdefPushEnabled()1663     public boolean isNdefPushEnabled() {
1664         synchronized (NfcAdapter.class) {
1665             if (!sHasNfcFeature) {
1666                 throw new UnsupportedOperationException();
1667             }
1668         }
1669         try {
1670             return sService.isNdefPushEnabled();
1671         } catch (RemoteException e) {
1672             attemptDeadServiceRecovery(e);
1673             return false;
1674         }
1675     }
1676 
1677     /**
1678      * Signals that you are no longer interested in communicating with an NFC tag
1679      * for as long as it remains in range.
1680      *
1681      * All future attempted communication to this tag will fail with {@link IOException}.
1682      * The NFC controller will be put in a low-power polling mode, allowing the device
1683      * to save power in cases where it's "attached" to a tag all the time (e.g. a tag in
1684      * car dock).
1685      *
1686      * Additionally the debounceMs parameter allows you to specify for how long the tag needs
1687      * to have gone out of range, before it will be dispatched again.
1688      *
1689      * Note: the NFC controller typically polls at a pretty slow interval (100 - 500 ms).
1690      * This means that if the tag repeatedly goes in and out of range (for example, in
1691      * case of a flaky connection), and the controller happens to poll every time the
1692      * tag is out of range, it *will* re-dispatch the tag after debounceMs, despite the tag
1693      * having been "in range" during the interval.
1694      *
1695      * Note 2: if a tag with another UID is detected after this API is called, its effect
1696      * will be cancelled; if this tag shows up before the amount of time specified in
1697      * debounceMs, it will be dispatched again.
1698      *
1699      * Note 3: some tags have a random UID, in which case this API won't work reliably.
1700      *
1701      * @param tag        the {@link android.nfc.Tag Tag} to ignore.
1702      * @param debounceMs minimum amount of time the tag needs to be out of range before being
1703      *                   dispatched again.
1704      * @param tagRemovedListener listener to be called when the tag is removed from the field.
1705      *                           Note that this will only be called if the tag has been out of range
1706      *                           for at least debounceMs, or if another tag came into range before
1707      *                           debounceMs. May be null in case you don't want a callback.
1708      * @param handler the {@link android.os.Handler Handler} that will be used for delivering
1709      *                the callback. if the handler is null, then the thread used for delivering
1710      *                the callback is unspecified.
1711      * @return false if the tag couldn't be found (or has already gone out of range), true otherwise
1712      */
ignore(final Tag tag, int debounceMs, final OnTagRemovedListener tagRemovedListener, final Handler handler)1713     public boolean ignore(final Tag tag, int debounceMs,
1714                           final OnTagRemovedListener tagRemovedListener, final Handler handler) {
1715         ITagRemovedCallback.Stub iListener = null;
1716         if (tagRemovedListener != null) {
1717             iListener = new ITagRemovedCallback.Stub() {
1718                 @Override
1719                 public void onTagRemoved() throws RemoteException {
1720                     if (handler != null) {
1721                         handler.post(new Runnable() {
1722                             @Override
1723                             public void run() {
1724                                 tagRemovedListener.onTagRemoved();
1725                             }
1726                         });
1727                     } else {
1728                         tagRemovedListener.onTagRemoved();
1729                     }
1730                     synchronized (mLock) {
1731                         mTagRemovedListener = null;
1732                     }
1733                 }
1734             };
1735         }
1736         synchronized (mLock) {
1737             mTagRemovedListener = iListener;
1738         }
1739         try {
1740             return sService.ignore(tag.getServiceHandle(), debounceMs, iListener);
1741         } catch (RemoteException e) {
1742             return false;
1743         }
1744     }
1745 
1746     /**
1747      * Inject a mock NFC tag.<p>
1748      * Used for testing purposes.
1749      * <p class="note">Requires the
1750      * {@link android.Manifest.permission#WRITE_SECURE_SETTINGS} permission.
1751      * @hide
1752      */
dispatch(Tag tag)1753     public void dispatch(Tag tag) {
1754         if (tag == null) {
1755             throw new NullPointerException("tag cannot be null");
1756         }
1757         try {
1758             sService.dispatch(tag);
1759         } catch (RemoteException e) {
1760             attemptDeadServiceRecovery(e);
1761         }
1762     }
1763 
1764     /**
1765      * @hide
1766      */
setP2pModes(int initiatorModes, int targetModes)1767     public void setP2pModes(int initiatorModes, int targetModes) {
1768         try {
1769             sService.setP2pModes(initiatorModes, targetModes);
1770         } catch (RemoteException e) {
1771             attemptDeadServiceRecovery(e);
1772         }
1773     }
1774 
1775     /**
1776      * Registers a new NFC unlock handler with the NFC service.
1777      *
1778      * <p />NFC unlock handlers are intended to unlock the keyguard in the presence of a trusted
1779      * NFC device. The handler should return true if it successfully authenticates the user and
1780      * unlocks the keyguard.
1781      *
1782      * <p /> The parameter {@code tagTechnologies} determines which Tag technologies will be polled for
1783      * at the lockscreen. Polling for less tag technologies reduces latency, and so it is
1784      * strongly recommended to only provide the Tag technologies that the handler is expected to
1785      * receive. There must be at least one tag technology provided, otherwise the unlock handler
1786      * is ignored.
1787      *
1788      * @hide
1789      */
1790     @SystemApi
1791     @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
addNfcUnlockHandler(final NfcUnlockHandler unlockHandler, String[] tagTechnologies)1792     public boolean addNfcUnlockHandler(final NfcUnlockHandler unlockHandler,
1793                                        String[] tagTechnologies) {
1794         synchronized (NfcAdapter.class) {
1795             if (!sHasNfcFeature) {
1796                 throw new UnsupportedOperationException();
1797             }
1798         }
1799         // If there are no tag technologies, don't bother adding unlock handler
1800         if (tagTechnologies.length == 0) {
1801             return false;
1802         }
1803 
1804         try {
1805             synchronized (mLock) {
1806                 if (mNfcUnlockHandlers.containsKey(unlockHandler)) {
1807                     // update the tag technologies
1808                     sService.removeNfcUnlockHandler(mNfcUnlockHandlers.get(unlockHandler));
1809                     mNfcUnlockHandlers.remove(unlockHandler);
1810                 }
1811 
1812                 INfcUnlockHandler.Stub iHandler = new INfcUnlockHandler.Stub() {
1813                     @Override
1814                     public boolean onUnlockAttempted(Tag tag) throws RemoteException {
1815                         return unlockHandler.onUnlockAttempted(tag);
1816                     }
1817                 };
1818 
1819                 sService.addNfcUnlockHandler(iHandler,
1820                         Tag.getTechCodesFromStrings(tagTechnologies));
1821                 mNfcUnlockHandlers.put(unlockHandler, iHandler);
1822             }
1823         } catch (RemoteException e) {
1824             attemptDeadServiceRecovery(e);
1825             return false;
1826         } catch (IllegalArgumentException e) {
1827             Log.e(TAG, "Unable to register LockscreenDispatch", e);
1828             return false;
1829         }
1830 
1831         return true;
1832     }
1833 
1834     /**
1835      * Removes a previously registered unlock handler. Also removes the tag technologies
1836      * associated with the removed unlock handler.
1837      *
1838      * @hide
1839      */
1840     @SystemApi
1841     @RequiresPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS)
removeNfcUnlockHandler(NfcUnlockHandler unlockHandler)1842     public boolean removeNfcUnlockHandler(NfcUnlockHandler unlockHandler) {
1843         synchronized (NfcAdapter.class) {
1844             if (!sHasNfcFeature) {
1845                 throw new UnsupportedOperationException();
1846             }
1847         }
1848         try {
1849             synchronized (mLock) {
1850                 if (mNfcUnlockHandlers.containsKey(unlockHandler)) {
1851                     sService.removeNfcUnlockHandler(mNfcUnlockHandlers.remove(unlockHandler));
1852                 }
1853 
1854                 return true;
1855             }
1856         } catch (RemoteException e) {
1857             attemptDeadServiceRecovery(e);
1858             return false;
1859         }
1860     }
1861 
1862     /**
1863      * @hide
1864      */
getNfcAdapterExtrasInterface()1865     public INfcAdapterExtras getNfcAdapterExtrasInterface() {
1866         if (mContext == null) {
1867             throw new UnsupportedOperationException("You need a context on NfcAdapter to use the "
1868                     + " NFC extras APIs");
1869         }
1870         try {
1871             return sService.getNfcAdapterExtrasInterface(mContext.getPackageName());
1872         } catch (RemoteException e) {
1873             attemptDeadServiceRecovery(e);
1874             return null;
1875         }
1876     }
1877 
enforceResumed(Activity activity)1878     void enforceResumed(Activity activity) {
1879         if (!activity.isResumed()) {
1880             throw new IllegalStateException("API cannot be called while activity is paused");
1881         }
1882     }
1883 
getSdkVersion()1884     int getSdkVersion() {
1885         if (mContext == null) {
1886             return android.os.Build.VERSION_CODES.GINGERBREAD; // best guess
1887         } else {
1888             return mContext.getApplicationInfo().targetSdkVersion;
1889         }
1890     }
1891 }
1892