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      1 /*
      2  * Copyright (C) 2006 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.content;
     18 
     19 import android.app.ActivityManagerNative;
     20 import android.app.ActivityThread;
     21 import android.app.IActivityManager;
     22 import android.app.QueuedWork;
     23 import android.os.Bundle;
     24 import android.os.IBinder;
     25 import android.os.RemoteException;
     26 import android.util.Log;
     27 import android.util.Slog;
     28 
     29 /**
     30  * Base class for code that will receive intents sent by sendBroadcast().
     31  *
     32  * <p>If you don't need to send broadcasts across applications, consider using
     33  * this class with {@link android.support.v4.content.LocalBroadcastManager} instead
     34  * of the more general facilities described below.  This will give you a much
     35  * more efficient implementation (no cross-process communication needed) and allow
     36  * you to avoid thinking about any security issues related to other applications
     37  * being able to receive or send your broadcasts.
     38  *
     39  * <p>You can either dynamically register an instance of this class with
     40  * {@link Context#registerReceiver Context.registerReceiver()}
     41  * or statically publish an implementation through the
     42  * {@link android.R.styleable#AndroidManifestReceiver &lt;receiver&gt;}
     43  * tag in your <code>AndroidManifest.xml</code>.
     44  *
     45  * <p><em><strong>Note:</strong></em>
     46  * &nbsp;&nbsp;&nbsp;If registering a receiver in your
     47  * {@link android.app.Activity#onResume() Activity.onResume()}
     48  * implementation, you should unregister it in
     49  * {@link android.app.Activity#onPause() Activity.onPause()}.
     50  * (You won't receive intents when paused,
     51  * and this will cut down on unnecessary system overhead). Do not unregister in
     52  * {@link android.app.Activity#onSaveInstanceState(android.os.Bundle) Activity.onSaveInstanceState()},
     53  * because this won't be called if the user moves back in the history
     54  * stack.
     55  *
     56  * <p>There are two major classes of broadcasts that can be received:</p>
     57  * <ul>
     58  * <li> <b>Normal broadcasts</b> (sent with {@link Context#sendBroadcast(Intent)
     59  * Context.sendBroadcast}) are completely asynchronous.  All receivers of the
     60  * broadcast are run in an undefined order, often at the same time.  This is
     61  * more efficient, but means that receivers cannot use the result or abort
     62  * APIs included here.
     63  * <li> <b>Ordered broadcasts</b> (sent with {@link Context#sendOrderedBroadcast(Intent, String)
     64  * Context.sendOrderedBroadcast}) are delivered to one receiver at a time.
     65  * As each receiver executes in turn, it can propagate a result to the next
     66  * receiver, or it can completely abort the broadcast so that it won't be passed
     67  * to other receivers.  The order receivers run in can be controlled with the
     68  * {@link android.R.styleable#AndroidManifestIntentFilter_priority
     69  * android:priority} attribute of the matching intent-filter; receivers with
     70  * the same priority will be run in an arbitrary order.
     71  * </ul>
     72  *
     73  * <p>Even in the case of normal broadcasts, the system may in some
     74  * situations revert to delivering the broadcast one receiver at a time.  In
     75  * particular, for receivers that may require the creation of a process, only
     76  * one will be run at a time to avoid overloading the system with new processes.
     77  * In this situation, however, the non-ordered semantics hold: these receivers still
     78  * cannot return results or abort their broadcast.</p>
     79  *
     80  * <p>Note that, although the Intent class is used for sending and receiving
     81  * these broadcasts, the Intent broadcast mechanism here is completely separate
     82  * from Intents that are used to start Activities with
     83  * {@link Context#startActivity Context.startActivity()}.
     84  * There is no way for a BroadcastReceiver
     85  * to see or capture Intents used with startActivity(); likewise, when
     86  * you broadcast an Intent, you will never find or start an Activity.
     87  * These two operations are semantically very different: starting an
     88  * Activity with an Intent is a foreground operation that modifies what the
     89  * user is currently interacting with; broadcasting an Intent is a background
     90  * operation that the user is not normally aware of.
     91  *
     92  * <p>The BroadcastReceiver class (when launched as a component through
     93  * a manifest's {@link android.R.styleable#AndroidManifestReceiver &lt;receiver&gt;}
     94  * tag) is an important part of an
     95  * <a href="{@docRoot}guide/topics/fundamentals.html#lcycles">application's overall lifecycle</a>.</p>
     96  *
     97  * <p>Topics covered here:
     98  * <ol>
     99  * <li><a href="#Security">Security</a>
    100  * <li><a href="#ReceiverLifecycle">Receiver Lifecycle</a>
    101  * <li><a href="#ProcessLifecycle">Process Lifecycle</a>
    102  * </ol>
    103  *
    104  * <div class="special reference">
    105  * <h3>Developer Guides</h3>
    106  * <p>For information about how to use this class to receive and resolve intents, read the
    107  * <a href="{@docRoot}guide/topics/intents/intents-filters.html">Intents and Intent Filters</a>
    108  * developer guide.</p>
    109  * </div>
    110  *
    111  * <a name="Security"></a>
    112  * <h3>Security</h3>
    113  *
    114  * <p>Receivers used with the {@link Context} APIs are by their nature a
    115  * cross-application facility, so you must consider how other applications
    116  * may be able to abuse your use of them.  Some things to consider are:
    117  *
    118  * <ul>
    119  * <li><p>The Intent namespace is global.  Make sure that Intent action names and
    120  * other strings are written in a namespace you own, or else you may inadvertently
    121  * conflict with other applications.
    122  * <li><p>When you use {@link Context#registerReceiver(BroadcastReceiver, IntentFilter)},
    123  * <em>any</em> application may send broadcasts to that registered receiver.  You can
    124  * control who can send broadcasts to it through permissions described below.
    125  * <li><p>When you publish a receiver in your application's manifest and specify
    126  * intent-filters for it, any other application can send broadcasts to it regardless
    127  * of the filters you specify.  To prevent others from sending to it, make it
    128  * unavailable to them with <code>android:exported="false"</code>.
    129  * <li><p>When you use {@link Context#sendBroadcast(Intent)} or related methods,
    130  * normally any other application can receive these broadcasts.  You can control who
    131  * can receive such broadcasts through permissions described below.  Alternatively,
    132  * starting with {@link android.os.Build.VERSION_CODES#ICE_CREAM_SANDWICH}, you
    133  * can also safely restrict the broadcast to a single application with
    134  * {@link Intent#setPackage(String) Intent.setPackage}
    135  * </ul>
    136  *
    137  * <p>None of these issues exist when using
    138  * {@link android.support.v4.content.LocalBroadcastManager}, since intents
    139  * broadcast it never go outside of the current process.
    140  *
    141  * <p>Access permissions can be enforced by either the sender or receiver
    142  * of a broadcast.
    143  *
    144  * <p>To enforce a permission when sending, you supply a non-null
    145  * <var>permission</var> argument to
    146  * {@link Context#sendBroadcast(Intent, String)} or
    147  * {@link Context#sendOrderedBroadcast(Intent, String, BroadcastReceiver, android.os.Handler, int, String, Bundle)}.
    148  * Only receivers who have been granted this permission
    149  * (by requesting it with the
    150  * {@link android.R.styleable#AndroidManifestUsesPermission &lt;uses-permission&gt;}
    151  * tag in their <code>AndroidManifest.xml</code>) will be able to receive
    152  * the broadcast.
    153  *
    154  * <p>To enforce a permission when receiving, you supply a non-null
    155  * <var>permission</var> when registering your receiver -- either when calling
    156  * {@link Context#registerReceiver(BroadcastReceiver, IntentFilter, String, android.os.Handler)}
    157  * or in the static
    158  * {@link android.R.styleable#AndroidManifestReceiver &lt;receiver&gt;}
    159  * tag in your <code>AndroidManifest.xml</code>.  Only broadcasters who have
    160  * been granted this permission (by requesting it with the
    161  * {@link android.R.styleable#AndroidManifestUsesPermission &lt;uses-permission&gt;}
    162  * tag in their <code>AndroidManifest.xml</code>) will be able to send an
    163  * Intent to the receiver.
    164  *
    165  * <p>See the <a href="{@docRoot}guide/topics/security/security.html">Security and Permissions</a>
    166  * document for more information on permissions and security in general.
    167  *
    168  * <a name="ReceiverLifecycle"></a>
    169  * <h3>Receiver Lifecycle</h3>
    170  *
    171  * <p>A BroadcastReceiver object is only valid for the duration of the call
    172  * to {@link #onReceive}.  Once your code returns from this function,
    173  * the system considers the object to be finished and no longer active.
    174  *
    175  * <p>This has important repercussions to what you can do in an
    176  * {@link #onReceive} implementation: anything that requires asynchronous
    177  * operation is not available, because you will need to return from the
    178  * function to handle the asynchronous operation, but at that point the
    179  * BroadcastReceiver is no longer active and thus the system is free to kill
    180  * its process before the asynchronous operation completes.
    181  *
    182  * <p>In particular, you may <i>not</i> show a dialog or bind to a service from
    183  * within a BroadcastReceiver.  For the former, you should instead use the
    184  * {@link android.app.NotificationManager} API.  For the latter, you can
    185  * use {@link android.content.Context#startService Context.startService()} to
    186  * send a command to the service.
    187  *
    188  * <a name="ProcessLifecycle"></a>
    189  * <h3>Process Lifecycle</h3>
    190  *
    191  * <p>A process that is currently executing a BroadcastReceiver (that is,
    192  * currently running the code in its {@link #onReceive} method) is
    193  * considered to be a foreground process and will be kept running by the
    194  * system except under cases of extreme memory pressure.
    195  *
    196  * <p>Once you return from onReceive(), the BroadcastReceiver is no longer
    197  * active, and its hosting process is only as important as any other application
    198  * components that are running in it.  This is especially important because if
    199  * that process was only hosting the BroadcastReceiver (a common case for
    200  * applications that the user has never or not recently interacted with), then
    201  * upon returning from onReceive() the system will consider its process
    202  * to be empty and aggressively kill it so that resources are available for other
    203  * more important processes.
    204  *
    205  * <p>This means that for longer-running operations you will often use
    206  * a {@link android.app.Service} in conjunction with a BroadcastReceiver to keep
    207  * the containing process active for the entire time of your operation.
    208  */
    209 public abstract class BroadcastReceiver {
    210     private PendingResult mPendingResult;
    211     private boolean mDebugUnregister;
    212 
    213     /**
    214      * State for a result that is pending for a broadcast receiver.  Returned
    215      * by {@link BroadcastReceiver#goAsync() goAsync()}
    216      * while in {@link BroadcastReceiver#onReceive BroadcastReceiver.onReceive()}.
    217      * This allows you to return from onReceive() without having the broadcast
    218      * terminate; you must call {@link #finish()} once you are done with the
    219      * broadcast.  This allows you to process the broadcast off of the main
    220      * thread of your app.
    221      *
    222      * <p>Note on threading: the state inside of this class is not itself
    223      * thread-safe, however you can use it from any thread if you properly
    224      * sure that you do not have races.  Typically this means you will hand
    225      * the entire object to another thread, which will be solely responsible
    226      * for setting any results and finally calling {@link #finish()}.
    227      */
    228     public static class PendingResult {
    229         /** @hide */
    230         public static final int TYPE_COMPONENT = 0;
    231         /** @hide */
    232         public static final int TYPE_REGISTERED = 1;
    233         /** @hide */
    234         public static final int TYPE_UNREGISTERED = 2;
    235 
    236         final int mType;
    237         final boolean mOrderedHint;
    238         final boolean mInitialStickyHint;
    239         final IBinder mToken;
    240         final int mSendingUser;
    241         final int mFlags;
    242 
    243         int mResultCode;
    244         String mResultData;
    245         Bundle mResultExtras;
    246         boolean mAbortBroadcast;
    247         boolean mFinished;
    248 
    249         /** @hide */
    250         public PendingResult(int resultCode, String resultData, Bundle resultExtras, int type,
    251                 boolean ordered, boolean sticky, IBinder token, int userId, int flags) {
    252             mResultCode = resultCode;
    253             mResultData = resultData;
    254             mResultExtras = resultExtras;
    255             mType = type;
    256             mOrderedHint = ordered;
    257             mInitialStickyHint = sticky;
    258             mToken = token;
    259             mSendingUser = userId;
    260             mFlags = flags;
    261         }
    262 
    263         /**
    264          * Version of {@link BroadcastReceiver#setResultCode(int)
    265          * BroadcastReceiver.setResultCode(int)} for
    266          * asynchronous broadcast handling.
    267          */
    268         public final void setResultCode(int code) {
    269             checkSynchronousHint();
    270             mResultCode = code;
    271         }
    272 
    273         /**
    274          * Version of {@link BroadcastReceiver#getResultCode()
    275          * BroadcastReceiver.getResultCode()} for
    276          * asynchronous broadcast handling.
    277          */
    278         public final int getResultCode() {
    279             return mResultCode;
    280         }
    281 
    282         /**
    283          * Version of {@link BroadcastReceiver#setResultData(String)
    284          * BroadcastReceiver.setResultData(String)} for
    285          * asynchronous broadcast handling.
    286          */
    287         public final void setResultData(String data) {
    288             checkSynchronousHint();
    289             mResultData = data;
    290         }
    291 
    292         /**
    293          * Version of {@link BroadcastReceiver#getResultData()
    294          * BroadcastReceiver.getResultData()} for
    295          * asynchronous broadcast handling.
    296          */
    297         public final String getResultData() {
    298             return mResultData;
    299         }
    300 
    301         /**
    302          * Version of {@link BroadcastReceiver#setResultExtras(Bundle)
    303          * BroadcastReceiver.setResultExtras(Bundle)} for
    304          * asynchronous broadcast handling.
    305          */
    306         public final void setResultExtras(Bundle extras) {
    307             checkSynchronousHint();
    308             mResultExtras = extras;
    309         }
    310 
    311         /**
    312          * Version of {@link BroadcastReceiver#getResultExtras(boolean)
    313          * BroadcastReceiver.getResultExtras(boolean)} for
    314          * asynchronous broadcast handling.
    315          */
    316         public final Bundle getResultExtras(boolean makeMap) {
    317             Bundle e = mResultExtras;
    318             if (!makeMap) return e;
    319             if (e == null) mResultExtras = e = new Bundle();
    320             return e;
    321         }
    322 
    323         /**
    324          * Version of {@link BroadcastReceiver#setResult(int, String, Bundle)
    325          * BroadcastReceiver.setResult(int, String, Bundle)} for
    326          * asynchronous broadcast handling.
    327          */
    328         public final void setResult(int code, String data, Bundle extras) {
    329             checkSynchronousHint();
    330             mResultCode = code;
    331             mResultData = data;
    332             mResultExtras = extras;
    333         }
    334 
    335         /**
    336          * Version of {@link BroadcastReceiver#getAbortBroadcast()
    337          * BroadcastReceiver.getAbortBroadcast()} for
    338          * asynchronous broadcast handling.
    339          */
    340         public final boolean getAbortBroadcast() {
    341             return mAbortBroadcast;
    342         }
    343 
    344         /**
    345          * Version of {@link BroadcastReceiver#abortBroadcast()
    346          * BroadcastReceiver.abortBroadcast()} for
    347          * asynchronous broadcast handling.
    348          */
    349         public final void abortBroadcast() {
    350             checkSynchronousHint();
    351             mAbortBroadcast = true;
    352         }
    353 
    354         /**
    355          * Version of {@link BroadcastReceiver#clearAbortBroadcast()
    356          * BroadcastReceiver.clearAbortBroadcast()} for
    357          * asynchronous broadcast handling.
    358          */
    359         public final void clearAbortBroadcast() {
    360             mAbortBroadcast = false;
    361         }
    362 
    363         /**
    364          * Finish the broadcast.  The current result will be sent and the
    365          * next broadcast will proceed.
    366          */
    367         public final void finish() {
    368             if (mType == TYPE_COMPONENT) {
    369                 final IActivityManager mgr = ActivityManagerNative.getDefault();
    370                 if (QueuedWork.hasPendingWork()) {
    371                     // If this is a broadcast component, we need to make sure any
    372                     // queued work is complete before telling AM we are done, so
    373                     // we don't have our process killed before that.  We now know
    374                     // there is pending work; put another piece of work at the end
    375                     // of the list to finish the broadcast, so we don't block this
    376                     // thread (which may be the main thread) to have it finished.
    377                     //
    378                     // Note that we don't need to use QueuedWork.add() with the
    379                     // runnable, since we know the AM is waiting for us until the
    380                     // executor gets to it.
    381                     QueuedWork.singleThreadExecutor().execute( new Runnable() {
    382                         @Override public void run() {
    383                             if (ActivityThread.DEBUG_BROADCAST) Slog.i(ActivityThread.TAG,
    384                                     "Finishing broadcast after work to component " + mToken);
    385                             sendFinished(mgr);
    386                         }
    387                     });
    388                 } else {
    389                     if (ActivityThread.DEBUG_BROADCAST) Slog.i(ActivityThread.TAG,
    390                             "Finishing broadcast to component " + mToken);
    391                     sendFinished(mgr);
    392                 }
    393             } else if (mOrderedHint && mType != TYPE_UNREGISTERED) {
    394                 if (ActivityThread.DEBUG_BROADCAST) Slog.i(ActivityThread.TAG,
    395                         "Finishing broadcast to " + mToken);
    396                 final IActivityManager mgr = ActivityManagerNative.getDefault();
    397                 sendFinished(mgr);
    398             }
    399         }
    400 
    401         /** @hide */
    402         public void setExtrasClassLoader(ClassLoader cl) {
    403             if (mResultExtras != null) {
    404                 mResultExtras.setClassLoader(cl);
    405             }
    406         }
    407 
    408         /** @hide */
    409         public void sendFinished(IActivityManager am) {
    410             synchronized (this) {
    411                 if (mFinished) {
    412                     throw new IllegalStateException("Broadcast already finished");
    413                 }
    414                 mFinished = true;
    415 
    416                 try {
    417                     if (mResultExtras != null) {
    418                         mResultExtras.setAllowFds(false);
    419                     }
    420                     if (mOrderedHint) {
    421                         am.finishReceiver(mToken, mResultCode, mResultData, mResultExtras,
    422                                 mAbortBroadcast, mFlags);
    423                     } else {
    424                         // This broadcast was sent to a component; it is not ordered,
    425                         // but we still need to tell the activity manager we are done.
    426                         am.finishReceiver(mToken, 0, null, null, false, mFlags);
    427                     }
    428                 } catch (RemoteException ex) {
    429                 }
    430             }
    431         }
    432 
    433         /** @hide */
    434         public int getSendingUserId() {
    435             return mSendingUser;
    436         }
    437 
    438         void checkSynchronousHint() {
    439             // Note that we don't assert when receiving the initial sticky value,
    440             // since that may have come from an ordered broadcast.  We'll catch
    441             // them later when the real broadcast happens again.
    442             if (mOrderedHint || mInitialStickyHint) {
    443                 return;
    444             }
    445             RuntimeException e = new RuntimeException(
    446                     "BroadcastReceiver trying to return result during a non-ordered broadcast");
    447             e.fillInStackTrace();
    448             Log.e("BroadcastReceiver", e.getMessage(), e);
    449         }
    450     }
    451 
    452     public BroadcastReceiver() {
    453     }
    454 
    455     /**
    456      * This method is called when the BroadcastReceiver is receiving an Intent
    457      * broadcast.  During this time you can use the other methods on
    458      * BroadcastReceiver to view/modify the current result values.  This method
    459      * is always called within the main thread of its process, unless you
    460      * explicitly asked for it to be scheduled on a different thread using
    461      * {@link android.content.Context#registerReceiver(BroadcastReceiver,
    462      * IntentFilter, String, android.os.Handler)}. When it runs on the main
    463      * thread you should
    464      * never perform long-running operations in it (there is a timeout of
    465      * 10 seconds that the system allows before considering the receiver to
    466      * be blocked and a candidate to be killed). You cannot launch a popup dialog
    467      * in your implementation of onReceive().
    468      *
    469      * <p><b>If this BroadcastReceiver was launched through a &lt;receiver&gt; tag,
    470      * then the object is no longer alive after returning from this
    471      * function.</b>  This means you should not perform any operations that
    472      * return a result to you asynchronously -- in particular, for interacting
    473      * with services, you should use
    474      * {@link Context#startService(Intent)} instead of
    475      * {@link Context#bindService(Intent, ServiceConnection, int)}.  If you wish
    476      * to interact with a service that is already running, you can use
    477      * {@link #peekService}.
    478      *
    479      * <p>The Intent filters used in {@link android.content.Context#registerReceiver}
    480      * and in application manifests are <em>not</em> guaranteed to be exclusive. They
    481      * are hints to the operating system about how to find suitable recipients. It is
    482      * possible for senders to force delivery to specific recipients, bypassing filter
    483      * resolution.  For this reason, {@link #onReceive(Context, Intent) onReceive()}
    484      * implementations should respond only to known actions, ignoring any unexpected
    485      * Intents that they may receive.
    486      *
    487      * @param context The Context in which the receiver is running.
    488      * @param intent The Intent being received.
    489      */
    490     public abstract void onReceive(Context context, Intent intent);
    491 
    492     /**
    493      * This can be called by an application in {@link #onReceive} to allow
    494      * it to keep the broadcast active after returning from that function.
    495      * This does <em>not</em> change the expectation of being relatively
    496      * responsive to the broadcast (finishing it within 10s), but does allow
    497      * the implementation to move work related to it over to another thread
    498      * to avoid glitching the main UI thread due to disk IO.
    499      *
    500      * @return Returns a {@link PendingResult} representing the result of
    501      * the active broadcast.  The BroadcastRecord itself is no longer active;
    502      * all data and other interaction must go through {@link PendingResult}
    503      * APIs.  The {@link PendingResult#finish PendingResult.finish()} method
    504      * must be called once processing of the broadcast is done.
    505      */
    506     public final PendingResult goAsync() {
    507         PendingResult res = mPendingResult;
    508         mPendingResult = null;
    509         return res;
    510     }
    511 
    512     /**
    513      * Provide a binder to an already-running service.  This method is synchronous
    514      * and will not start the target service if it is not present, so it is safe
    515      * to call from {@link #onReceive}.
    516      *
    517      * @param myContext The Context that had been passed to {@link #onReceive(Context, Intent)}
    518      * @param service The Intent indicating the service you wish to use.  See {@link
    519      * Context#startService(Intent)} for more information.
    520      */
    521     public IBinder peekService(Context myContext, Intent service) {
    522         IActivityManager am = ActivityManagerNative.getDefault();
    523         IBinder binder = null;
    524         try {
    525             service.prepareToLeaveProcess();
    526             binder = am.peekService(service, service.resolveTypeIfNeeded(
    527                     myContext.getContentResolver()), myContext.getOpPackageName());
    528         } catch (RemoteException e) {
    529         }
    530         return binder;
    531     }
    532 
    533     /**
    534      * Change the current result code of this broadcast; only works with
    535      * broadcasts sent through
    536      * {@link Context#sendOrderedBroadcast(Intent, String)
    537      * Context.sendOrderedBroadcast}.  Often uses the
    538      * Activity {@link android.app.Activity#RESULT_CANCELED} and
    539      * {@link android.app.Activity#RESULT_OK} constants, though the
    540      * actual meaning of this value is ultimately up to the broadcaster.
    541      *
    542      * <p class="note">This method does not work with non-ordered broadcasts such
    543      * as those sent with {@link Context#sendBroadcast(Intent)
    544      * Context.sendBroadcast}</p>
    545      *
    546      * @param code The new result code.
    547      *
    548      * @see #setResult(int, String, Bundle)
    549      */
    550     public final void setResultCode(int code) {
    551         checkSynchronousHint();
    552         mPendingResult.mResultCode = code;
    553     }
    554 
    555     /**
    556      * Retrieve the current result code, as set by the previous receiver.
    557      *
    558      * @return int The current result code.
    559      */
    560     public final int getResultCode() {
    561         return mPendingResult != null ? mPendingResult.mResultCode : 0;
    562     }
    563 
    564     /**
    565      * Change the current result data of this broadcast; only works with
    566      * broadcasts sent through
    567      * {@link Context#sendOrderedBroadcast(Intent, String)
    568      * Context.sendOrderedBroadcast}.  This is an arbitrary
    569      * string whose interpretation is up to the broadcaster.
    570      *
    571      * <p><strong>This method does not work with non-ordered broadcasts such
    572      * as those sent with {@link Context#sendBroadcast(Intent)
    573      * Context.sendBroadcast}</strong></p>
    574      *
    575      * @param data The new result data; may be null.
    576      *
    577      * @see #setResult(int, String, Bundle)
    578      */
    579     public final void setResultData(String data) {
    580         checkSynchronousHint();
    581         mPendingResult.mResultData = data;
    582     }
    583 
    584     /**
    585      * Retrieve the current result data, as set by the previous receiver.
    586      * Often this is null.
    587      *
    588      * @return String The current result data; may be null.
    589      */
    590     public final String getResultData() {
    591         return mPendingResult != null ? mPendingResult.mResultData : null;
    592     }
    593 
    594     /**
    595      * Change the current result extras of this broadcast; only works with
    596      * broadcasts sent through
    597      * {@link Context#sendOrderedBroadcast(Intent, String)
    598      * Context.sendOrderedBroadcast}.  This is a Bundle
    599      * holding arbitrary data, whose interpretation is up to the
    600      * broadcaster.  Can be set to null.  Calling this method completely
    601      * replaces the current map (if any).
    602      *
    603      * <p><strong>This method does not work with non-ordered broadcasts such
    604      * as those sent with {@link Context#sendBroadcast(Intent)
    605      * Context.sendBroadcast}</strong></p>
    606      *
    607      * @param extras The new extra data map; may be null.
    608      *
    609      * @see #setResult(int, String, Bundle)
    610      */
    611     public final void setResultExtras(Bundle extras) {
    612         checkSynchronousHint();
    613         mPendingResult.mResultExtras = extras;
    614     }
    615 
    616     /**
    617      * Retrieve the current result extra data, as set by the previous receiver.
    618      * Any changes you make to the returned Map will be propagated to the next
    619      * receiver.
    620      *
    621      * @param makeMap If true then a new empty Map will be made for you if the
    622      *                current Map is null; if false you should be prepared to
    623      *                receive a null Map.
    624      *
    625      * @return Map The current extras map.
    626      */
    627     public final Bundle getResultExtras(boolean makeMap) {
    628         if (mPendingResult == null) {
    629             return null;
    630         }
    631         Bundle e = mPendingResult.mResultExtras;
    632         if (!makeMap) return e;
    633         if (e == null) mPendingResult.mResultExtras = e = new Bundle();
    634         return e;
    635     }
    636 
    637     /**
    638      * Change all of the result data returned from this broadcasts; only works
    639      * with broadcasts sent through
    640      * {@link Context#sendOrderedBroadcast(Intent, String)
    641      * Context.sendOrderedBroadcast}.  All current result data is replaced
    642      * by the value given to this method.
    643      *
    644      * <p><strong>This method does not work with non-ordered broadcasts such
    645      * as those sent with {@link Context#sendBroadcast(Intent)
    646      * Context.sendBroadcast}</strong></p>
    647      *
    648      * @param code The new result code.  Often uses the
    649      * Activity {@link android.app.Activity#RESULT_CANCELED} and
    650      * {@link android.app.Activity#RESULT_OK} constants, though the
    651      * actual meaning of this value is ultimately up to the broadcaster.
    652      * @param data The new result data.  This is an arbitrary
    653      * string whose interpretation is up to the broadcaster; may be null.
    654      * @param extras The new extra data map.  This is a Bundle
    655      * holding arbitrary data, whose interpretation is up to the
    656      * broadcaster.  Can be set to null.  This completely
    657      * replaces the current map (if any).
    658      */
    659     public final void setResult(int code, String data, Bundle extras) {
    660         checkSynchronousHint();
    661         mPendingResult.mResultCode = code;
    662         mPendingResult.mResultData = data;
    663         mPendingResult.mResultExtras = extras;
    664     }
    665 
    666     /**
    667      * Returns the flag indicating whether or not this receiver should
    668      * abort the current broadcast.
    669      *
    670      * @return True if the broadcast should be aborted.
    671      */
    672     public final boolean getAbortBroadcast() {
    673         return mPendingResult != null ? mPendingResult.mAbortBroadcast : false;
    674     }
    675 
    676     /**
    677      * Sets the flag indicating that this receiver should abort the
    678      * current broadcast; only works with broadcasts sent through
    679      * {@link Context#sendOrderedBroadcast(Intent, String)
    680      * Context.sendOrderedBroadcast}.  This will prevent
    681      * any other broadcast receivers from receiving the broadcast. It will still
    682      * call {@link #onReceive} of the BroadcastReceiver that the caller of
    683      * {@link Context#sendOrderedBroadcast(Intent, String)
    684      * Context.sendOrderedBroadcast} passed in.
    685      *
    686      * <p><strong>This method does not work with non-ordered broadcasts such
    687      * as those sent with {@link Context#sendBroadcast(Intent)
    688      * Context.sendBroadcast}</strong></p>
    689      */
    690     public final void abortBroadcast() {
    691         checkSynchronousHint();
    692         mPendingResult.mAbortBroadcast = true;
    693     }
    694 
    695     /**
    696      * Clears the flag indicating that this receiver should abort the current
    697      * broadcast.
    698      */
    699     public final void clearAbortBroadcast() {
    700         if (mPendingResult != null) {
    701             mPendingResult.mAbortBroadcast = false;
    702         }
    703     }
    704 
    705     /**
    706      * Returns true if the receiver is currently processing an ordered
    707      * broadcast.
    708      */
    709     public final boolean isOrderedBroadcast() {
    710         return mPendingResult != null ? mPendingResult.mOrderedHint : false;
    711     }
    712 
    713     /**
    714      * Returns true if the receiver is currently processing the initial
    715      * value of a sticky broadcast -- that is, the value that was last
    716      * broadcast and is currently held in the sticky cache, so this is
    717      * not directly the result of a broadcast right now.
    718      */
    719     public final boolean isInitialStickyBroadcast() {
    720         return mPendingResult != null ? mPendingResult.mInitialStickyHint : false;
    721     }
    722 
    723     /**
    724      * For internal use, sets the hint about whether this BroadcastReceiver is
    725      * running in ordered mode.
    726      */
    727     public final void setOrderedHint(boolean isOrdered) {
    728         // Accidentally left in the SDK.
    729     }
    730 
    731     /**
    732      * For internal use to set the result data that is active. @hide
    733      */
    734     public final void setPendingResult(PendingResult result) {
    735         mPendingResult = result;
    736     }
    737 
    738     /**
    739      * For internal use to set the result data that is active. @hide
    740      */
    741     public final PendingResult getPendingResult() {
    742         return mPendingResult;
    743     }
    744 
    745     /** @hide */
    746     public int getSendingUserId() {
    747         return mPendingResult.mSendingUser;
    748     }
    749 
    750     /**
    751      * Control inclusion of debugging help for mismatched
    752      * calls to {@link Context#registerReceiver(BroadcastReceiver, IntentFilter)
    753      * Context.registerReceiver()}.
    754      * If called with true, before given to registerReceiver(), then the
    755      * callstack of the following {@link Context#unregisterReceiver(BroadcastReceiver)
    756      * Context.unregisterReceiver()} call is retained, to be printed if a later
    757      * incorrect unregister call is made.  Note that doing this requires retaining
    758      * information about the BroadcastReceiver for the lifetime of the app,
    759      * resulting in a leak -- this should only be used for debugging.
    760      */
    761     public final void setDebugUnregister(boolean debug) {
    762         mDebugUnregister = debug;
    763     }
    764 
    765     /**
    766      * Return the last value given to {@link #setDebugUnregister}.
    767      */
    768     public final boolean getDebugUnregister() {
    769         return mDebugUnregister;
    770     }
    771 
    772     void checkSynchronousHint() {
    773         if (mPendingResult == null) {
    774             throw new IllegalStateException("Call while result is not pending");
    775         }
    776 
    777         // Note that we don't assert when receiving the initial sticky value,
    778         // since that may have come from an ordered broadcast.  We'll catch
    779         // them later when the real broadcast happens again.
    780         if (mPendingResult.mOrderedHint || mPendingResult.mInitialStickyHint) {
    781             return;
    782         }
    783         RuntimeException e = new RuntimeException(
    784                 "BroadcastReceiver trying to return result during a non-ordered broadcast");
    785         e.fillInStackTrace();
    786         Log.e("BroadcastReceiver", e.getMessage(), e);
    787     }
    788 }
    789 
    790