| /* |
| * Copyright (C) 2006 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.content; |
| |
| import android.app.ActivityManagerNative; |
| import android.app.IActivityManager; |
| import android.os.Bundle; |
| import android.os.IBinder; |
| import android.os.RemoteException; |
| import android.util.Log; |
| |
| /** |
| * Base class for code that will receive intents sent by sendBroadcast(). |
| * You can either dynamically register an instance of this class with |
| * {@link Context#registerReceiver Context.registerReceiver()} |
| * or statically publish an implementation through the |
| * {@link android.R.styleable#AndroidManifestReceiver <receiver>} |
| * tag in your <code>AndroidManifest.xml</code>. <em><strong>Note:</strong></em> |
| * If registering a receiver in your |
| * {@link android.app.Activity#onResume() Activity.onResume()} |
| * implementation, you should unregister it in |
| * {@link android.app.Activity#onPause() Activity.onPause()}. |
| * (You won't receive intents when paused, |
| * and this will cut down on unnecessary system overhead). Do not unregister in |
| * {@link android.app.Activity#onSaveInstanceState(android.os.Bundle) Activity.onSaveInstanceState()}, |
| * because this won't be called if the user moves back in the history |
| * stack. |
| * |
| * <p>There are two major classes of broadcasts that can be received:</p> |
| * <ul> |
| * <li> <b>Normal broadcasts</b> (sent with {@link Context#sendBroadcast(Intent) |
| * Context.sendBroadcast}) are completely asynchronous. All receivers of the |
| * broadcast are run in an undefined order, often at the same time. This is |
| * more efficient, but means that receivers cannot use the result or abort |
| * APIs included here. |
| * <li> <b>Ordered broadcasts</b> (sent with {@link Context#sendOrderedBroadcast(Intent, String) |
| * Context.sendOrderedBroadcast}) are delivered to one receiver at a time. |
| * As each receiver executes in turn, it can propagate a result to the next |
| * receiver, or it can completely abort the broadcast so that it won't be passed |
| * to other receivers. The order receivers run in can be controlled with the |
| * {@link android.R.styleable#AndroidManifestIntentFilter_priority |
| * android:priority} attribute of the matching intent-filter; receivers with |
| * the same priority will be run in an arbitrary order. |
| * </ul> |
| * |
| * <p>Even in the case of normal broadcasts, the system may in some |
| * situations revert to delivering the broadcast one receiver at a time. In |
| * particular, for receivers that may require the creation of a process, only |
| * one will be run at a time to avoid overloading the system with new processes. |
| * In this situation, however, the non-ordered semantics hold: these receivers still |
| * cannot return results or abort their broadcast.</p> |
| * |
| * <p>Note that, although the Intent class is used for sending and receiving |
| * these broadcasts, the Intent broadcast mechanism here is completely separate |
| * from Intents that are used to start Activities with |
| * {@link Context#startActivity Context.startActivity()}. |
| * There is no way for a BroadcastReceiver |
| * to see or capture Intents used with startActivity(); likewise, when |
| * you broadcast an Intent, you will never find or start an Activity. |
| * These two operations are semantically very different: starting an |
| * Activity with an Intent is a foreground operation that modifies what the |
| * user is currently interacting with; broadcasting an Intent is a background |
| * operation that the user is not normally aware of. |
| * |
| * <p>The BroadcastReceiver class (when launched as a component through |
| * a manifest's {@link android.R.styleable#AndroidManifestReceiver <receiver>} |
| * tag) is an important part of an |
| * <a href="{@docRoot}guide/topics/fundamentals.html#lcycles">application's overall lifecycle</a>.</p> |
| * |
| * <p>Topics covered here: |
| * <ol> |
| * <li><a href="#ReceiverLifecycle">Receiver Lifecycle</a> |
| * <li><a href="#Permissions">Permissions</a> |
| * <li><a href="#ProcessLifecycle">Process Lifecycle</a> |
| * </ol> |
| * |
| * <a name="ReceiverLifecycle"></a> |
| * <h3>Receiver Lifecycle</h3> |
| * |
| * <p>A BroadcastReceiver object is only valid for the duration of the call |
| * to {@link #onReceive}. Once your code returns from this function, |
| * the system considers the object to be finished and no longer active. |
| * |
| * <p>This has important repercussions to what you can do in an |
| * {@link #onReceive} implementation: anything that requires asynchronous |
| * operation is not available, because you will need to return from the |
| * function to handle the asynchronous operation, but at that point the |
| * BroadcastReceiver is no longer active and thus the system is free to kill |
| * its process before the asynchronous operation completes. |
| * |
| * <p>In particular, you may <i>not</i> show a dialog or bind to a service from |
| * within a BroadcastReceiver. For the former, you should instead use the |
| * {@link android.app.NotificationManager} API. For the latter, you can |
| * use {@link android.content.Context#startService Context.startService()} to |
| * send a command to the service. |
| * |
| * <a name="Permissions"></a> |
| * <h3>Permissions</h3> |
| * |
| * <p>Access permissions can be enforced by either the sender or receiver |
| * of an Intent. |
| * |
| * <p>To enforce a permission when sending, you supply a non-null |
| * <var>permission</var> argument to |
| * {@link Context#sendBroadcast(Intent, String)} or |
| * {@link Context#sendOrderedBroadcast(Intent, String, BroadcastReceiver, android.os.Handler, int, String, Bundle)}. |
| * Only receivers who have been granted this permission |
| * (by requesting it with the |
| * {@link android.R.styleable#AndroidManifestUsesPermission <uses-permission>} |
| * tag in their <code>AndroidManifest.xml</code>) will be able to receive |
| * the broadcast. |
| * |
| * <p>To enforce a permission when receiving, you supply a non-null |
| * <var>permission</var> when registering your receiver -- either when calling |
| * {@link Context#registerReceiver(BroadcastReceiver, IntentFilter, String, android.os.Handler)} |
| * or in the static |
| * {@link android.R.styleable#AndroidManifestReceiver <receiver>} |
| * tag in your <code>AndroidManifest.xml</code>. Only broadcasters who have |
| * been granted this permission (by requesting it with the |
| * {@link android.R.styleable#AndroidManifestUsesPermission <uses-permission>} |
| * tag in their <code>AndroidManifest.xml</code>) will be able to send an |
| * Intent to the receiver. |
| * |
| * <p>See the <a href="{@docRoot}guide/topics/security/security.html">Security and Permissions</a> |
| * document for more information on permissions and security in general. |
| * |
| * <a name="ProcessLifecycle"></a> |
| * <h3>Process Lifecycle</h3> |
| * |
| * <p>A process that is currently executing a BroadcastReceiver (that is, |
| * currently running the code in its {@link #onReceive} method) is |
| * considered to be a foreground process and will be kept running by the |
| * system except under cases of extreme memory pressure. |
| * |
| * <p>Once you return from onReceive(), the BroadcastReceiver is no longer |
| * active, and its hosting process is only as important as any other application |
| * components that are running in it. This is especially important because if |
| * that process was only hosting the BroadcastReceiver (a common case for |
| * applications that the user has never or not recently interacted with), then |
| * upon returning from onReceive() the system will consider its process |
| * to be empty and aggressively kill it so that resources are available for other |
| * more important processes. |
| * |
| * <p>This means that for longer-running operations you will often use |
| * a {@link android.app.Service} in conjunction with a BroadcastReceiver to keep |
| * the containing process active for the entire time of your operation. |
| */ |
| public abstract class BroadcastReceiver { |
| public BroadcastReceiver() { |
| } |
| |
| /** |
| * This method is called when the BroadcastReceiver is receiving an Intent |
| * broadcast. During this time you can use the other methods on |
| * BroadcastReceiver to view/modify the current result values. The function |
| * is normally called within the main thread of its process, so you should |
| * never perform long-running operations in it (there is a timeout of |
| * 10 seconds that the system allows before considering the receiver to |
| * be blocked and a candidate to be killed). You cannot launch a popup dialog |
| * in your implementation of onReceive(). |
| * |
| * <p><b>If this BroadcastReceiver was launched through a <receiver> tag, |
| * then the object is no longer alive after returning from this |
| * function.</b> This means you should not perform any operations that |
| * return a result to you asynchronously -- in particular, for interacting |
| * with services, you should use |
| * {@link Context#startService(Intent)} instead of |
| * {@link Context#bindService(Intent, ServiceConnection, int)}. If you wish |
| * to interact with a service that is already running, you can use |
| * {@link #peekService}. |
| * |
| * <p>The Intent filters used in {@link android.content.Context#registerReceiver} |
| * and in application manifests are <em>not</em> guaranteed to be exclusive. They |
| * are hints to the operating system about how to find suitable recipients. It is |
| * possible for senders to force delivery to specific recipients, bypassing filter |
| * resolution. For this reason, {@link #onReceive(Context, Intent) onReceive()} |
| * implementations should respond only to known actions, ignoring any unexpected |
| * Intents that they may receive. |
| * |
| * @param context The Context in which the receiver is running. |
| * @param intent The Intent being received. |
| */ |
| public abstract void onReceive(Context context, Intent intent); |
| |
| /** |
| * Provide a binder to an already-running service. This method is synchronous |
| * and will not start the target service if it is not present, so it is safe |
| * to call from {@link #onReceive}. |
| * |
| * @param myContext The Context that had been passed to {@link #onReceive(Context, Intent)} |
| * @param service The Intent indicating the service you wish to use. See {@link |
| * Context#startService(Intent)} for more information. |
| */ |
| public IBinder peekService(Context myContext, Intent service) { |
| IActivityManager am = ActivityManagerNative.getDefault(); |
| IBinder binder = null; |
| try { |
| binder = am.peekService(service, service.resolveTypeIfNeeded( |
| myContext.getContentResolver())); |
| } catch (RemoteException e) { |
| } |
| return binder; |
| } |
| |
| /** |
| * Change the current result code of this broadcast; only works with |
| * broadcasts sent through |
| * {@link Context#sendOrderedBroadcast(Intent, String) |
| * Context.sendOrderedBroadcast}. Often uses the |
| * Activity {@link android.app.Activity#RESULT_CANCELED} and |
| * {@link android.app.Activity#RESULT_OK} constants, though the |
| * actual meaning of this value is ultimately up to the broadcaster. |
| * |
| * <p><strong>This method does not work with non-ordered broadcasts such |
| * as those sent with {@link Context#sendBroadcast(Intent) |
| * Context.sendBroadcast}</strong></p> |
| * |
| * @param code The new result code. |
| * |
| * @see #setResult(int, String, Bundle) |
| */ |
| public final void setResultCode(int code) { |
| checkSynchronousHint(); |
| mResultCode = code; |
| } |
| |
| /** |
| * Retrieve the current result code, as set by the previous receiver. |
| * |
| * @return int The current result code. |
| */ |
| public final int getResultCode() { |
| return mResultCode; |
| } |
| |
| /** |
| * Change the current result data of this broadcast; only works with |
| * broadcasts sent through |
| * {@link Context#sendOrderedBroadcast(Intent, String) |
| * Context.sendOrderedBroadcast}. This is an arbitrary |
| * string whose interpretation is up to the broadcaster. |
| * |
| * <p><strong>This method does not work with non-ordered broadcasts such |
| * as those sent with {@link Context#sendBroadcast(Intent) |
| * Context.sendBroadcast}</strong></p> |
| * |
| * @param data The new result data; may be null. |
| * |
| * @see #setResult(int, String, Bundle) |
| */ |
| public final void setResultData(String data) { |
| checkSynchronousHint(); |
| mResultData = data; |
| } |
| |
| /** |
| * Retrieve the current result data, as set by the previous receiver. |
| * Often this is null. |
| * |
| * @return String The current result data; may be null. |
| */ |
| public final String getResultData() { |
| return mResultData; |
| } |
| |
| /** |
| * Change the current result extras of this broadcast; only works with |
| * broadcasts sent through |
| * {@link Context#sendOrderedBroadcast(Intent, String) |
| * Context.sendOrderedBroadcast}. This is a Bundle |
| * holding arbitrary data, whose interpretation is up to the |
| * broadcaster. Can be set to null. Calling this method completely |
| * replaces the current map (if any). |
| * |
| * <p><strong>This method does not work with non-ordered broadcasts such |
| * as those sent with {@link Context#sendBroadcast(Intent) |
| * Context.sendBroadcast}</strong></p> |
| * |
| * @param extras The new extra data map; may be null. |
| * |
| * @see #setResult(int, String, Bundle) |
| */ |
| public final void setResultExtras(Bundle extras) { |
| checkSynchronousHint(); |
| mResultExtras = extras; |
| } |
| |
| /** |
| * Retrieve the current result extra data, as set by the previous receiver. |
| * Any changes you make to the returned Map will be propagated to the next |
| * receiver. |
| * |
| * @param makeMap If true then a new empty Map will be made for you if the |
| * current Map is null; if false you should be prepared to |
| * receive a null Map. |
| * |
| * @return Map The current extras map. |
| */ |
| public final Bundle getResultExtras(boolean makeMap) { |
| Bundle e = mResultExtras; |
| if (!makeMap) return e; |
| if (e == null) mResultExtras = e = new Bundle(); |
| return e; |
| } |
| |
| /** |
| * Change all of the result data returned from this broadcasts; only works |
| * with broadcasts sent through |
| * {@link Context#sendOrderedBroadcast(Intent, String) |
| * Context.sendOrderedBroadcast}. All current result data is replaced |
| * by the value given to this method. |
| * |
| * <p><strong>This method does not work with non-ordered broadcasts such |
| * as those sent with {@link Context#sendBroadcast(Intent) |
| * Context.sendBroadcast}</strong></p> |
| * |
| * @param code The new result code. Often uses the |
| * Activity {@link android.app.Activity#RESULT_CANCELED} and |
| * {@link android.app.Activity#RESULT_OK} constants, though the |
| * actual meaning of this value is ultimately up to the broadcaster. |
| * @param data The new result data. This is an arbitrary |
| * string whose interpretation is up to the broadcaster; may be null. |
| * @param extras The new extra data map. This is a Bundle |
| * holding arbitrary data, whose interpretation is up to the |
| * broadcaster. Can be set to null. This completely |
| * replaces the current map (if any). |
| */ |
| public final void setResult(int code, String data, Bundle extras) { |
| checkSynchronousHint(); |
| mResultCode = code; |
| mResultData = data; |
| mResultExtras = extras; |
| } |
| |
| /** |
| * Returns the flag indicating whether or not this receiver should |
| * abort the current broadcast. |
| * |
| * @return True if the broadcast should be aborted. |
| */ |
| public final boolean getAbortBroadcast() { |
| return mAbortBroadcast; |
| } |
| |
| /** |
| * Sets the flag indicating that this receiver should abort the |
| * current broadcast; only works with broadcasts sent through |
| * {@link Context#sendOrderedBroadcast(Intent, String) |
| * Context.sendOrderedBroadcast}. This will prevent |
| * any other broadcast receivers from receiving the broadcast. It will still |
| * call {@link #onReceive} of the BroadcastReceiver that the caller of |
| * {@link Context#sendOrderedBroadcast(Intent, String) |
| * Context.sendOrderedBroadcast} passed in. |
| * |
| * <p><strong>This method does not work with non-ordered broadcasts such |
| * as those sent with {@link Context#sendBroadcast(Intent) |
| * Context.sendBroadcast}</strong></p> |
| */ |
| public final void abortBroadcast() { |
| checkSynchronousHint(); |
| mAbortBroadcast = true; |
| } |
| |
| /** |
| * Clears the flag indicating that this receiver should abort the current |
| * broadcast. |
| */ |
| public final void clearAbortBroadcast() { |
| mAbortBroadcast = false; |
| } |
| |
| /** |
| * Returns true if the receiver is currently processing an ordered |
| * broadcast. |
| */ |
| public final boolean isOrderedBroadcast() { |
| return mOrderedHint; |
| } |
| |
| /** |
| * Returns true if the receiver is currently processing the initial |
| * value of a sticky broadcast -- that is, the value that was last |
| * broadcast and is currently held in the sticky cache, so this is |
| * not directly the result of a broadcast right now. |
| */ |
| public final boolean isInitialStickyBroadcast() { |
| return mInitialStickyHint; |
| } |
| |
| /** |
| * For internal use, sets the hint about whether this BroadcastReceiver is |
| * running in ordered mode. |
| */ |
| public final void setOrderedHint(boolean isOrdered) { |
| mOrderedHint = isOrdered; |
| } |
| |
| /** |
| * For internal use, sets the hint about whether this BroadcastReceiver is |
| * receiving the initial sticky broadcast value. @hide |
| */ |
| public final void setInitialStickyHint(boolean isInitialSticky) { |
| mInitialStickyHint = isInitialSticky; |
| } |
| |
| /** |
| * Control inclusion of debugging help for mismatched |
| * calls to {@ Context#registerReceiver(BroadcastReceiver, IntentFilter) |
| * Context.registerReceiver()}. |
| * If called with true, before given to registerReceiver(), then the |
| * callstack of the following {@link Context#unregisterReceiver(BroadcastReceiver) |
| * Context.unregisterReceiver()} call is retained, to be printed if a later |
| * incorrect unregister call is made. Note that doing this requires retaining |
| * information about the BroadcastReceiver for the lifetime of the app, |
| * resulting in a leak -- this should only be used for debugging. |
| */ |
| public final void setDebugUnregister(boolean debug) { |
| mDebugUnregister = debug; |
| } |
| |
| /** |
| * Return the last value given to {@link #setDebugUnregister}. |
| */ |
| public final boolean getDebugUnregister() { |
| return mDebugUnregister; |
| } |
| |
| void checkSynchronousHint() { |
| // Note that we don't assert when receiving the initial sticky value, |
| // since that may have come from an ordered broadcast. We'll catch |
| // them later when the real broadcast happens again. |
| if (mOrderedHint || mInitialStickyHint) { |
| return; |
| } |
| RuntimeException e = new RuntimeException( |
| "BroadcastReceiver trying to return result during a non-ordered broadcast"); |
| e.fillInStackTrace(); |
| Log.e("BroadcastReceiver", e.getMessage(), e); |
| } |
| |
| private int mResultCode; |
| private String mResultData; |
| private Bundle mResultExtras; |
| private boolean mAbortBroadcast; |
| private boolean mDebugUnregister; |
| private boolean mOrderedHint; |
| private boolean mInitialStickyHint; |
| } |
| |