diff options
| author | 2016-12-16 05:14:40 +0000 | |
|---|---|---|
| committer | 2016-12-16 05:14:40 +0000 | |
| commit | 9270be9a0aa70a344bb148f78643a4501b1cf76c (patch) | |
| tree | 99fbf48b08701801054de7c1b297a56c86b5565d | |
| parent | 362775ee200bc63365c2b1affac1bdffeb816ca4 (diff) | |
| parent | 1c5a117342e54996c097215ae4bc3a4b69ad3356 (diff) | |
docs: changes to broadcast documentation am: 33ec106d22 am: 377dab8ab3
am: 1c5a117342
Change-Id: I84b0410fcef3bea08c5636927864298d30989308
| -rw-r--r-- | core/java/android/content/BroadcastReceiver.java | 292 | ||||
| -rw-r--r-- | core/java/android/net/ConnectivityManager.java | 7 |
2 files changed, 74 insertions, 225 deletions
diff --git a/core/java/android/content/BroadcastReceiver.java b/core/java/android/content/BroadcastReceiver.java index 10e6fb233249..a7a86158edee 100644 --- a/core/java/android/content/BroadcastReceiver.java +++ b/core/java/android/content/BroadcastReceiver.java @@ -27,189 +27,25 @@ import android.util.Log; import android.util.Slog; /** - * Base class for code that will receive intents sent by sendBroadcast(). - * - * <p>If you don't need to send broadcasts across applications, consider using - * this class with {@link android.support.v4.content.LocalBroadcastManager} instead - * of the more general facilities described below. This will give you a much - * more efficient implementation (no cross-process communication needed) and allow - * you to avoid thinking about any security issues related to other applications - * being able to receive or send your broadcasts. + * Base class for code that receives and handles broadcast intents sent by + * {@link android.content.Context#sendBroadcast(Intent)}. * * <p>You can either dynamically register an instance of this class with * {@link Context#registerReceiver Context.registerReceiver()} - * or statically publish an implementation through the + * or statically declare an implementation with the * {@link android.R.styleable#AndroidManifestReceiver <receiver>} * tag in your <code>AndroidManifest.xml</code>. - * - * <p><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="#Security">Security</a> - * <li><a href="#ReceiverLifecycle">Receiver Lifecycle</a> - * <li><a href="#ProcessLifecycle">Process Lifecycle</a> - * </ol> * * <div class="special reference"> * <h3>Developer Guides</h3> - * <p>For information about how to use this class to receive and resolve intents, read the - * <a href="{@docRoot}guide/topics/intents/intents-filters.html">Intents and Intent Filters</a> - * developer guide.</p> - * </div> - * - * <a name="Security"></a> - * <h3>Security</h3> - * - * <p>Receivers used with the {@link Context} APIs are by their nature a - * cross-application facility, so you must consider how other applications - * may be able to abuse your use of them. Some things to consider are: - * - * <ul> - * <li><p>The Intent namespace is global. Make sure that Intent action names and - * other strings are written in a namespace you own, or else you may inadvertently - * conflict with other applications. - * <li><p>When you use {@link Context#registerReceiver(BroadcastReceiver, IntentFilter)}, - * <em>any</em> application may send broadcasts to that registered receiver. You can - * control who can send broadcasts to it through permissions described below. - * <li><p>When you publish a receiver in your application's manifest and specify - * intent-filters for it, any other application can send broadcasts to it regardless - * of the filters you specify. To prevent others from sending to it, make it - * unavailable to them with <code>android:exported="false"</code>. - * <li><p>When you use {@link Context#sendBroadcast(Intent)} or related methods, - * normally any other application can receive these broadcasts. You can control who - * can receive such broadcasts through permissions described below. Alternatively, - * starting with {@link android.os.Build.VERSION_CODES#ICE_CREAM_SANDWICH}, you - * can also safely restrict the broadcast to a single application with - * {@link Intent#setPackage(String) Intent.setPackage} - * </ul> + * <p>For more information about using BroadcastReceiver, read the + * <a href="{@docRoot}guide/components/broadcasts.html">Broadcasts</a> developer guide.</p></div> * - * <p>None of these issues exist when using - * {@link android.support.v4.content.LocalBroadcastManager}, since intents - * broadcast it never go outside of the current process. - * - * <p>Access permissions can be enforced by either the sender or receiver - * of a broadcast. - * - * <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="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="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 { private PendingResult mPendingResult; private boolean mDebugUnregister; - + /** * State for a result that is pending for a broadcast receiver. Returned * by {@link BroadcastReceiver#goAsync() goAsync()} @@ -218,7 +54,7 @@ public abstract class BroadcastReceiver { * terminate; you must call {@link #finish()} once you are done with the * broadcast. This allows you to process the broadcast off of the main * thread of your app. - * + * * <p>Note on threading: the state inside of this class is not itself * thread-safe, however you can use it from any thread if you properly * sure that you do not have races. Typically this means you will hand @@ -232,14 +68,14 @@ public abstract class BroadcastReceiver { public static final int TYPE_REGISTERED = 1; /** @hide */ public static final int TYPE_UNREGISTERED = 2; - + final int mType; final boolean mOrderedHint; final boolean mInitialStickyHint; final IBinder mToken; final int mSendingUser; final int mFlags; - + int mResultCode; String mResultData; Bundle mResultExtras; @@ -259,7 +95,7 @@ public abstract class BroadcastReceiver { mSendingUser = userId; mFlags = flags; } - + /** * Version of {@link BroadcastReceiver#setResultCode(int) * BroadcastReceiver.setResultCode(int)} for @@ -331,7 +167,7 @@ public abstract class BroadcastReceiver { mResultData = data; mResultExtras = extras; } - + /** * Version of {@link BroadcastReceiver#getAbortBroadcast() * BroadcastReceiver.getAbortBroadcast()} for @@ -350,7 +186,7 @@ public abstract class BroadcastReceiver { checkSynchronousHint(); mAbortBroadcast = true; } - + /** * Version of {@link BroadcastReceiver#clearAbortBroadcast() * BroadcastReceiver.clearAbortBroadcast()} for @@ -359,7 +195,7 @@ public abstract class BroadcastReceiver { public final void clearAbortBroadcast() { mAbortBroadcast = false; } - + /** * Finish the broadcast. The current result will be sent and the * next broadcast will proceed. @@ -397,14 +233,14 @@ public abstract class BroadcastReceiver { sendFinished(mgr); } } - + /** @hide */ public void setExtrasClassLoader(ClassLoader cl) { if (mResultExtras != null) { mResultExtras.setClassLoader(cl); } } - + /** @hide */ public void sendFinished(IActivityManager am) { synchronized (this) { @@ -412,7 +248,7 @@ public abstract class BroadcastReceiver { throw new IllegalStateException("Broadcast already finished"); } mFinished = true; - + try { if (mResultExtras != null) { mResultExtras.setAllowFds(false); @@ -448,7 +284,7 @@ public abstract class BroadcastReceiver { Log.e("BroadcastReceiver", e.getMessage(), e); } } - + public BroadcastReceiver() { } @@ -468,14 +304,15 @@ public abstract class BroadcastReceiver { * * <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}. - * + * function.</b> This means you should not perform any operations that + * return a result to you asynchronously. If you need to perform any follow up + * background work, schedule a {@link android.app.job.JobService} with + * {@link android.app.job.JobScheduler}. + * + * If you wish to interact with a service that is already running and previously + * bound using {@link android.content.Context#bindService(Intent, ServiceConnection, int) bindService()}, + * 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 @@ -483,7 +320,7 @@ public abstract class BroadcastReceiver { * 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. */ @@ -496,7 +333,7 @@ public abstract class BroadcastReceiver { * responsive to the broadcast (finishing it within 10s), but does allow * the implementation to move work related to it over to another thread * to avoid glitching the main UI thread due to disk IO. - * + * * @return Returns a {@link PendingResult} representing the result of * the active broadcast. The BroadcastRecord itself is no longer active; * all data and other interaction must go through {@link PendingResult} @@ -508,15 +345,20 @@ public abstract class BroadcastReceiver { mPendingResult = null; return res; } - + /** - * Provide a binder to an already-running service. This method is synchronous + * Provide a binder to an already-bound 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}. - * + * + * For peekService() to return a non null {@link android.os.IBinder} interface + * the service must have published it before. In other words some component + * must have called {@link android.content.Context#bindService(Intent, ServiceConnection, int)} on it. + * * @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. + * @param service Identifies the already-bound service you wish to use. See + * {@link android.content.Context#bindService(Intent, ServiceConnection, int)} + * for more information. */ public IBinder peekService(Context myContext, Intent service) { IActivityManager am = ActivityManagerNative.getDefault(); @@ -538,13 +380,13 @@ public abstract class BroadcastReceiver { * 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 class="note">This method does not work with non-ordered broadcasts such * as those sent with {@link Context#sendBroadcast(Intent) * Context.sendBroadcast}</p> - * + * * @param code The new result code. - * + * * @see #setResult(int, String, Bundle) */ public final void setResultCode(int code) { @@ -554,7 +396,7 @@ public abstract class BroadcastReceiver { /** * Retrieve the current result code, as set by the previous receiver. - * + * * @return int The current result code. */ public final int getResultCode() { @@ -567,13 +409,13 @@ public abstract class BroadcastReceiver { * {@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) { @@ -584,7 +426,7 @@ public abstract class BroadcastReceiver { /** * 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() { @@ -599,13 +441,13 @@ public abstract class BroadcastReceiver { * 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) { @@ -617,11 +459,11 @@ public abstract class BroadcastReceiver { * 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) { @@ -640,11 +482,11 @@ public abstract class BroadcastReceiver { * {@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 @@ -662,11 +504,11 @@ public abstract class BroadcastReceiver { mPendingResult.mResultData = data; mPendingResult.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() { @@ -679,10 +521,10 @@ public abstract class BroadcastReceiver { * {@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 + * 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> @@ -691,7 +533,7 @@ public abstract class BroadcastReceiver { checkSynchronousHint(); mPendingResult.mAbortBroadcast = true; } - + /** * Clears the flag indicating that this receiver should abort the current * broadcast. @@ -701,7 +543,7 @@ public abstract class BroadcastReceiver { mPendingResult.mAbortBroadcast = false; } } - + /** * Returns true if the receiver is currently processing an ordered * broadcast. @@ -709,7 +551,7 @@ public abstract class BroadcastReceiver { public final boolean isOrderedBroadcast() { return mPendingResult != null ? mPendingResult.mOrderedHint : false; } - + /** * Returns true if the receiver is currently processing the initial * value of a sticky broadcast -- that is, the value that was last @@ -719,7 +561,7 @@ public abstract class BroadcastReceiver { public final boolean isInitialStickyBroadcast() { return mPendingResult != null ? mPendingResult.mInitialStickyHint : false; } - + /** * For internal use, sets the hint about whether this BroadcastReceiver is * running in ordered mode. @@ -727,21 +569,21 @@ public abstract class BroadcastReceiver { public final void setOrderedHint(boolean isOrdered) { // Accidentally left in the SDK. } - + /** * For internal use to set the result data that is active. @hide */ public final void setPendingResult(PendingResult result) { mPendingResult = result; } - + /** * For internal use to set the result data that is active. @hide */ public final PendingResult getPendingResult() { return mPendingResult; } - + /** @hide */ public int getSendingUserId() { return mPendingResult.mSendingUser; @@ -761,19 +603,19 @@ public abstract class BroadcastReceiver { public final void setDebugUnregister(boolean debug) { mDebugUnregister = debug; } - + /** * Return the last value given to {@link #setDebugUnregister}. */ public final boolean getDebugUnregister() { return mDebugUnregister; } - + void checkSynchronousHint() { if (mPendingResult == null) { throw new IllegalStateException("Call while result is not pending"); } - + // 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. diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java index 0afb546aa4e4..f3c78171e08e 100644 --- a/core/java/android/net/ConnectivityManager.java +++ b/core/java/android/net/ConnectivityManager.java @@ -87,6 +87,13 @@ public class ConnectivityManager { * sent as an extra; it should be consulted to see what kind of * connectivity event occurred. * <p/> + * Apps targeting Android 7.0 (API level 24) and higher do not receive this + * broadcast if they declare the broadcast receiver in their manifest. Apps + * will still receive broadcasts if they register their + * {@link android.content.BroadcastReceiver} with + * {@link android.content.Context#registerReceiver Context.registerReceiver()} + * and that context is still valid. + * <p/> * If this is a connection that was the result of failing over from a * disconnected network, then the FAILOVER_CONNECTION boolean extra is * set to true. |