广播接受者
注册
ContextImpl
@Override public Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter) { return registerReceiver(receiver, filter, null, null); }
@Override public Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter) { return registerReceiver(receiver, filter, null, null); }
@Override public Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter, String broadcastPermission, Handler scheduler) { return registerReceiverInternal(receiver, getUserId(), filter, broadcastPermission, scheduler, getOuterContext()); }
@Override public Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter, String broadcastPermission, Handler scheduler) { if (receiver == null) { // Allow retrieving current sticky broadcast; this is safe since we // aren't actually registering a receiver. return super.registerReceiver(null, filter, broadcastPermission, scheduler); } else { throw new ReceiverCallNotAllowedException( "BroadcastReceiver components are not allowed to register to receive intents"); } }
最终都执行
private Intent registerReceiverInternal(BroadcastReceiver receiver, int userId, IntentFilter filter, String broadcastPermission, Handler scheduler, Context context) { IIntentReceiver rd = null; if (receiver != null) { if (mPackageInfo != null && context != null) { if (scheduler == null) { scheduler = mMainThread.getHandler(); } rd = mPackageInfo.getReceiverDispatcher( receiver, context, scheduler, mMainThread.getInstrumentation(), true); } else { if (scheduler == null) { scheduler = mMainThread.getHandler(); } rd = new LoadedApk.ReceiverDispatcher( receiver, context, scheduler, null, true).getIIntentReceiver(); } } try { return ActivityManagerNative.getDefault().registerReceiver( mMainThread.getApplicationThread(), mBasePackageName, rd, filter, broadcastPermission, userId); } catch (RemoteException e) { return null; } }
AMS
public Intent registerReceiver(IApplicationThread caller, String callerPackage, IIntentReceiver receiver, IntentFilter filter, String permission, int userId) { enforceNotIsolatedCaller("registerReceiver"); ArrayList<Intent> stickyIntents = null; ProcessRecord callerApp = null; int callingUid; int callingPid; synchronized(this) { if (caller != null) { callerApp = getRecordForAppLocked(caller); if (callerApp == null) { throw new SecurityException( "Unable to find app for caller " + caller + " (pid=" + Binder.getCallingPid() + ") when registering receiver " + receiver); } if (callerApp.info.uid != Process.SYSTEM_UID && !callerApp.pkgList.containsKey(callerPackage) && !"android".equals(callerPackage)) { throw new SecurityException("Given caller package " + callerPackage + " is not running in process " + callerApp); } callingUid = callerApp.info.uid; callingPid = callerApp.pid; } else { callerPackage = null; callingUid = Binder.getCallingUid(); callingPid = Binder.getCallingPid(); } userId = handleIncomingUser(callingPid, callingUid, userId, true, ALLOW_FULL_ONLY, "registerReceiver", callerPackage); Iterator<String> actions = filter.actionsIterator(); if (actions == null) { ArrayList<String> noAction = new ArrayList<String>(1); noAction.add(null); actions = noAction.iterator(); } // Collect stickies of users int[] userIds = { UserHandle.USER_ALL, UserHandle.getUserId(callingUid) }; while (actions.hasNext()) { String action = actions.next(); for (int id : userIds) { ArrayMap<String, ArrayList<Intent>> stickies = mStickyBroadcasts.get(id); if (stickies != null) { ArrayList<Intent> intents = stickies.get(action); if (intents != null) { if (stickyIntents == null) { stickyIntents = new ArrayList<Intent>(); } stickyIntents.addAll(intents); } } } } } ArrayList<Intent> allSticky = null; if (stickyIntents != null) { final ContentResolver resolver = mContext.getContentResolver(); // Look for any matching sticky broadcasts... for (int i = 0, N = stickyIntents.size(); i < N; i++) { Intent intent = stickyIntents.get(i); // If intent has scheme "content", it will need to acccess // provider that needs to lock mProviderMap in ActivityThread // and also it may need to wait application response, so we // cannot lock ActivityManagerService here. if (filter.match(resolver, intent, true, TAG) >= 0) { if (allSticky == null) { allSticky = new ArrayList<Intent>(); } allSticky.add(intent); } } } // The first sticky in the list is returned directly back to the client. Intent sticky = allSticky != null ? allSticky.get(0) : null; if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Register receiver " + filter + ": " + sticky); if (receiver == null) { return sticky; } synchronized (this) { if (callerApp != null && (callerApp.thread == null || callerApp.thread.asBinder() != caller.asBinder())) { // Original caller already died return null; } ReceiverList rl = mRegisteredReceivers.get(receiver.asBinder()); if (rl == null) { rl = new ReceiverList(this, callerApp, callingPid, callingUid, userId, receiver); if (rl.app != null) { rl.app.receivers.add(rl); } else { try { receiver.asBinder().linkToDeath(rl, 0); } catch (RemoteException e) { return sticky; } rl.linkedToDeath = true; } mRegisteredReceivers.put(receiver.asBinder(), rl); } else if (rl.uid != callingUid) { throw new IllegalArgumentException( "Receiver requested to register for uid " + callingUid + " was previously registered for uid " + rl.uid); } else if (rl.pid != callingPid) { throw new IllegalArgumentException( "Receiver requested to register for pid " + callingPid + " was previously registered for pid " + rl.pid); } else if (rl.userId != userId) { throw new IllegalArgumentException( "Receiver requested to register for user " + userId + " was previously registered for user " + rl.userId); } BroadcastFilter bf = new BroadcastFilter(filter, rl, callerPackage, permission, callingUid, userId); rl.add(bf); if (!bf.debugCheck()) { Slog.w(TAG, "==> For Dynamic broadcast"); } mReceiverResolver.addFilter(bf); // Enqueue broadcasts for all existing stickies that match // this filter. if (allSticky != null) { ArrayList receivers = new ArrayList(); receivers.add(bf); final int stickyCount = allSticky.size(); for (int i = 0; i < stickyCount; i++) { Intent intent = allSticky.get(i); BroadcastQueue queue = broadcastQueueForIntent(intent); BroadcastRecord r = new BroadcastRecord(queue, intent, null, null, -1, -1, null, null, AppOpsManager.OP_NONE, null, receivers, null, 0, null, null, false, true, true, -1); queue.enqueueParallelBroadcastLocked(r); queue.scheduleBroadcastsLocked(); } } return sticky; } }
1.在AMS中，BroadcastReceiver的过滤条件由BroadcastFilter表示，该类从IntentFilter派生。由于BroadcastReceiver可设置多个过滤条件（即多次为同一个BroadcastReceiver对象调用registerReceiver函数以设置不同的过滤条件），故AMS使用ReceiverList（从ArrayList<BroadcastFilter>派生）这种数据类型来表达这种一对多的关系
2.RecevierList除了能存储多个BroadcastFilter外，还应该有成员指向某一个具体BroadcastReceiver。如果不这样，那么又是如何知道到底是哪个BroadcastReceiver设置的过滤条件呢?前面说过，BroadcastReceiver接收广播是通过IIntentReceiver接口进行的，故ReceiverList中有receiver成员变量指向IIntentReceiver。
3.AMS提供mRegisterReceiver用于保存IIntentReceiver和对应ReceiverList的关系。此外，AMS还提供mReceiverResolver变量用于存储所有动态注册的BroadcastReceiver所设置的过滤条件
@Override public void sendBroadcast(Intent intent) { warnIfCallingFromSystemProcess(); String resolvedType = intent.resolveTypeIfNeeded(getContentResolver()); try { intent.prepareToLeaveProcess(); ActivityManagerNative.getDefault().broadcastIntent( mMainThread.getApplicationThread(), intent, resolvedType, null, Activity.RESULT_OK, null, null, null, AppOpsManager.OP_NONE, null, false, false, getUserId()); } catch (RemoteException e) { throw new RuntimeException("Failure from system", e); } }
broadcastIntent由AMS的broadcastIntentLocked完成
private final int broadcastIntentLocked(ProcessRecord callerApp, String callerPackage, Intent intent, String resolvedType, IIntentReceiver resultTo, int resultCode, String resultData, Bundle resultExtras, String[] requiredPermissions, int appOp, Bundle options, boolean ordered, boolean sticky, int callingPid, int callingUid, int userId) { intent = new Intent(intent); // By default broadcasts do not go to stopped apps. intent.addFlags(Intent.FLAG_EXCLUDE_STOPPED_PACKAGES); // If we have not finished booting, don't allow this to launch new processes. if (!mProcessesReady && (intent.getFlags()&Intent.FLAG_RECEIVER_BOOT_UPGRADE) == 0) { intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY); } if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG_BROADCAST, (sticky ? "Broadcast sticky: ": "Broadcast: ") + intent + " ordered=" + ordered + " userid=" + userId); if ((resultTo != null) && !ordered) { Slog.w(TAG, "Broadcast " + intent + " not ordered but result callback requested!"); } userId = handleIncomingUser(callingPid, callingUid, userId, true, ALLOW_NON_FULL, "broadcast", callerPackage); // Make sure that the user who is receiving this broadcast is running. // If not, we will just skip it. Make an exception for shutdown broadcasts // and upgrade steps. if (userId != UserHandle.USER_ALL && !isUserRunningLocked(userId, false)) { if ((callingUid != Process.SYSTEM_UID || (intent.getFlags() & Intent.FLAG_RECEIVER_BOOT_UPGRADE) == 0) && !Intent.ACTION_SHUTDOWN.equals(intent.getAction())) { Slog.w(TAG, "Skipping broadcast of " + intent + ": user " + userId + " is stopped"); return ActivityManager.BROADCAST_FAILED_USER_STOPPED; } } BroadcastOptions brOptions = null; if (options != null) { brOptions = new BroadcastOptions(options); if (brOptions.getTemporaryAppWhitelistDuration() > 0) { // See if the caller is allowed to do this. Note we are checking against // the actual real caller (not whoever provided the operation as say a // PendingIntent), because that who is actually supplied the arguments. if (checkComponentPermission( android.Manifest.permission.CHANGE_DEVICE_IDLE_TEMP_WHITELIST, Binder.getCallingPid(), Binder.getCallingUid(), -1, true) != PackageManager.PERMISSION_GRANTED) { String msg = "Permission Denial: " + intent.getAction() + " broadcast from " + callerPackage + " (pid=" + callingPid + ", uid=" + callingUid + ")" + " requires " + android.Manifest.permission.CHANGE_DEVICE_IDLE_TEMP_WHITELIST; Slog.w(TAG, msg); throw new SecurityException(msg); } } } /* * Prevent non-system code (defined here to be non-persistent * processes) from sending protected broadcasts. */ int callingAppId = UserHandle.getAppId(callingUid); if (callingAppId == Process.SYSTEM_UID || callingAppId == Process.PHONE_UID || callingAppId == Process.SHELL_UID || callingAppId == Process.BLUETOOTH_UID || callingAppId == Process.NFC_UID || callingUid == 0) { // Always okay. } else if (callerApp == null || !callerApp.persistent) { try { if (AppGlobals.getPackageManager().isProtectedBroadcast( intent.getAction())) { String msg = "Permission Denial: not allowed to send broadcast " + intent.getAction() + " from pid=" + callingPid + ", uid=" + callingUid; Slog.w(TAG, msg); throw new SecurityException(msg); } else if (AppWidgetManager.ACTION_APPWIDGET_CONFIGURE.equals(intent.getAction())) { // Special case for compatibility: we don't want apps to send this, // but historically it has not been protected and apps may be using it // to poke their own app widget. So, instead of making it protected, // just limit it to the caller. if (callerApp == null) { String msg = "Permission Denial: not allowed to send broadcast " + intent.getAction() + " from unknown caller."; Slog.w(TAG, msg); throw new SecurityException(msg); } else if (intent.getComponent() != null) { // They are good enough to send to an explicit component... verify // it is being sent to the calling app. if (!intent.getComponent().getPackageName().equals( callerApp.info.packageName)) { String msg = "Permission Denial: not allowed to send broadcast " + intent.getAction() + " to " + intent.getComponent().getPackageName() + " from " + callerApp.info.packageName; Slog.w(TAG, msg); throw new SecurityException(msg); } } else { // Limit broadcast to their own package. intent.setPackage(callerApp.info.packageName); } } } catch (RemoteException e) { Slog.w(TAG, "Remote exception", e); return ActivityManager.BROADCAST_SUCCESS; } } final String action = intent.getAction(); if (action != null) { switch (action) { case Intent.ACTION_UID_REMOVED: case Intent.ACTION_PACKAGE_REMOVED: case Intent.ACTION_PACKAGE_CHANGED: case Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE: case Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE: // Handle special intents: if this broadcast is from the package // manager about a package being removed, we need to remove all of // its activities from the history stack. if (checkComponentPermission( android.Manifest.permission.BROADCAST_PACKAGE_REMOVED, callingPid, callingUid, -1, true) != PackageManager.PERMISSION_GRANTED) { String msg = "Permission Denial: " + intent.getAction() + " broadcast from " + callerPackage + " (pid=" + callingPid + ", uid=" + callingUid + ")" + " requires " + android.Manifest.permission.BROADCAST_PACKAGE_REMOVED; Slog.w(TAG, msg); throw new SecurityException(msg); } switch (action) { case Intent.ACTION_UID_REMOVED: final Bundle intentExtras = intent.getExtras(); final int uid = intentExtras != null ? intentExtras.getInt(Intent.EXTRA_UID) : -1; if (uid >= 0) { mBatteryStatsService.removeUid(uid); mAppOpsService.uidRemoved(uid); } break; case Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE: // If resources are unavailable just force stop all those packages // and flush the attribute cache as well. String list[] = intent.getStringArrayExtra(Intent.EXTRA_CHANGED_PACKAGE_LIST); if (list != null && list.length > 0) { for (int i = 0; i < list.length; i++) { forceStopPackageLocked(list[i], -1, false, true, true, false, false, userId, "storage unmount"); } mRecentTasks.cleanupLocked(UserHandle.USER_ALL); sendPackageBroadcastLocked( IApplicationThread.EXTERNAL_STORAGE_UNAVAILABLE, list, userId); } break; case Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE: mRecentTasks.cleanupLocked(UserHandle.USER_ALL); break; case Intent.ACTION_PACKAGE_REMOVED: case Intent.ACTION_PACKAGE_CHANGED: Uri data = intent.getData(); String ssp; if (data != null && (ssp=data.getSchemeSpecificPart()) != null) { boolean removed = Intent.ACTION_PACKAGE_REMOVED.equals(action); boolean fullUninstall = removed && !intent.getBooleanExtra(Intent.EXTRA_REPLACING, false); if (!intent.getBooleanExtra(Intent.EXTRA_DONT_KILL_APP, false)) { forceStopPackageLocked(ssp, UserHandle.getAppId( intent.getIntExtra(Intent.EXTRA_UID, -1)), false, true, true, false, fullUninstall, userId, removed ? "pkg removed" : "pkg changed"); } if (removed) { sendPackageBroadcastLocked(IApplicationThread.PACKAGE_REMOVED, new String[] {ssp}, userId); if (fullUninstall) { mAppOpsService.packageRemoved( intent.getIntExtra(Intent.EXTRA_UID, -1), ssp); // Remove all permissions granted from/to this package removeUriPermissionsForPackageLocked(ssp, userId, true); removeTasksByPackageNameLocked(ssp, userId); mBatteryStatsService.notePackageUninstalled(ssp); } } else { cleanupDisabledPackageComponentsLocked(ssp, userId, intent.getStringArrayExtra( Intent.EXTRA_CHANGED_COMPONENT_NAME_LIST)); } } break; } break; case Intent.ACTION_PACKAGE_ADDED: // Special case for adding a package: by default turn on compatibility mode. Uri data = intent.getData(); String ssp; if (data != null && (ssp = data.getSchemeSpecificPart()) != null) { final boolean replacing = intent.getBooleanExtra(Intent.EXTRA_REPLACING, false); mCompatModePackages.handlePackageAddedLocked(ssp, replacing); try { ApplicationInfo ai = AppGlobals.getPackageManager(). getApplicationInfo(ssp, 0, 0); mBatteryStatsService.notePackageInstalled(ssp, ai != null ? ai.versionCode : 0); } catch (RemoteException e) { } } break; case Intent.ACTION_TIMEZONE_CHANGED: // If this is the time zone changed action, queue up a message that will reset // the timezone of all currently running processes. This message will get // queued up before the broadcast happens. mHandler.sendEmptyMessage(UPDATE_TIME_ZONE); break; case Intent.ACTION_TIME_CHANGED: // If the user set the time, let all running processes know. final int is24Hour = intent.getBooleanExtra(Intent.EXTRA_TIME_PREF_24_HOUR_FORMAT, false) ? 1 : 0; mHandler.sendMessage(mHandler.obtainMessage(UPDATE_TIME, is24Hour, 0)); BatteryStatsImpl stats = mBatteryStatsService.getActiveStatistics(); synchronized (stats) { stats.noteCurrentTimeChangedLocked(); } break; case Intent.ACTION_CLEAR_DNS_CACHE: mHandler.sendEmptyMessage(CLEAR_DNS_CACHE_MSG); break; case Proxy.PROXY_CHANGE_ACTION: ProxyInfo proxy = intent.getParcelableExtra(Proxy.EXTRA_PROXY_INFO); mHandler.sendMessage(mHandler.obtainMessage(UPDATE_HTTP_PROXY_MSG, proxy)); break; } } // Add to the sticky list if requested. if (sticky) { if (checkPermission(android.Manifest.permission.BROADCAST_STICKY, callingPid, callingUid) != PackageManager.PERMISSION_GRANTED) { String msg = "Permission Denial: broadcastIntent() requesting a sticky broadcast from pid=" + callingPid + ", uid=" + callingUid + " requires " + android.Manifest.permission.BROADCAST_STICKY; Slog.w(TAG, msg); throw new SecurityException(msg); } if (requiredPermissions != null && requiredPermissions.length > 0) { Slog.w(TAG, "Can't broadcast sticky intent " + intent + " and enforce permissions " + Arrays.toString(requiredPermissions)); return ActivityManager.BROADCAST_STICKY_CANT_HAVE_PERMISSION; } if (intent.getComponent() != null) { throw new SecurityException( "Sticky broadcasts can't target a specific component"); } // We use userId directly here, since the "all" target is maintained // as a separate set of sticky broadcasts. if (userId != UserHandle.USER_ALL) { // But first, if this is not a broadcast to all users, then // make sure it doesn't conflict with an existing broadcast to // all users. ArrayMap<String, ArrayList<Intent>> stickies = mStickyBroadcasts.get( UserHandle.USER_ALL); if (stickies != null) { ArrayList<Intent> list = stickies.get(intent.getAction()); if (list != null) { int N = list.size(); int i; for (i=0; i<N; i++) { if (intent.filterEquals(list.get(i))) { throw new IllegalArgumentException( "Sticky broadcast " + intent + " for user " + userId + " conflicts with existing global broadcast"); } } } } } ArrayMap<String, ArrayList<Intent>> stickies = mStickyBroadcasts.get(userId); if (stickies == null) { stickies = new ArrayMap<>(); mStickyBroadcasts.put(userId, stickies); } ArrayList<Intent> list = stickies.get(intent.getAction()); if (list == null) { list = new ArrayList<>(); stickies.put(intent.getAction(), list); } final int stickiesCount = list.size(); int i; for (i = 0; i < stickiesCount; i++) { if (intent.filterEquals(list.get(i))) { // This sticky already exists, replace it. list.set(i, new Intent(intent)); break; } } if (i >= stickiesCount) { list.add(new Intent(intent)); } } int[] users; if (userId == UserHandle.USER_ALL) { // Caller wants broadcast to go to all started users. users = mStartedUserArray; } else { // Caller wants broadcast to go to one specific user. users = new int[] {userId}; } // Figure out who all will receive this broadcast. List receivers = null; List<BroadcastFilter> registeredReceivers = null; // Need to resolve the intent to interested receivers... if ((intent.getFlags()&Intent.FLAG_RECEIVER_REGISTERED_ONLY) == 0) { receivers = collectReceiverComponents(intent, resolvedType, callingUid, users); } if (intent.getComponent() == null) { if (userId == UserHandle.USER_ALL && callingUid == Process.SHELL_UID) { // Query one target user at a time, excluding shell-restricted users UserManagerService ums = getUserManagerLocked(); for (int i = 0; i < users.length; i++) { if (ums.hasUserRestriction( UserManager.DISALLOW_DEBUGGING_FEATURES, users[i])) { continue; } List<BroadcastFilter> registeredReceiversForUser = mReceiverResolver.queryIntent(intent, resolvedType, false, users[i]); if (registeredReceivers == null) { registeredReceivers = registeredReceiversForUser; } else if (registeredReceiversForUser != null) { registeredReceivers.addAll(registeredReceiversForUser); } } } else { registeredReceivers = mReceiverResolver.queryIntent(intent, resolvedType, false, userId); } } final boolean replacePending = (intent.getFlags()&Intent.FLAG_RECEIVER_REPLACE_PENDING) != 0; if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Enqueing broadcast: " + intent.getAction() + " replacePending=" + replacePending); int NR = registeredReceivers != null ? registeredReceivers.size() : 0; if (!ordered && NR > 0) { // If we are not serializing this broadcast, then send the // registered receivers separately so they don't wait for the // components to be launched. final BroadcastQueue queue = broadcastQueueForIntent(intent); BroadcastRecord r = new BroadcastRecord(queue, intent, callerApp, callerPackage, callingPid, callingUid, resolvedType, requiredPermissions, appOp, brOptions, registeredReceivers, resultTo, resultCode, resultData, resultExtras, ordered, sticky, false, userId); if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Enqueueing parallel broadcast " + r); final boolean replaced = replacePending && queue.replaceParallelBroadcastLocked(r); if (!replaced) { queue.enqueueParallelBroadcastLocked(r); queue.scheduleBroadcastsLocked(); } registeredReceivers = null; NR = 0; } // Merge into one list. int ir = 0; if (receivers != null) { // A special case for PACKAGE_ADDED: do not allow the package // being added to see this broadcast. This prevents them from // using this as a back door to get run as soon as they are // installed. Maybe in the future we want to have a special install // broadcast or such for apps, but we'd like to deliberately make // this decision. String skipPackages[] = null; if (Intent.ACTION_PACKAGE_ADDED.equals(intent.getAction()) || Intent.ACTION_PACKAGE_RESTARTED.equals(intent.getAction()) || Intent.ACTION_PACKAGE_DATA_CLEARED.equals(intent.getAction())) { Uri data = intent.getData(); if (data != null) { String pkgName = data.getSchemeSpecificPart(); if (pkgName != null) { skipPackages = new String[] { pkgName }; } } } else if (Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE.equals(intent.getAction())) { skipPackages = intent.getStringArrayExtra(Intent.EXTRA_CHANGED_PACKAGE_LIST); } if (skipPackages != null && (skipPackages.length > 0)) { for (String skipPackage : skipPackages) { if (skipPackage != null) { int NT = receivers.size(); for (int it=0; it<NT; it++) { ResolveInfo curt = (ResolveInfo)receivers.get(it); if (curt.activityInfo.packageName.equals(skipPackage)) { receivers.remove(it); it--; NT--; } } } } } int NT = receivers != null ? receivers.size() : 0; int it = 0; ResolveInfo curt = null; BroadcastFilter curr = null; while (it < NT && ir < NR) { if (curt == null) { curt = (ResolveInfo)receivers.get(it); } if (curr == null) { curr = registeredReceivers.get(ir); } if (curr.getPriority() >= curt.priority) { // Insert this broadcast record into the final list. receivers.add(it, curr); ir++; curr = null; it++; NT++; } else { // Skip to the next ResolveInfo in the final list. it++; curt = null; } } } while (ir < NR) { if (receivers == null) { receivers = new ArrayList(); } receivers.add(registeredReceivers.get(ir)); ir++; } if ((receivers != null && receivers.size() > 0) || resultTo != null) { BroadcastQueue queue = broadcastQueueForIntent(intent); BroadcastRecord r = new BroadcastRecord(queue, intent, callerApp, callerPackage, callingPid, callingUid, resolvedType, requiredPermissions, appOp, brOptions, receivers, resultTo, resultCode, resultData, resultExtras, ordered, sticky, false, userId); if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Enqueueing ordered broadcast " + r + ": prev had " + queue.mOrderedBroadcasts.size()); if (DEBUG_BROADCAST) Slog.i(TAG_BROADCAST, "Enqueueing broadcast " + r.intent.getAction()); boolean replaced = replacePending && queue.replaceOrderedBroadcastLocked(r); if (!replaced) { queue.enqueueOrderedBroadcastLocked(r); queue.scheduleBroadcastsLocked(); } } return ActivityManager.BROADCAST_SUCCESS; }
processNextBroadcast内容如下
1.如果广播接收者为动态注册对象，则直接调用deliverToRegisteredReceiverLocked处理它
2.如果广播接收者为静态注册对象，并且该对象对应的进程已经存在，则调用processCurBroadcastLocked处理它
3.如果广播接收者为静态注册对象，并且该对象对应的进程还不存在，则需要创建该进程，这是最糟糕的情况
public void finishReceiver(IBinder who, int resultCode, String resultData, Bundle resultExtras, boolean resultAbort, int flags) { if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Finish receiver: " + who); // Refuse possible leaked file descriptors if (resultExtras != null && resultExtras.hasFileDescriptors()) { throw new IllegalArgumentException("File descriptors passed in Bundle"); } final long origId = Binder.clearCallingIdentity(); try { boolean doNext = false; BroadcastRecord r; synchronized(this) { BroadcastQueue queue = (flags & Intent.FLAG_RECEIVER_FOREGROUND) != 0 ? mFgBroadcastQueue : mBgBroadcastQueue; r = queue.getMatchingOrderedReceiver(who); if (r != null) { doNext = r.queue.finishReceiverLocked(r, resultCode, resultData, resultExtras, resultAbort, true); } } if (doNext) { r.queue.processNextBroadcast(false); } trimApplications(); } finally { Binder.restoreCallingIdentity(origId); } }
Service服务
Service非常服务C/S架构中的Service的概念，即为Client服务，处理Client的请求。在Android中，目前接触最多的是Binder中的C/S架构。在这种架构中，Client通过调用预先定义好的业务函数向对应的Service发送请求。Service响应Client的请求有两种方式
1.Client通过调用startService向Service端发送一个Intent，该Intent携带请求信息。而Service的onStartCommand会接收该Intent，并处理之。该方式是Android平台特有的，借助Intent来传递请求。
2.Client调用bindService函数和一个指定的Service建立Binder关系，即绑定成功后，Client端将得到处理业务逻辑的Binder Bp端。此后Client直接调用Bp端提供的业务函数向Service端发出请求。注意，在这种方式中，Service的onBind函数被调用，如果该Service支持Binder，则需返回一个IBinder对象给客户端