《深入理解Android2》读书笔记（七）

接上篇《深入理解Android2》读书笔记（六）

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