上篇博客大致说了说广播的注册机制，动态注册和静态注册广播的原理还不1样，动态广播最后HashMap中了，最后放到mReceiverResolver中，
以后当ActivityManagerService接收到广播的时候，它就能够再成员变量mReceiverResolver中找到对应的广播接收者了。下面我们来讲说广播的发送机制。
广播发送时候，在Context.java的方法中调用的，有以下方法：
sendBroadcast(Intent intent) ；
sendBroadcast(Intent intent, String receiverPermission)
sendBroadcastAsUser(Intent intent, UserHandle user)
sendBroadcastAsUser(Intent intent, UserHandle user, String receiverPermission)
sendOrderedBroadcast(Intent intent, String receiverPermission)
sendOrderedBroadcastAsUser(Intent intent, UserHandle user, String receiverPermission, BroadcastReceiver resultReceiver, Handler scheduler, int initialCode, String initialData, Bundle initialExtras)
sendStickyBroadcast(Intent intent)
sendStickyBroadcastAsUser(Intent intent, UserHandle user)
sendStickyOrderedBroadcast(Intent intent, BroadcastReceiver resultReceiver, Handler scheduler, int initialCode, String initialData, Bundle initialExtras)
sendStickyOrderedBroadcastAsUser(Intent intent, UserHandle user, BroadcastReceiver resultReceiver, Handler scheduler, int initialCode, String initialData, Bundle initialExtras)
以上就是发送广播的方式，但是经常使用的就几种，其中比较经常使用的就是sendBroadcast(Intent intent) ；我就说下这类发送广播的方式。
sendBroadcast在context中调用的，往下调用到了ContextImpl.java中去了：
/**
* Common implementation of Context API, which provides the base
* context object for Activity and other application components.
*/
class ContextImpl extends Context {
private final static String TAG = "ContextImpl";
private final static boolean DEBUG = false;
@Override
public void sendBroadcast(Intent intent, String receiverPermission) {
warnIfCallingFromSystemProcess();
String resolvedType = intent.resolveTypeIfNeeded(getContentResolver());
try {
intent.prepareToLeaveProcess();
ActivityManagerNative.getDefault().broadcastIntent(
mMainThread.getApplicationThread(), intent, resolvedType, null,
Activity.RESULT_OK, null, null, receiverPermission, AppOpsManager.OP_NONE,
false, false, getUserId());
} catch (RemoteException e) {
}
}调用到了ActivityManagerService.java中的broadcastIntent（）方法中去了，
public final int broadcastIntent(IApplicationThread caller,
Intent intent, String resolvedType, IIntentReceiver resultTo,int resultCode, String resultData, Bundle map, String requiredPermission, int appOp, boolean serialized, boolean sticky, int userId) {
enforceNotIsolatedCaller("broadcastIntent");
synchronized(this) {
//校验广播是不是锁定
intent = verifyBroadcastLocked(intent);
final ProcessRecord callerApp = getRecordForAppLocked(caller);
final int callingPid = Binder.getCallingPid();
final int callingUid = Binder.getCallingUid();
final long origId = Binder.clearCallingIdentity();
int res = broadcastIntentLocked(callerApp,
callerApp != null ? callerApp.info.packageName : null,
intent, resolvedType, resultTo,
resultCode, resultData, map, requiredPermission, appOp, serialized, sticky,
callingPid, callingUid, userId);
Binder.restoreCallingIdentity(origId);
return res;
}
}这个方法有点复杂，逻辑量有点大
private final int broadcastIntentLocked(ProcessRecord callerApp, String callerPackage, Intent intent, String resolvedType, IIntentReceiver resultTo, int resultCode, String resultData, Bundle map, String requiredPermission, int appOp, boolean ordered, boolean sticky, int callingPid, int callingUid, int userId) {
intent = new Intent(intent);
// By default broadcasts do not go to stopped apps.
1)如果apk被forceStop（）强行停止或安装后就没有启动过，这个apk就处于停 止状态（stopped state）
===============================================================
intent.addFlags(Intent.FLAG_EXCLUDE_STOPPED_PACKAGES);
if (DEBUG_BROADCAST_LIGHT) Slog.v(
TAG, (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 started.
// If not, we will just skip it.
if (userId != UserHandle.USER_ALL && mStartedUsers.get(userId) == null) {
if (callingUid != Process.SYSTEM_UID || (intent.getFlags() & Intent.FLAG_RECEIVER_BOOT_UPGRADE) == 0){
Slog.w(TAG, "Skipping broadcast of " + intent + ": user " + userId + " is stopped");
return ActivityManager.BROADCAST_SUCCESS;
}
}
2）判断当前是不是有权利发出广播
===============
/*
* 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;
}
}
3）处理和package相干的广播，如果这个package被卸载了，我们也要相应地移除它所有的组件
=================================================
// 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.
final boolean uidRemoved = Intent.ACTION_UID_REMOVED.equals(
intent.getAction());
if (Intent.ACTION_PACKAGE_REMOVED.equals(intent.getAction())
|| Intent.ACTION_PACKAGE_CHANGED.equals(intent.getAction())
|| Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE.equals(intent.getAction())
|| Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE.equals(intent.getAction())
|| uidRemoved) {
if (checkComponentPermission(
android.Manifest.permission.BROADCAST_PACKAGE_REMOVED,
callingPid, callingUid, -1, true)
== PackageManager.PERMISSION_GRANTED) {
if (uidRemoved) {
final Bundle intentExtras = intent.getExtras();
final int uid = intentExtras != null
? intentExtras.getInt(Intent.EXTRA_UID) : -1;
if (uid >= 0) {
BatteryStatsImpl bs = mBatteryStatsService.getActiveStatistics();
synchronized (bs) {
bs.removeUidStatsLocked(uid);
}
mAppOpsService.uidRemoved(uid);
}
} else {
// If resources are unavailable just force stop all
// those packages and flush the attribute cache as well.
if (Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE.equals(intent.getAction())) {
String list[] = intent.getStringArrayExtra(Intent.EXTRA_CHANGED_PACKAGE_LIST);
if (list != null && (list.length > 0)) {
for (String pkg : list) {
forceStopPackageLocked(pkg, -1, false, true, true, false, false, userId,
"storage unmount");
}
cleanupRecentTasksLocked(UserHandle.USER_ALL);
sendPackageBroadcastLocked(
IApplicationThread.EXTERNAL_STORAGE_UNAVAILABLE, list, userId);
}
} else if (Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE.equals(
intent.getAction())) {
cleanupRecentTasksLocked(UserHandle.USER_ALL);
} else {
Uri data = intent.getData();
String ssp;
if (data != null && (ssp=data.getSchemeSpecificPart()) != null) {
boolean removed = Intent.ACTION_PACKAGE_REMOVED.equals(
intent.getAction());
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 (!intent.getBooleanExtra(Intent.EXTRA_REPLACING, false)) {
mAppOpsService.packageRemoved(
intent.getIntExtra(Intent.EXTRA_UID, -1), ssp);
// Remove all permissions granted from/to this package removeUriPermissionsForPackageLocked(ssp, userId, true);
}
}
}
}
}
} else {
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);
}
// Special case for adding a package: by default turn on compatibility
// mode.
} else if (Intent.ACTION_PACKAGE_ADDED.equals(intent.getAction())) {
Uri data = intent.getData();
String ssp;
if (data != null && (ssp=data.getSchemeSpecificPart()) != null) {
mCompatModePackages.handlePackageAddedLocked(ssp,
intent.getBooleanExtra(Intent.EXTRA_REPLACING, false));
}
}
4）处理其他1些系统广播ACTION_TIMEZONE_CHANGED，ACTION_TIME_CHANGED，PROXY_CHANGE_ACTION，
========================================================================
/*
* 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.
*/
if (Intent.ACTION_TIMEZONE_CHANGED.equals(intent.getAction())) {
mHandler.sendEmptyMessage(UPDATE_TIME_ZONE);
}
/*
* If the user set the time, let all running processes know.
*/
if (Intent.ACTION_TIME_CHANGED.equals(intent.getAction())) {
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();
}
}
if (Intent.ACTION_CLEAR_DNS_CACHE.equals(intent.getAction())) {
mHandler.sendEmptyMessage(CLEAR_DNS_CACHE_MSG);
}
if (Proxy.PROXY_CHANGE_ACTION.equals(intent.getAction())) {
ProxyInfo proxy = intent.getParcelableExtra(Proxy.EXTRA_PROXY_INFO);
mHandler.sendMessage(mHandler.obtainMessage(UPDATE_HTTP_PROXY_MSG, proxy));
}
5）判断广播是不是是1个黏性广播，所有相同类型的黏性广播保存起到1个列表中，最后会保存到mStickyBroadcasts这个HashMap中。
======================================
// 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 (requiredPermission != null) {
Slog.w(TAG, "Can't broadcast sticky intent " + intent
+ " and enforce permission " + requiredPermission);
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<String, ArrayList<Intent>>();
mStickyBroadcasts.put(userId, stickies);
}
ArrayList<Intent> list = stickies.get(intent.getAction());
if (list == null) {
list = new ArrayList<Intent>();
stickies.put(intent.getAction(), list);
}
int N = list.size();
int i;
for (i=0; i<N; i++) {
if (intent.filterEquals(list.get(i))) {
// This sticky already exists, replace it.
list.set(i, new Intent(intent));
break;
}
}
if (i >= N) {
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};
}
6）先查询静态广播保存到receivers中，再查询动态广播保存到registeredReceivers中
=====================================================
//找出谁都会收到这个广播。
// Figure out who all will receive this broadcast.
List receivers = null;
List<BroadcastFilter> registeredReceivers = null;
// Need to resolve the intent to interested receivers...
//如果下面的if语句为true，表示找到所有静态的广播保存到receivers 中
if ((intent.getFlags()&Intent.FLAG_RECEIVER_REGISTERED_ONLY)
== 0) {
receivers = collectReceiverComponents(intent, resolvedType, callingUid, users);
}
//如果if：true，则queryIntent查询所有匹配intent的Receiver;
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) {
// 表示找到所有动态的广播保存到registeredReceivers中
registeredReceivers.addAll(registeredReceiversForUser);
}
}
} else {
registeredReceivers = mReceiverResolver.queryIntent(intent,
resolvedType, false, userId);
}
}
7）广播的调度，和广播的分发
=======
//是不是替换上1个相同的广播，即：上次接受的1个广播还未来得及转发给接收者，
//又马上发送了1个相同的广播。这这类情况下接受的getFlags（）==1，
//表示要替换旧的广播，即replacePending = true；
final boolean replacePending = (intent.getFlags()&Intent.FLAG_RECEIVER_REPLACE_PENDING) != 0;
if (DEBUG_BROADCAST) Slog.v(TAG, "Enqueing broadcast: " + intent.getAction()
+ " replacePending=" + replacePending);
int NR = registeredReceivers != null ? registeredReceivers.size() : 0;
//ordered表示是不是是1个无序的广播,并且是registeredReceivers动态广播
//这就说明动态广播要优先于静态广播的注册者
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, requiredPermission, appOp, registeredReceivers, resultTo, resultCode, resultData, map, ordered, sticky, false, userId);
if (DEBUG_BROADCAST) Slog.v(
TAG, "Enqueueing parallel broadcast " + r);
final boolean replaced = replacePending && queue.replaceParallelBroadcastLocked(r);
if (!replaced) {
//这个做了修改，把无序广播的调度队列封装到BroadcastQueue.java这个类中
//去了，mParallelBroadcasts来表示
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.
8）合并静态广播receivers和静态广播registerReceivers列表为1个列表
=======
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;
//合并动态广播和静态广播，合并前它们都是依照优先级排好序的，
//根据优先级来进行合并的算法@{
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;
}
}
//合并动态广播和静态广播，根据优先级来进行合并的算法@}
}
//如果没有完全把registeredReceivers列表中的数据合并到receivers中，
//就用while循环顺次添加到recivers的末尾，由于它们是优先级最低的广播接收者
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,
requiredPermission, appOp, receivers, resultTo, resultCode,
resultData, map, ordered, sticky, false, userId);
if (DEBUG_BROADCAST) Slog.v(
TAG, "Enqueueing ordered broadcast " + r
+ ": prev had " + queue.mOrderedBroadcasts.size());
if (DEBUG_BROADCAST) {
int seq = r.intent.getIntExtra("seq", -1);
Slog.i(TAG, "Enqueueing broadcast " + r.intent.getAction() + " seq=" + seq);
}
boolean replaced = replacePending && queue.replaceOrderedBroadcastLocked(r);
if (!replaced) {
//广播的分发，真正发送广播的地方在BroadcastQueue.java中履行的
queue.enqueueOrderedBroadcastLocked(r);
queue.scheduleBroadcastsLocked();
}
}
return ActivityManager.BROADCAST_SUCCESS;
}public void scheduleBroadcastsLocked() {
if (DEBUG_BROADCAST) Slog.v(TAG, "Schedule broadcasts ["
+ mQueueName + "]: current="
+ mBroadcastsScheduled);
if (mBroadcastsScheduled) {
return;
}
//这个方法比较简单，就发送了1个消息 BROADCAST_INTENT_MSG mHandler.sendMessage(mHandler.obtainMessage(BROADCAST_INTENT_MSG, this));
mBroadcastsScheduled = true;
}private final class BroadcastHandler extends Handler {
public BroadcastHandler(Looper looper) {
super(looper, null, true);
}
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case BROADCAST_INTENT_MSG: {
if (DEBUG_BROADCAST) Slog.v(
TAG, "Received BROADCAST_INTENT_MSG");
processNextBroadcast(true);
} break;
case BROADCAST_TIMEOUT_MSG: {
synchronized (mService) {
broadcastTimeoutLocked(true);
}
} break;
}
}
};以上方法履行processNextBroadcast(true);这个是最重要的调用广播发送的方法了。
final void processNextBroadcast(boolean fromMsg) {
synchronized(mService) {
BroadcastRecord r;
if (DEBUG_BROADCAST) Slog.v(TAG, "processNextBroadcast ["
+ mQueueName + "]: "
+ mParallelBroadcasts.size() + " broadcasts, " + mOrderedBroadcasts.size() + " ordered broadcasts");
mService.updateCpuStats();
if (fromMsg) {
//这个表示前面的Scheduled还没有履行，handleMessage中会接着处理
mBroadcastsScheduled = false;
}
// First, deliver any non-serialized broadcasts right away.
//mParallelBroadcasts这个就是1个无序的广播调度队列
while (mParallelBroadcasts.size() > 0) {
r = mParallelBroadcasts.remove(0);
r.dispatchTime = SystemClock.uptimeMillis();
r.dispatchClockTime = System.currentTimeMillis();
final int N = r.receivers.size();
if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG, "Processing parallel broadcast ["
+ mQueueName + "] " + r);
for (int i=0; i<N; i++) {
Object target = r.receivers.get(i);
if (DEBUG_BROADCAST) Slog.v(TAG,
"Delivering non-ordered on [" + mQueueName + "] to registered "
+ target + ": " + r);
//调用无序广播
deliverToRegisteredReceiverLocked(r, (BroadcastFilter)target, false);
}
addBroadcastToHistoryLocked(r);
if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG, "Done with parallel broadcast ["
+ mQueueName + "] " + r);
}
// Now take care of the next serialized one...
// If we are waiting for a process to come up to handle the next
// broadcast, then do nothing at this point. Just in case, we
// check that the process we're waiting for still exists.
//mPendingBroadcast 描写的广播的接收者有多是静态注册的。
if (mPendingBroadcast != null) {
if (DEBUG_BROADCAST_LIGHT) {
Slog.v(TAG, "processNextBroadcast ["
+ mQueueName + "]: waiting for "
+ mPendingBroadcast.curApp);
}
boolean isDead;
synchronized (mService.mPidsSelfLocked) {
ProcessRecord proc = mService.mPidsSelfLocked.get(mPendingBroadcast.curApp.pid);
isDead = proc == null || proc.crashing;
}
//如果它运行中，保持等待
if (!isDead) {
// It's still alive, so keep waiting
return;
} else {
Slog.w(TAG, "pending app [" + mQueueName + "]" + mPendingBroadcast.curApp + " died before responding to broadcast");
mPendingBroadcast.state = BroadcastRecord.IDLE;
//如果它没有运行，就准备给它发送1个广播mPendingBroadcastRecvIndex
mPendingBroadcast.nextReceiver = mPendingBroadcastRecvIndex;
mPendingBroadcast = null;
}
}
boolean looped = false;
//有序广播mOrderedBroadcasts的调度任务的处理
do {
if (mOrderedBroadcasts.size() == 0) {
// No more broadcasts pending, so all done!
mService.scheduleAppGcsLocked();
if (looped) {
// If we had finished the last ordered broadcast, then
// make sure all processes have correct oom and sched
// adjustments.
mService.updateOomAdjLocked();
}
return;
}
r = mOrderedBroadcasts.get(0);
boolean forceReceive = false;
// Ensure that even if something goes awry with the timeout
// detection, we catch "hung" broadcasts here, discard them,
// and continue to make progress.
//
// This is only done if the system is ready so that PRE_BOOT_COMPLETED
// receivers don't get executed with timeouts. They're intended for
// one time heavy lifting after system upgrades and can take
// significant amounts of time.
int numReceivers = (r.receivers != null) ? r.receivers.size() : 0;
if (mService.mProcessesReady && r.dispatchTime > 0) {
long now = SystemClock.uptimeMillis();
//检查广播的的处理时间是不是在规定的时间完成
if ((numReceivers > 0) &&
(now > r.dispatchTime + (2*mTimeoutPeriod*numReceivers))) {
Slog.w(TAG, "Hung broadcast [" + mQueueName + "] discarded after timeout failure:"+ " now=" + now + " dispatchTime=" + r.dispatchTime + " startTime=" + r.receiverTime + " intent=" + r.intent + " numReceivers=" + numReceivers + " nextReceiver=" + r.nextReceiver + " state=" + r.state);
//置为idle状态。
broadcastTimeoutLocked(false);
// forcibly finish this broadcast
forceReceive = true;
r.state = BroadcastRecord.IDLE;
}
}
if (r.state != BroadcastRecord.IDLE) {
if (DEBUG_BROADCAST) Slog.d(TAG,
"processNextBroadcast("
+ mQueueName + ") called when not idle (state="
+ r.state + ")");
return;
}
if (r.receivers == null || r.nextReceiver >= numReceivers
|| r.resultAbort || forceReceive) {
// No more receivers for this broadcast! Send the final
// result if requested...
if (r.resultTo != null) {
try {
if (DEBUG_BROADCAST) {
int seq = r.intent.getIntExtra("seq", -1);
Slog.i(TAG, "Finishing broadcast ["
+ mQueueName + "] " + r.intent.getAction()
+ " seq=" + seq + " app=" + r.callerApp);
+ performReceiveLocked(r.callerApp, r.resultTo,
new Intent(r.intent), r.resultCode, r.resultData,
r.resultExtras, false, false, r.userId);
// Set this to null so that the reference
// (local and remote) isn't kept in the mBroadcastHistory.
r.resultTo = null;
} catch (RemoteException e) {
r.resultTo = null;
Slog.w(TAG, "Failure ["
+ mQueueName + "] sending broadcast result of "
+ r.intent, e);
}
}
if (DEBUG_BROADCAST) Slog.v(TAG, "Cancelling BROADCAST_TIMEOUT_MSG");
//取消广播删除BROADCAST_TIMEOUT_MSG这个消息
cancelBroadcastTimeoutLocked();
if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG, "Finished with ordered broadcast " + r);
// ... and on to the next...
addBroadcastToHistoryLocked(r);
mOrderedBroadcasts.remove(0);
r = null;
looped = true;
continue;
}
} while (r == null);
// Get the next receiver...
//获得下1个广播
int recIdx = r.nextReceiver++;
// Keep track of when this receiver started, and make sure there
// is a timeout message pending to kill it if need be.
r.receiverTime = SystemClock.uptimeMillis();
if (recIdx == 0) {
r.dispatchTime = r.receiverTime;
r.dispatchClockTime = System.currentTimeMillis();
if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG, "Processing ordered broadcast ["
+ mQueueName + <