本次源碼基于Android11分析
相關(guān)源碼：
/frameworks/base/core/java/android/content/ContextWrapper.java
/frameworks/base/core/java/android/app/ContextImpl.java
/frameworks/base/core/java/android/app/LoadedApk.java
/frameworks/base/services/core/java/com/android/server/am/ActivityManagerService.java
/frameworks/base/services/core/java/com/android/server/am/BroadcastQueue.java
/frameworks/base/core/java/android/app/ActivityThread.java
廣播的注冊(cè)
廣播的注冊(cè)分為：靜態(tài)注冊(cè)和動(dòng)態(tài)注冊(cè)。靜態(tài)注冊(cè)是在AndroidManifest文件中注冊(cè)廣播接收器BroadcastReceiver和intent-filter,然后在安裝的時(shí)候通過(guò)PKMS進(jìn)行解析。動(dòng)態(tài)注冊(cè)則通過(guò)Context.registerReceiver向AMS注冊(cè)廣播接收器BroadcastReceiver和IntentFilter。
- 通過(guò)繼承BroadcastReceiver創(chuàng)建一個(gè)廣播接收器
class MyBroadcastReceiver : BroadcastReceiver() {
override fun onReceive(p0: Context?, p1: Intent?) {
}
}
- 靜態(tài)注冊(cè)廣播接收器
<receiver android:name=".MyBroadcastReceiver" android:enabled="true" android:exported="true"> <intent-filter> <action android:name="com.example.blogBroadcasts.MY_BROADCAS" /> </intent-filter> </receiver> - 動(dòng)態(tài)注冊(cè)廣播接收器
// 動(dòng)態(tài)注冊(cè)廣播
val intentFilter = IntentFilter(ACTION)
val broadcastReceiver = MyBroadcastReceiver()
registerReceiver(broadcastReceiver, intentFilter)
以下講講動(dòng)態(tài)注冊(cè)廣播接收器的過(guò)程：
動(dòng)態(tài)注冊(cè)廣播接收器
動(dòng)態(tài)注冊(cè)是把BroadcastReceiver包裝成一個(gè)Binder對(duì)象，然后創(chuàng)建一個(gè)包含BroadcastReceiver和IntentFilter的BroadcastFilter對(duì)象，然后把BroadcastFilter對(duì)象加入到AMS的mReceiverResolver變量中。動(dòng)態(tài)的注冊(cè)的大致流程圖如下：
通過(guò)Context的注冊(cè)處理：
public class ContextWrapper extends Context {
Context mBase;
@Override
public Intent registerReceiver(
BroadcastReceiver receiver, IntentFilter filter) {
// 調(diào)用ContextImpl.registerReceiver()方法
return mBase.registerReceiver(receiver, filter);
}
@Override
public Intent registerReceiver(
BroadcastReceiver receiver, IntentFilter filter, int flags) {
return mBase.registerReceiver(receiver, filter, flags);
}
@Override
public Intent registerReceiver(
BroadcastReceiver receiver, IntentFilter filter,
String broadcastPermission, Handler scheduler) {
return mBase.registerReceiver(receiver, filter, broadcastPermission,
scheduler);
}
@Override
public Intent registerReceiver(
BroadcastReceiver receiver, IntentFilter filter,
String broadcastPermission, Handler scheduler, int flags) {
return mBase.registerReceiver(receiver, filter, broadcastPermission,
scheduler, flags);
}
}
class ContextImpl extends Context {
final LoadedApk mPackageInfo;
@Override
public Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter) {
return registerReceiver(receiver, filter, null, null);
}
@Override
public Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter,
int flags) {
return registerReceiver(receiver, filter, null, null, flags);
}
@Override
public Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter,
String broadcastPermission, Handler scheduler) {
// 最后調(diào)用registerReceiverInternal()方法
return registerReceiverInternal(receiver, getUserId(),
filter, broadcastPermission, scheduler, getOuterContext(), 0);
}
@Override
public Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter,
String broadcastPermission, Handler scheduler, int flags) {
// 最后調(diào)用registerReceiverInternal()方法
return registerReceiverInternal(receiver, getUserId(),
filter, broadcastPermission, scheduler, getOuterContext(), flags);
}
private Intent registerReceiverInternal(BroadcastReceiver receiver, int userId,
IntentFilter filter, String broadcastPermission,
Handler scheduler, Context context, int flags) {
IIntentReceiver rd = null;
// 將BroadcastReceiver存儲(chǔ)到LoadedApk.ReceiverDispatcher對(duì)象里，
// 并通過(guò)LoadedApk.ReceiverDispatcher.InnerReceiver的Binder對(duì)象和AMS進(jìn)行通信
if (receiver != null) {
if (mPackageInfo != null && context != null) {
if (scheduler == null) {
scheduler = mMainThread.getHandler();
}
// 獲取IntentReceiver Binder對(duì)象
rd = mPackageInfo.getReceiverDispatcher(
receiver, context, scheduler,
mMainThread.getInstrumentation(), true);
} else {
if (scheduler == null) {
scheduler = mMainThread.getHandler();
}
// 獲取IntentReceiver Binder對(duì)象
rd = new LoadedApk.ReceiverDispatcher(
receiver, context, scheduler, null, true).getIIntentReceiver();
}
}
try {
// 調(diào)用AMS.registerReceiverWithFeature
final Intent intent = ActivityManager.getService().registerReceiverWithFeature(
mMainThread.getApplicationThread(), mBasePackageName, getAttributionTag(), rd,
filter, broadcastPermission, userId, flags);
if (intent != null) {
intent.setExtrasClassLoader(getClassLoader());
intent.prepareToEnterProcess();
}
return intent;
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
}
public final class LoadedApk {
public IIntentReceiver getReceiverDispatcher(BroadcastReceiver r,
Context context, Handler handler,
Instrumentation instrumentation, boolean registered) {
synchronized (mReceivers) {
// 先嘗試從緩存中獲取，緩存中沒(méi)有則new一個(gè)
LoadedApk.ReceiverDispatcher rd = null;
ArrayMap<BroadcastReceiver, LoadedApk.ReceiverDispatcher> map = null;
if (registered) {
map = mReceivers.get(context);
if (map != null) {
rd = map.get(r);
}
}
if (rd == null) {
rd = new ReceiverDispatcher(r, context, handler,
instrumentation, registered);
if (registered) {
if (map == null) {
map = new ArrayMap<BroadcastReceiver, LoadedApk.ReceiverDispatcher>();
mReceivers.put(context, map);
}
map.put(r, rd);
}
} else {
rd.validate(context, handler);
}
rd.mForgotten = false;
// 獲取內(nèi)部類Binder對(duì)象
return rd.getIIntentReceiver();
}
}
static final class ReceiverDispatcher {
final IIntentReceiver.Stub mIIntentReceiver;
final BroadcastReceiver mReceiver;
@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)
final Context mContext;
final Handler mActivityThread;
final Instrumentation mInstrumentation;
final boolean mRegistered;
final IntentReceiverLeaked mLocation;
RuntimeException mUnregisterLocation;
boolean mForgotten;
ReceiverDispatcher(BroadcastReceiver receiver, Context context,
Handler activityThread, Instrumentation instrumentation,
boolean registered) {
if (activityThread == null) {
throw new NullPointerException("Handler must not be null");
}
mIIntentReceiver = new InnerReceiver(this, !registered);
mReceiver = receiver;
mContext = context;
mActivityThread = activityThread;
mInstrumentation = instrumentation;
mRegistered = registered;
mLocation = new IntentReceiverLeaked(null);
mLocation.fillInStackTrace();
}
// 獲取InnerReceiver的Binder類
IIntentReceiver getIIntentReceiver() {
return mIIntentReceiver;
}
final static class InnerReceiver extends IIntentReceiver.Stub {
final WeakReference<ReceiverDispatcher> mDispatcher;
final LoadedApk.ReceiverDispatcher mStrongRef;
InnerReceiver(LoadedApk.ReceiverDispatcher rd, boolean strong) {
mDispatcher = new WeakReference<LoadedApk.ReceiverDispatcher>(rd);
mStrongRef = strong ? rd : null;
}
@Override
public void performReceive(Intent intent, int resultCode, String data,
Bundle extras, boolean ordered, boolean sticky, int sendingUser) {
final LoadedApk.ReceiverDispatcher rd;
//...
// 調(diào)用ReceiverDispatcher.performReceive方法
if (rd != null) {
rd.performReceive(intent, resultCode, data, extras,
ordered, sticky, sendingUser);
}
}
}
}
}
將BroadcastReceiver包裝成一個(gè)Binder對(duì)象，用于與AMS的回調(diào)通信，最后調(diào)用AMS.registerReceiverWithFeature方法。
AMS處理動(dòng)態(tài)注冊(cè)廣播
public class ActivityManagerService extends IActivityManager.Stub {
public Intent registerReceiverWithFeature(IApplicationThread caller, String callerPackage,
String callerFeatureId, IIntentReceiver receiver, IntentFilter filter,
String permission, int userId, int flags) {
//...
synchronized (this) {
// 根據(jù)IntentReceiver查看緩存中是否有ReceiverList
ReceiverList rl = mRegisteredReceivers.get(receiver.asBinder());
// 創(chuàng)建一個(gè)新的ReceiverList，并把IntentReceiver傳入其中
if (rl == null) {
rl = new ReceiverList(this, callerApp, callingPid, callingUid,
userId, receiver);
mRegisteredReceivers.put(receiver.asBinder(), rl); // 增加到緩存中
}
// 創(chuàng)建一個(gè)BroadcastFilter對(duì)象，并把ReceiverList對(duì)象和IntentFilter對(duì)象傳入其中
BroadcastFilter bf = new BroadcastFilter(filter, rl, callerPackage, callerFeatureId,
permission, callingUid, userId, instantApp, visibleToInstantApps);
// 向ReceiverList對(duì)象增加BroadcastFilter對(duì)象
rl.add(bf);
// 向mReceiverResolver變量增加BroadcastFilter對(duì)象
mReceiverResolver.addFilter(bf);
// ...
return sticky;
}
}
}
在registerReceiverWithFeature方法中省略了很多代碼，主要代碼中就是創(chuàng)建一個(gè)有IntentFilter和IntentReceiver的BroadcastFilter對(duì)象，然后將BroadcastFilter對(duì)象加入到AMS的變量mReceiverResolver中。
廣播的發(fā)送
廣播的發(fā)送是通過(guò)Activity/Service的Context的sendBroadcast、sendOrderedBroadcast方法將Intent發(fā)送廣播:
val intent = Intent(this, MyBroadcastReceiver::class.java)
intent.action = ACTION
sendBroadcast(intent)
Context處理廣播發(fā)送
public class ContextWrapper extends Context {
Context mBase;
@Override
public void sendBroadcast(Intent intent) {
mBase.sendBroadcast(intent);
}
@Override
public void sendBroadcast(Intent intent, String receiverPermission) {
mBase.sendBroadcast(intent, receiverPermission);
}
}
class ContextImpl extends Context {
public void sendBroadcast(Intent intent) {
warnIfCallingFromSystemProcess();
String resolvedType = intent.resolveTypeIfNeeded(getContentResolver());
try {
intent.prepareToLeaveProcess(this);
// 調(diào)用AMS的broadcastIntentWithFeature方法
ActivityManager.getService().broadcastIntentWithFeature(
mMainThread.getApplicationThread(), getAttributionTag(), intent, resolvedType,
null, Activity.RESULT_OK, null, null, null, AppOpsManager.OP_NONE, null, false,
false, getUserId());
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
@Override
public void sendBroadcast(Intent intent, String receiverPermission) {
warnIfCallingFromSystemProcess();
String resolvedType = intent.resolveTypeIfNeeded(getContentResolver());
String[] receiverPermissions = receiverPermission == null ? null
: new String[]{receiverPermission};
try {
intent.prepareToLeaveProcess(this);
ActivityManager.getService().broadcastIntentWithFeature(
mMainThread.getApplicationThread(), getAttributionTag(), intent, resolvedType,
null, Activity.RESULT_OK, null, null, receiverPermissions,
AppOpsManager.OP_NONE, null, false, false, getUserId());
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
}
最后調(diào)用AMS的broadcastIntentWithFeature方法。
AMS處理發(fā)送廣播
我們發(fā)送廣播的類型可分為：無(wú)序廣播(并行)、有序廣播(有序)。對(duì)于動(dòng)態(tài)注冊(cè)的廣播接收器如果接收到的是并行廣播則并行執(zhí)行，如果是串行廣播則串行執(zhí)行。如果是靜態(tài)注冊(cè)的工廣播接收器則無(wú)論發(fā)送的廣播是否為并行還是串行，都按串行執(zhí)行。
public class ActivityManagerService extends IActivityManager.Stub {
public final int broadcastIntentWithFeature(IApplicationThread caller, String callingFeatureId,
Intent intent, String resolvedType, IIntentReceiver resultTo,
int resultCode, String resultData, Bundle resultExtras,
String[] requiredPermissions, int appOp, Bundle bOptions,
boolean serialized, boolean sticky, int userId) {
enforceNotIsolatedCaller("broadcastIntent");
synchronized (this) {
intent = verifyBroadcastLocked(intent);
final ProcessRecord callerApp = getRecordForAppLocked(caller);
final int callingPid = Binder.getCallingPid();
final int callingUid = Binder.getCallingUid();
final long origId = Binder.clearCallingIdentity();
try {
return broadcastIntentLocked(callerApp,
callerApp != null ? callerApp.info.packageName : null, callingFeatureId,
intent, resolvedType, resultTo, resultCode, resultData, resultExtras,
requiredPermissions, appOp, bOptions, serialized, sticky,
callingPid, callingUid, callingUid, callingPid, userId);
} finally {
Binder.restoreCallingIdentity(origId);
}
}
}
@GuardedBy("this")
final int broadcastIntentLocked(ProcessRecord callerApp,
String callerPackage, String callerFeatureId, Intent intent, String
resolvedType,
IIntentReceiver resultTo, int resultCode, String resultData,
Bundle resultExtras, String[] requiredPermissions, int appOp, Bundle bOptions,
boolean ordered, boolean sticky, int callingPid, int callingUid, int realCallingUid,
int realCallingPid, int userId) {
return broadcastIntentLocked(callerApp, callerPackage, callerFeatureId, intent,
resolvedType, resultTo, resultCode, resultData, resultExtras, requiredPermissions,
appOp, bOptions, ordered, sticky, callingPid, callingUid, realCallingUid,
realCallingPid, userId, false /* allowBackgroundActivityStarts */,
null /*broadcastWhitelist*/);
}
@GuardedBy("this")
final int broadcastIntentLocked(ProcessRecord callerApp, String callerPackage,
@Nullable String callerFeatureId, Intent intent, String resolvedType,
IIntentReceiver resultTo, int resultCode, String resultData,
Bundle resultExtras, String[] requiredPermissions, int appOp, Bundle bOptions,
boolean ordered, boolean sticky, int callingPid, int callingUid, int realCallingUid,
int realCallingPid, int userId, boolean allowBackgroundActivityStarts,
@Nullable int[] broadcastWhitelist) {
intent = new Intent(intent);
//增加該flag，則廣播不會(huì)發(fā)送給已停止的package
intent.addFlags(Intent.FLAG_EXCLUDE_STOPPED_PACKAGES);
//...
// ...廣播權(quán)限驗(yàn)證
// ... 處理系統(tǒng)相關(guān)廣播
// ...增加sticky廣播
// 通過(guò)Intent查詢到對(duì)應(yīng)的廣播接收器
List receivers = null; // 靜態(tài)廣播接收器
List<BroadcastFilter> registeredReceivers = null; //動(dòng)態(tài)廣播接收器
//當(dāng)允許靜態(tài)接收者處理該廣播，則通過(guò)PKMS根據(jù)Intent查詢相應(yīng)的靜態(tài)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) {
...
} else {
// 查詢相應(yīng)的動(dòng)態(tài)注冊(cè)的廣播
registeredReceivers = mReceiverResolver.queryIntent(intent,
resolvedType, false, userId);
}
}
int NR = registeredReceivers != null ? registeredReceivers.size() : 0;
// 處理并行廣播，并且只給動(dòng)態(tài)廣播接收器并行處理
if (!ordered && NR > 0) {
// 根據(jù)Intent查詢是前臺(tái)還是后臺(tái)BroadcastQueue
final BroadcastQueue queue = broadcastQueueForIntent(intent);
// 創(chuàng)建一個(gè)BroadcastRecord，參數(shù)有Intent和registeredReceivers
BroadcastRecord r = new BroadcastRecord(queue, intent, callerApp, callerPackage,
callerFeatureId, callingPid, callingUid, callerInstantApp, resolvedType,
requiredPermissions, appOp, brOptions, registeredReceivers, resultTo,
resultCode, resultData, resultExtras, ordered, sticky, false, userId,
allowBackgroundActivityStarts, timeoutExempt);
if (!replaced) {
// 將BroadcastRecord加入到mParallelBroadcasts隊(duì)列
queue.enqueueParallelBroadcastLocked(r);
// 執(zhí)行隊(duì)列
queue.scheduleBroadcastsLocked();
}
// 如果是并行廣播，執(zhí)行完成后動(dòng)態(tài)廣播接收器清空處理
registeredReceivers = null;
NR = 0;
}
//...
//如果此時(shí)registeredReceivers不為null，則表明這是一個(gè)串行廣播
// 則將registeredReceivers合并到receivers一起執(zhí)行串行處理
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) {
receivers.add(it, curr);
ir++;
curr = null;
it++;
NT++;
} else {
it++;
curt = null;
}
}
while (ir < NR) {
if (receivers == null) {
receivers = new ArrayList();
}
receivers.add(registeredReceivers.get(ir));
ir++;
}
// receivers執(zhí)行串行廣播
if ((receivers != null && receivers.size() > 0)
|| resultTo != null) {
//根據(jù)intent的flag來(lái)判斷前臺(tái)隊(duì)列或者后臺(tái)隊(duì)列
BroadcastQueue queue = broadcastQueueForIntent(intent);
//創(chuàng)建BroadcastRecord
BroadcastRecord r = new BroadcastRecord(queue, intent, callerApp,
callerPackage, callingPid, callingUid, resolvedType,
requiredPermissions, appOp, brOptions, receivers, resultTo, resultCode,
resultData, resultExtras, ordered, sticky, false, userId);
boolean replaced = replacePending && queue.replaceOrderedBroadcastLocked(r);
if (!replaced) {
//將BroadcastRecord加入到有序廣播隊(duì)列
queue.enqueueOrderedBroadcastLocked(r);
//處理廣播
queue.scheduleBroadcastsLocked();
}
}
return ActivityManager.BROADCAST_SUCCESS;
}
}
在AMS的broadcastIntentLocked方法中
- 通過(guò)
Intent去PKMS和AMS. mReceiverResolver變量查詢到對(duì)應(yīng)的廣播接收器，其中變量receivers存儲(chǔ)靜態(tài)接收器，registeredReceivers變量存儲(chǔ)動(dòng)態(tài)接收器。 - 如果發(fā)送的是并行廣播，則查看是否有對(duì)應(yīng)的動(dòng)態(tài)廣播接收器，并創(chuàng)建一個(gè)擁有Intent和registeredReceivers的
BroadcastRecord對(duì)象，并保存在BroadcastQueue.mParallelBroadcasts變量中，最終執(zhí)行queue.scheduleBroadcastsLocked()處理廣播，并把registeredReceivers信息置null。 - 如果此時(shí)registeredReceivers不為null，說(shuō)明發(fā)送的是串行廣播，則把registeredReceivers合并到receivers變量，一起串行執(zhí)行。
- 對(duì)receivers進(jìn)行串行執(zhí)行，創(chuàng)建一個(gè)擁有Intent和receivers的
BroadcastRecord對(duì)象，并保存到隊(duì)列的mOrderedBroadcasts變量中，最終執(zhí)行queue.scheduleBroadcastsLocked()處理廣播。
BroadcastQueue處理廣播
public final class BroadcastQueue {
public void scheduleBroadcastsLocked() {
if (mBroadcastsScheduled) {
return;
}
// 發(fā)送BROADCAST_INTENT_MSG類型消息
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) {
// 執(zhí)行此消息
case BROADCAST_INTENT_MSG: {
processNextBroadcast(true);
}
break;
}
}
}
final void processNextBroadcast(boolean fromMsg) {
synchronized (mService) {
processNextBroadcastLocked(fromMsg, false);
}
}
final void processNextBroadcastLocked(boolean fromMsg, boolean skipOomAdj) {
BroadcastRecord r;
//...
//處理并行廣播
while (mParallelBroadcasts.size() > 0) {
//把mParallelBroadcasts隊(duì)列的BroadcastRecord執(zhí)行完
r = mParallelBroadcasts.remove(0);
r.dispatchTime = SystemClock.uptimeMillis();
r.dispatchClockTime = System.currentTimeMillis();
// r.receivers就是AMS的registeredReceivers變量
final int N = r.receivers.size();
for (int i = 0; i < N; i++) {
Object target = r.receivers.get(i);
//分發(fā)廣播給已注冊(cè)的receiver
deliverToRegisteredReceiverLocked(r, (BroadcastFilter) target, false, i);
}
addBroadcastToHistoryLocked(r);
}
// 處理當(dāng)前有序廣播
do {
// 獲取BroadcastRecord
final long now = SystemClock.uptimeMillis();
r = mDispatcher.getNextBroadcastLocked(now);
//沒(méi)有更多的廣播等待處理
if (r == null) {
mDispatcher.scheduleDeferralCheckLocked(false);
mService.scheduleAppGcsLocked();
if (looped) {
mService.updateOomAdjLocked(OomAdjuster.OOM_ADJ_REASON_START_RECEIVER);
}
if (mService.mUserController.mBootCompleted && mLogLatencyMetrics) {
mLogLatencyMetrics = false;
}
return;
}
boolean forceReceive = false;
// 獲取Receivers的大小
int numReceivers = (r.receivers != null) ? r.receivers.size() : 0;
//當(dāng)廣播處理時(shí)間超時(shí)，則強(qiáng)制結(jié)束這條廣播
if (mService.mProcessesReady && !r.timeoutExempt && r.dispatchTime > 0) {
if ((numReceivers > 0) &&
(now > r.dispatchTime + (2 * mConstants.TIMEOUT * numReceivers))) {
broadcastTimeoutLocked(false); // forcibly finish this broadcast
forceReceive = true;
r.state = BroadcastRecord.IDLE;
}
}
//...
if (r.receivers == null || r.nextReceiver >= numReceivers
|| r.resultAbort || forceReceive) {
if (r.resultTo != null) {
//...
//處理廣播消息消息，調(diào)用到onReceive()
performReceiveLocked(r.callerApp, r.resultTo,
new Intent(r.intent), r.resultCode,
r.resultData, r.resultExtras, false, false, r.userId);
//...
}
//...
mDispatcher.retireBroadcastLocked(r);
r = null;
looped = true;
continue;
}
//..
} while (r == null);
//獲取下一個(gè)receiver的index
int recIdx = r.nextReceiver++;
r.receiverTime = SystemClock.uptimeMillis();
if (recIdx == 0) {
r.dispatchTime = r.receiverTime;
r.dispatchClockTime = System.currentTimeMillis();
}
if (!mPendingBroadcastTimeoutMessage) {
long timeoutTime = r.receiverTime + mTimeoutPeriod;
//設(shè)置廣播超時(shí)時(shí)間，發(fā)送BROADCAST_TIMEOUT_MSG
setBroadcastTimeoutLocked(timeoutTime);
}
final BroadcastOptions brOptions = r.options;
//獲取下一個(gè)廣播接收者
final Object nextReceiver = r.receivers.get(recIdx);
if (nextReceiver instanceof BroadcastFilter) {
//對(duì)于動(dòng)態(tài)注冊(cè)的廣播接收者，deliverToRegisteredReceiverLocked處理廣播
BroadcastFilter filter = (BroadcastFilter) nextReceiver;
deliverToRegisteredReceiverLocked(r, filter, r.ordered);
if (r.receiver == null || !r.ordered) {
r.state = BroadcastRecord.IDLE;
scheduleBroadcastsLocked();
} else {
...
}
return;
}
//對(duì)于靜態(tài)注冊(cè)的廣播接收者
ResolveInfo info = (ResolveInfo) nextReceiver;
ComponentName component = new ComponentName(
info.activityInfo.applicationInfo.packageName,
info.activityInfo.name);
...
//執(zhí)行各種權(quán)限檢測(cè)，此處省略，當(dāng)權(quán)限不滿足時(shí)skip=true
if (skip) {
r.receiver = null;
r.curFilter = null;
r.state = BroadcastRecord.IDLE;
scheduleBroadcastsLocked();
return;
}
r.state = BroadcastRecord.APP_RECEIVE;
String targetProcess = info.activityInfo.processName;
r.curComponent = component;
final int receiverUid = info.activityInfo.applicationInfo.uid;
if (r.callingUid != Process.SYSTEM_UID && isSingleton
&& mService.isValidSingletonCall(r.callingUid, receiverUid)) {
info.activityInfo = mService.getActivityInfoForUser(info.activityInfo, 0);
}
r.curReceiver = info.activityInfo;
...
//Broadcast正在執(zhí)行中，stopped狀態(tài)設(shè)置成false
AppGlobals.getPackageManager().setPackageStoppedState(
r.curComponent.getPackageName(), false, UserHandle.getUserId(r.callingUid));
//該receiver所對(duì)應(yīng)的進(jìn)程已經(jīng)運(yùn)行，則直接處理
ProcessRecord app = mService.getProcessRecordLocked(targetProcess,
info.activityInfo.applicationInfo.uid, false);
if (app != null && app.thread != null) {
try {
app.addPackage(info.activityInfo.packageName,
info.activityInfo.applicationInfo.versionCode, mService.mProcessStats);
processCurBroadcastLocked(r, app);
return;
} catch (RemoteException e) {
} catch (RuntimeException e) {
finishReceiverLocked(r, r.resultCode, r.resultData, r.resultExtras, r.resultAbort, false);
scheduleBroadcastsLocked();
r.state = BroadcastRecord.IDLE; //啟動(dòng)receiver失敗則重置狀態(tài)
return;
}
}
//該receiver所對(duì)應(yīng)的進(jìn)程尚未啟動(dòng)，則創(chuàng)建該進(jìn)程
if ((r.curApp=mService.startProcessLocked(targetProcess,
info.activityInfo.applicationInfo, true,
r.intent.getFlags() | Intent.FLAG_FROM_BACKGROUND,
"broadcast", r.curComponent,
(r.intent.getFlags()&Intent.FLAG_RECEIVER_BOOT_UPGRADE) != 0, false, false))
== null) {
//創(chuàng)建失敗，則結(jié)束該receiver
finishReceiverLocked(r, r.resultCode, r.resultData,
r.resultExtras, r.resultAbort, false);
scheduleBroadcastsLocked();
r.state = BroadcastRecord.IDLE;
return;
}
mPendingBroadcast = r;
mPendingBroadcastRecvIndex = recIdx;
//...
}
private void deliverToRegisteredReceiverLocked(BroadcastRecord r,
BroadcastFilter filter, boolean ordered, int index) {
//...
// 調(diào)用performReceiveLocked方法
performReceiveLocked(filter.receiverList.app, filter.receiverList.receiver,
new Intent(r.intent), r.resultCode, r.resultData,
r.resultExtras, r.ordered, r.initialSticky, r.userId);
//...
}
void performReceiveLocked(ProcessRecord app, IIntentReceiver receiver,
Intent intent, int resultCode, String data, Bundle extras,
boolean ordered, boolean sticky, int sendingUser)
throws RemoteException {
if (app != null) {
// 如果ProcessRecord != null，且ApplicationThread不為空
if (app.thread != null) {
try {
// 調(diào)用ApplicationThread.scheduleRegisteredReceiver
app.thread.scheduleRegisteredReceiver(receiver, intent, resultCode,
data, extras, ordered, sticky, sendingUser, app.getReportedProcState());
} catch (RemoteException ex) {
synchronized (mService) {
app.scheduleCrash("can't deliver broadcast");
}
throw ex;
}
} else {
// Application has died. Receiver doesn't exist.
throw new RemoteException("app.thread must not be null");
}
} else {
// 如果ProcessRecord為空
receiver.performReceive(intent, resultCode, data, extras, ordered,
sticky, sendingUser);
}
}
}
BroadcastQueue就是將隊(duì)列中列表拿出來(lái)執(zhí)行，最后調(diào)用app.thread.scheduleRegisteredReceiver對(duì)廣播進(jìn)行回調(diào)。
回調(diào)廣播
private class ApplicationThread extends IApplicationThread.Stub {
public void scheduleRegisteredReceiver(IIntentReceiver receiver, Intent intent,
int resultCode, String dataStr, Bundle extras, boolean ordered,
boolean sticky, int sendingUser, int processState) throws RemoteException {
updateProcessState(processState, false);
// 調(diào)用IntentReceiver的performReceive方法
receiver.performReceive(intent, resultCode, dataStr, extras, ordered,
sticky, sendingUser);
}
}
public final class LoadedApk {
static final class ReceiverDispatcher {
final static class InnerReceiver extends IIntentReceiver.Stub {
final WeakReference<ReceiverDispatcher> mDispatcher;
final LoadedApk.ReceiverDispatcher mStrongRef;
InnerReceiver(LoadedApk.ReceiverDispatcher rd, boolean strong) {
mDispatcher = new WeakReference<LoadedApk.ReceiverDispatcher>(rd);
mStrongRef = strong ? rd : null;
}
@Override
public void performReceive(Intent intent, int resultCode, String data,
Bundle extras, boolean ordered, boolean sticky, int sendingUser) {
final LoadedApk.ReceiverDispatcher rd;
//...
if (rd != null) {
// 調(diào)用ReceiverDispatcher的performReceive方法
rd.performReceive(intent, resultCode, data, extras,
ordered, sticky, sendingUser);
}
//...
}
}
// ReceiverDispatcher的performReceive方法
public void performReceive(Intent intent, int resultCode, String data,
Bundle extras, boolean ordered, boolean sticky, int sendingUser) {
final Args args = new Args(intent, resultCode, data, extras, ordered,
sticky, sendingUser);
//...
// 通過(guò)Handler執(zhí)行args的Runnable
if (intent == null || !mActivityThread.post(args.getRunnable())) {
if (mRegistered && ordered) {
IActivityManager mgr = ActivityManager.getService();
args.sendFinished(mgr);
}
}
}
final class Args extends BroadcastReceiver.PendingResult {
public final Runnable getRunnable() {
return () -> {
final BroadcastReceiver receiver = mReceiver;
//...
try {
ClassLoader cl = mReceiver.getClass().getClassLoader();
intent.setExtrasClassLoader(cl);
intent.prepareToEnterProcess();
setExtrasClassLoader(cl);
receiver.setPendingResult(this);
// 調(diào)用BroadcastReceiver的onReceive方法
receiver.onReceive(mContext, intent);
} catch (Exception e) {
//...
}
if (receiver.getPendingResult() != null) {
finish();
}
};
}
}
}
