产品推广网站哪个好,wordpress显示称谓,网站开发用原生,php网站开发报告书之前看过 Activity 的启动过程#xff0c;也看过 Service 启动过程#xff0c;今天又重新对广播的发送和接收过程做一个源码的了解和查看。 1. registerReceiver MyBroadcastReceiver mBroadcastReceiver new MyBroadcastReceiver();IntentFilter filter new IntentFilter… 之前看过 Activity 的启动过程也看过 Service 启动过程今天又重新对广播的发送和接收过程做一个源码的了解和查看。 1. registerReceiver MyBroadcastReceiver mBroadcastReceiver new MyBroadcastReceiver();IntentFilter filter new IntentFilter();filter.addAction(com.example.qq);registerReceiver(mBroadcastReceiver, filter);我们通常会自定义一个类 MyBroadcastReceiver extends BroadcastReceiver.
跟随 registerReceiver 我们走到第二个步骤
1.1 ContextImpl#registerReceiver
Overridepublic Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter) {return registerReceiver(receiver, filter, null, null);}Overridepublic Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter,String broadcastPermission, Handler scheduler) {return registerReceiverInternal(receiver, getUserId(),filter, broadcastPermission, scheduler, getOuterContext());}最终会执行到 registerReceiverInternal() 这个方法紧接着到第三个步骤
1.2. ContextImpl#registerReceiverInternal
private Intent registerReceiverInternal(BroadcastReceiver receiver, int userId,IntentFilter filter, String broadcastPermission,Handler scheduler, Context context) {IIntentReceiver rd null;//这个IItentReceiver 是一个aidl ,一个Binderif (receiver ! null) {if (mPackageInfo ! null context ! null) {//这个为null, 因为前面我们传的是null,获取主线程的一个handlerif (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 {//这里我们仔细查看这里对比我们平时写的Aidlfinal Intent intent ActivityManagerNative.getDefault().registerReceiver(mMainThread.getApplicationThread(), mBasePackageName,rd, filter, broadcastPermission, userId);if (intent ! null) {intent.setExtrasClassLoader(getClassLoader());intent.prepareToEnterProcess();}return intent;} catch (RemoteException e) {throw e.rethrowFromSystemServer();}}对于
final Intent intent ActivityManagerNative.getDefault().registerReceiver(mMainThread.getApplicationThread(), mBasePackageName,rd, filter, broadcastPermission, userId);ActivityManagerNative.getDefault() 获取到一个 IActivityManager 对象此时我发现我进入一个类名为 ActivityManagerNative 的一个类中。
这里补充 IActivityManager ,它是一个 aidl 文件如下
public interface IActivityManager extends IInterface {....
}这时让我想起我们以前写 aidl 的示例时系统自动帮我们生成的文件下面我们来对比一下可以加深对 aidl 的理解
自动生成的aidl文件 我们创建一个 IMyAidl.aidl 文件,编译系统会自动生成大致如下
public interface IMyAidl extends android.os.IInterface{public static abstract class Stub extends android.os.Binder implements xx.IMyAidl{public Stub(){this.attachInterface(this, DESCRIPTOR);}public static com.example.service.bean.IMyAidl asInterface(android.os.IBinder obj) {xxx...return new com.example.service.bean.IMyAidl.Stub.Proxy(obj);}Overridepublic boolean onTransact(int code, android.os.Parcel data, android.os.Parcel reply, int flags) throws android.os.RemoteException {case TRANSACTION_addPerson: {//其中一个方法data.enforceInterface(DESCRIPTOR);com.example.service.bean.Person _arg0;if ((0 ! data.readInt())) {_arg0 com.example.service.bean.Person.CREATOR.createFromParcel(data);} else {_arg0 null;}this.addPerson(_arg0);reply.writeNoException();return true;}}}private static class Proxy implements xx.IMyAidl {private android.os.IBinder mRemote;Proxy(android.os.IBinder remote) {mRemote remote;}Overridepublic void addPerson(com.example.service.bean.Person person) throws android.os.RemoteException {android.os.Parcel _data android.os.Parcel.obtain();android.os.Parcel _reply android.os.Parcel.obtain();try {_data.writeInterfaceToken(DESCRIPTOR);if ((person ! null)) {_data.writeInt(1);person.writeToParcel(_data, 0);} else {_data.writeInt(0);}//调用远程binder,transactmRemote.transact(Stub.TRANSACTION_addPerson, _data, _reply, 0);_reply.readException();} finally {_reply.recycle();_data.recycle();}}}static final int TRANSACTION_addPerson (android.os.IBinder.FIRST_CALL_TRANSACTION 0);
}其中我们最主要关心的是 Stub 和 Proxy .那么类比下 ActivityManagerNative 类(我简化了一下)
public abstract class ActivityManagerNative extends Binder implements IActivityManager{class ActivityManagerProxy implements IActivityManager{public ActivityManagerProxy(IBinder remote) {mRemote remote;}}
}你会发现这与系统帮我们自动生成文件的结构有异曲同工之处那么在这里
ActivityManagerNative ------ 对应的就是 Stub
ActivityManagerProxy ------- 对应的就是 Proxy
那么真正实现 ActivityManagerNative 又是谁呢其实就是 ActivityManagerService , 可看到
public final class ActivityManagerService extends ActivityManagerNative ...{...
}这样的话我们回到之前的那个步骤
final Intent intent ActivityManagerNative.getDefault().registerReceiver(mMainThread.getApplicationThread(), mBasePackageName,rd, filter, broadcastPermission, userId);这里我们就知道了 这里调用 ActivityManagerNative.getDefault().registerReceiver 其实就是调用 ActivityManagerService.registerReceiver() 方法。 还有一个补充的是 mMainThread.getApplicationThread() 实际上对应的是 ApplicationThread 1.3 ActivityManagerService#registerReceiver
这个方法有点长不过没关系分块看就行
public Intent registerReceiver(IApplicationThread caller, String callerPackage,IIntentReceiver receiver, IntentFilter filter, String permission, int userId) {enforceNotIsolatedCaller(registerReceiver);ArrayListIntent stickyIntents null;ProcessRecord callerApp null;int callingUid;int callingPid;synchronized(this) {//这个肯定不为nullif (caller ! null) {//表示启动app的进程信息保存在ProcessRecord类型的对象中callerApp getRecordForAppLocked(caller);if (callerApp null) {throw new SecurityException(Unable to find app for caller caller (pid Binder.getCallingPid() ) when registering receiver receiver);}....} else {...}userId mUserController.handleIncomingUser(callingPid, callingUid, userId, true,ALLOW_FULL_ONLY, registerReceiver, callerPackage);.... // Collect stickies of usersint[] userIds { UserHandle.USER_ALL, UserHandle.getUserId(callingUid) };//遍历 action while (actions.hasNext()) {String action actions.next();for (int id : userIds) {ArrayMapString, ArrayListIntent stickies mStickyBroadcasts.get(id);if (stickies ! null) {ArrayListIntent intents stickies.get(action);if (intents ! null) {if (stickyIntents null) {stickyIntents new ArrayListIntent();}stickyIntents.addAll(intents);}}}}}ArrayListIntent 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 ArrayListIntent();}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) {...//获取接收者的一个集合 ReceiverListReceiverList 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);} ...//IntentFilter 相关的BroadcastFilter bf new BroadcastFilter(filter, rl, callerPackage,permission, callingUid, userId);rl.add(bf);if (!bf.debugCheck()) {Slog.w(TAG, For Dynamic broadcast);}//最后添加到了mReceiverResolver 中最后发送广播也是从这里面去取///**//* Keeps track of all IIntentReceivers that have been registered for broadcasts.// * Hash keys are the receiver IBinder, hash value is a ReceiverList.//*///final HashMapIBinder, ReceiverList mRegisteredReceivers new HashMap();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);//得到一个接收此广播的队列 BroadcastQueueBroadcastQueue queue broadcastQueueForIntent(intent);//广播的信息封装在一个BroadcastRecord 对象中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);// 这里可以认为是一个入队操作就像Handler 中的 Message中一样 queue.enqueueParallelBroadcastLocked(r);//调用 scheduleBroadcastsLockedqueue. scheduleBroadcastsLocked();}}return sticky;}}2. sendBoradcastReceiver Intent intent new Intent();intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);intent.setAction(com.example.qq);sendBroadcast(intent);2.1 ContextImpl#sendBroadcast
Overridepublic void sendBroadcast(Intent intent) {warnIfCallingFromSystemProcess();String resolvedType intent.resolveTypeIfNeeded(getContentResolver());try {intent.prepareToLeaveProcess(this);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 e.rethrowFromSystemServer();}}这里我们就知道 ActivityManagerNative.getDefault() 实际上可以认为是 ActivityManagerService 调用 broadcastIntent 方法。
2.2 ActivityManagerService#broadcastIntent public final int broadcastIntent(IApplicationThread caller,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();//到这里int res broadcastIntentLocked(callerApp,callerApp ! null ? callerApp.info.packageName : null,intent, resolvedType, resultTo, resultCode, resultData, resultExtras,requiredPermissions, appOp, bOptions, serialized, sticky,callingPid, callingUid, userId);Binder.restoreCallingIdentity(origId);return res;}}2.3 ActivityManagerService#broadcastIntentLocked
这个里面方法挺长的
....
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();}....2.4 BroadcastQueue#scheduleBroadcastsLocked
public void scheduleBroadcastsLocked() {if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, Schedule broadcasts [ mQueueName ]: current mBroadcastsScheduled);if (mBroadcastsScheduled) {return;}//这里发送了一条消息mHandler.sendMessage(mHandler.obtainMessage(BROADCAST_INTENT_MSG, this));mBroadcastsScheduled true;}private final class BroadcastHandler extends Handler {public BroadcastHandler(Looper looper) {super(looper, null, true);}Overridepublic void handleMessage(Message msg) {switch (msg.what) {case BROADCAST_INTENT_MSG: {if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, Received BROADCAST_INTENT_MSG);processNextBroadcast(true);} break;...2.5 BroadcastQueue#processNextBroadcast
这个方法也比较长挑一些重点的看下
final void processNextBroadcast(boolean fromMsg) {...// First, deliver any non-serialized broadcasts right away.//这个表示对无序广播的处理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_BROADCAST, Processing parallel broadcast [ mQueueName ] r);for (int i0; iN; i) {//取出一个接收者targetObject target r.receivers.get(i);if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,Delivering non-ordered on [ mQueueName ] to registered target : r);//又调用 deliverToRegisteredReceiverLocked deliverToRegisteredReceiverLocked(r, (BroadcastFilter)target, false, i);}addBroadcastToHistoryLocked(r);if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG_BROADCAST, Done with parallel broadcast [ mQueueName ] r);}
}2.6 BroadcastQueue#deliverToRegisteredReceiverLocked private void deliverToRegisteredReceiverLocked(BroadcastRecord r,BroadcastFilter filter, boolean ordered, int index) {//根据上面所传的ordered 为false 表示无序广播....if (ordered) {//这个表示有序广播r.receiver filter.receiverList.receiver.asBinder();r.curFilter filter;filter.receiverList.curBroadcast r;r.state BroadcastRecord.CALL_IN_RECEIVE;if (filter.receiverList.app ! null) {// Bump hosting application to no longer be in background// scheduling class. Note that we cant do that if there// isnt an app... but we can only be in that case for// things that directly call the IActivityManager API, which// are already core system stuff so dont matter for this.r.curApp filter.receiverList.app;filter.receiverList.app.curReceiver r;mService.updateOomAdjLocked(r.curApp);}}try {//关于isFullBackup Process is currently hosting a backup agent for backup or restore//public boolean inFullBackup;默认是falseif (filter.receiverList.app ! null filter.receiverList.app.inFullBackup) {// Skip delivery if full backup in progress// If its an ordered broadcast, we need to continue to the next receiver.if (ordered) {skipReceiverLocked(r);}} else {//到这里performReceiveLocked(filter.receiverList.app, filter.receiverList.receiver,new Intent(r.intent), r.resultCode, r.resultData,r.resultExtras, r.ordered, r.initialSticky, r.userId);}if (ordered) {r.state BroadcastRecord.CALL_DONE_RECEIVE;}} catch (RemoteException e) {....}2.7 BroadcastQueue#performReceiveLocked
void performReceiveLocked(ProcessRecord app, IIntentReceiver receiver,Intent intent, int resultCode, String data, Bundle extras,boolean ordered, boolean sticky, int sendingUser) throws RemoteException {// Send the intent to the receiver asynchronously using one-way binder calls.....if (app ! null) {if (app.thread ! null) {app.thread.scheduleRegisteredReceiver(receiver, intent, resultCode,data, extras, ordered, sticky, sendingUser, app.repProcState);}.... }app.thread 是 ApplicationThread , 此时回归到了客户端进程ApplicationThread 中了
2.8 ApplicationThread#scheduleRegisteredReceiver
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);receiver.performReceive(intent, resultCode, dataStr, extras, ordered,sticky, sendingUser);}这里调用了 IIntentReceiver#performReceive 方法, 其中 IIntentReceiver 是一个 aidl 如下 /framworkds/base/core/java/android/content/IIntentReceiver.aidl
/*** System private API for dispatching intent broadcasts. This is given to the* activity manager as part of registering for an intent broadcasts, and is* called when it receives intents.** {hide}*/
oneway interface IIntentReceiver {void performReceive(in Intent intent, int resultCode,String data, in Bundle extras, boolean ordered, boolean sticky);
}既然是 aidl 肯定有最终实现者全局搜索发现
InnerReceiver 是最终实现者是ReceiverDispatcher 的一个静态内部类在 LoadedApk.java 文件中
LoadedApk#ReceiverDispatcher
static final class ReceiverDispatcher {final static class InnerReceiver extends IIntentReceiver.Stub {final WeakReferenceLoadedApk.ReceiverDispatcher mDispatcher;final LoadedApk.ReceiverDispatcher mStrongRef;InnerReceiver(LoadedApk.ReceiverDispatcher rd, boolean strong) {mDispatcher new WeakReferenceLoadedApk.ReceiverDispatcher(rd);mStrongRef strong ? rd : null;}//这里是最终执行的方法 performReceiveOverridepublic void performReceive(Intent intent, int resultCode, String data,Bundle extras, boolean ordered, boolean sticky, int sendingUser) {final LoadedApk.ReceiverDispatcher rd;if (intent null) {Log.wtf(TAG, Null intent received);rd null;} else {rd mDispatcher.get();}...if (rd ! null) {//不为null 执行到这里 rd.performReceive(intent, resultCode, data, extras,ordered, sticky, sendingUser);} else {// The activity manager dispatched a broadcast to a registered// receiver in this process, but before it could be delivered the// receiver was unregistered. Acknowledge the broadcast on its// behalf so that the systems broadcast sequence can continue.if (ActivityThread.DEBUG_BROADCAST) Slog.i(ActivityThread.TAG,Finishing broadcast to unregistered receiver);IActivityManager mgr ActivityManagerNative.getDefault();try {if (extras ! null) {extras.setAllowFds(false);}mgr.finishReceiver(this, resultCode, data, extras, false, intent.getFlags());} catch (RemoteException e) {throw e.rethrowFromSystemServer();}}}}
2.9 ReceiverDispatcher#performReceive
public void performReceive(Intent intent, int resultCode, String data,Bundle extras, boolean ordered, boolean sticky, int sendingUser) {//将信息封装到Args 中final Args args new Args(intent, resultCode, data, extras, ordered,sticky, sendingUser);if (intent null) {Log.wtf(TAG, Null intent received);} else {if (ActivityThread.DEBUG_BROADCAST) {int seq intent.getIntExtra(seq, -1);Slog.i(ActivityThread.TAG, Enqueueing broadcast intent.getAction() seq seq to mReceiver);}}//这里 IActivityThread 一个Handler 类型。post了一条runnableif (intent null || !mActivityThread.post(args)) {if (mRegistered ordered) {IActivityManager mgr ActivityManagerNative.getDefault();if (ActivityThread.DEBUG_BROADCAST) Slog.i(ActivityThread.TAG,Finishing sync broadcast to mReceiver);args.sendFinished(mgr);}}}这里补充下 mActivityThread 赋值是在构造方法中赋值的
ReceiverDispatcher(BroadcastReceiver receiver, Context context,Handler activityThread, Instrumentation instrumentation,boolean registered) {...mIIntentReceiver new InnerReceiver(this, !registered);.... 这里也能猜到 是ActivityThread 中的那个HmActivityThread activityThread;...}这里就可以看 Args ,一个 Runnable, 看下 run 方法
final class Args extends BroadcastReceiver.PendingResult implements Runnable {public void run() {final BroadcastReceiver receiver mReceiver;final boolean ordered mOrdered;if (ActivityThread.DEBUG_BROADCAST) {int seq mCurIntent.getIntExtra(seq, -1);Slog.i(ActivityThread.TAG, Dispatching broadcast mCurIntent.getAction() seq seq to mReceiver);Slog.i(ActivityThread.TAG, mRegistered mRegistered mOrderedHint ordered);}final IActivityManager mgr ActivityManagerNative.getDefault();final Intent intent mCurIntent;if (intent null) {Log.wtf(TAG, Null intent being dispatched, mDispatched mDispatched);}mCurIntent null;mDispatched true;...Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, broadcastReceiveReg);try {//获取receiver的类加载类加载ClassLoader cl mReceiver.getClass().getClassLoader();intent.setExtrasClassLoader(cl);intent.prepareToEnterProcess();setExtrasClassLoader(cl);receiver.setPendingResult(this);//这里回调receiver 的onReceive 方法receiver.onReceive(mContext, intent);} catch (Exception e) {...}...Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);}}这样我们就可以在 sendBroadcast 时在 Receiver 方法中收到相应的回调了完毕。
