动态注册registerReceiver:主要就是将广播接收器receiver封装到LoadedApk的InnerReceiver（继承IIntentReceiver接口的binder对象）及广播类型filter传给ActivityManagerService保存起来，别人在发送广播时，在AMS过滤后发送过来.
时序图：
类图可以参考一张图看懂bindService源码流程（包括进程内和新进程）
Step1:注册广播代码
public class TestReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
}
}
IntentFilter filter = new IntentFilter("cn.umbrella.chanage");
registerReceiver(new TestReceiver(), filter);
Step2:ContextImpl.registerReceiver():
class ContextImpl extends Context {
@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 registerReceiverAsUser(BroadcastReceiver receiver, UserHandle user,
IntentFilter filter, String broadcastPermission, Handler scheduler) {
return registerReceiverInternal(receiver, user.getIdentifier(),
filter, broadcastPermission, scheduler, getOuterContext());
}
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 {
final 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();
}
}
}
getOuterContext()就是XXXActivity.
Setp3:scheduler = mMainThread.getHandler()是handler：
public final class ActivityThread {
private class H extends Handler {
}
final Handler getHandler() {
return mH;
}
}
Step 4:LoadedApk.getReceiverDispatcher，返回IIntentReceiver接口对象rd的Binder对象:
public final class LoadedApk {
public IIntentReceiver getReceiverDispatcher(BroadcastReceiver r,
Context context, Handler handler,
Instrumentation instrumentation, boolean registered) {
synchronized (mReceivers) {
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;
return rd.getIIntentReceiver();
}
}
}
从LoadedApk的成员变量mReceivers获取相应的ReceiverDispatcher，如果不存在则新建一个,并保存起来。
Step5:LoadedApk .ReceiverDispatcher :
public final class LoadedApk {
static final class ReceiverDispatcher {
final static class InnerReceiver extends IIntentReceiver.Stub {
final WeakReference<LoadedApk.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;
...
}
}
ReceiverDispatcher(BroadcastReceiver receiver, Context context,
Handler activityThread, Instrumentation instrumentation,
boolean registered) {
...
mIIntentReceiver = new InnerReceiver(this, !registered);
mReceiver = receiver;
mContext = context;
mActivityThread = activityThread;
mInstrumentation = instrumentation;
mRegistered = registered;
mLocation = new IntentReceiverLeaked(null);
mLocation.fillInStackTrace();
}
IIntentReceiver getIIntentReceiver() {
return mIIntentReceiver;
}
}
}
新建ReceiverDispatcher同时,会创建一个实现IIntentReceiver接口的binder对象:InnerReceiver,这是用来和AMS通讯时调用performReceive
Step6:ActivityManagerProxy .registerReceiver
class ActivityManagerProxy implements IActivityManager{
public Intent registerReceiver(IApplicationThread caller, String packageName,
IIntentReceiver receiver,
IntentFilter filter, String perm, int userId) throws RemoteException
{
Parcel data = Parcel.obtain();
Parcel reply = Parcel.obtain();
data.writeInterfaceToken(IActivityManager.descriptor);
data.writeStrongBinder(caller != null ? caller.asBinder() : null);
data.writeString(packageName);
data.writeStrongBinder(receiver != null ? receiver.asBinder() : null);
filter.writeToParcel(data, 0);
data.writeString(perm);
data.writeInt(userId);
mRemote.transact(REGISTER_RECEIVER_TRANSACTION, data, reply, 0);
reply.readException();
Intent intent = null;
int haveIntent = reply.readInt();
if (haveIntent != 0) {
intent = Intent.CREATOR.createFromParcel(reply);
}
reply.recycle();
data.recycle();
return intent;
}
}
这个函数通过Binder驱动程序就进入到ActivityManagerService中的registerReceiver函数中去了。
Step 7:AMS.registerReceiver:
public final class ActivityManagerService extends ActivityManagerNative
implements Watchdog.Monitor, BatteryStatsImpl.BatteryCallback {
public Intent registerReceiver(IApplicationThread caller, String callerPackage,
IIntentReceiver receiver, IntentFilter filter, String permission, int userId) {
enforceNotIsolatedCaller("registerReceiver");
...
synchronized (this) {
...
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);
}
...
mRegisteredReceivers.put(receiver.asBinder(), rl);
}
...
BroadcastFilter bf = new BroadcastFilter(filter, rl, callerPackage,
permission, callingUid, userId);
rl.add(bf);
mReceiverResolver.addFilter(bf);
...
return sticky;
}
}
}
把广播接收器receiver和filter关联起来，并保存到mReceiverResolver.这样，广播接收器注册到这边就可以了。
