startActivity启动流程
第一个阶段
从activity到AMS
Activity.startActivity
startActivityForResult
Instrumentation.execStartActivity//返回值去检测是否注册
ActivityTaskManager.getService().startActivity()//#1 sdk 30 通过获取ActivityTaskManagerService的代理
ActivityManager.getService().startActivity();//sdk28 通过获取AMS的代理
//#1
public static IActivityTaskManager getService() {
return IActivityTaskManagerSingleton.get();
}
private static final Singleton<IActivityTaskManager> IActivityTaskManagerSingleton =
new Singleton<IActivityTaskManager>() {
@Override
protected IActivityTaskManager create() {
final IBinder b = ServiceManager.getService(Context.ACTIVITY_TASK_SERVICE);//通过sm去获取binder
return IActivityTaskManager.Stub.asInterface(b);
}
};
第二个阶段
从AMS到ApplicationThread
AMS.startActivity()
ActivityTaskManagerService.startActivity()//
startActivityAsUser()//添加一个UserHandle.getCallingUserId()
startActivityAsUser()//取出tagetUserId
getActivityStartController().obtainStarter(intent, "startActivityAsUser")//ActivityStartController 在AMS初始化的时候初始化的对象，返回ActivityStarter对象
.setCaller(caller)
.setCallingPackage(callingPackage)
.setCallingFeatureId(callingFeatureId)
.setResolvedType(resolvedType)
.setResultTo(resultTo)
.setResultWho(resultWho)
.setRequestCode(requestCode)
.setStartFlags(startFlags)
.setProfilerInfo(profilerInfo)
.setActivityOptions(bOptions)
.setUserId(userId)
.execute();//ActivityStarter.execute()
executeRequest()//这以后是android30的代码，和以前的有出入，这个方法里面会检查Activity权限等。
startActivityUnchecked()
startActivityInner()//setInitialState()acitivity的启动模式等，computeLaunchingTaskFlags启动栈
RootWindowContainer.resumeFocusedStacksTopActivities()
resumeTopActivityInnerLocked()
ActivityStackSupervisor.startSpecificActivity()//#2
realStartActivityLocked() //ClientLifecycleManager获取到IApplicationThread的代理
ClientLifecycleManager.scheduleTransaction(clientTransaction);
//clientTransaction.clientTransaction.addCallback(LaunchActivityItem.obtain())//这里需要记住//#3
transaction.schedule();//final IApplicationThread client = transaction.getClient();
IApplicationThread.scheduleTransaction()//IApplicationThread是ApplicationThread的代理
ApplicationThread.scheduleTransaction()
ActivityThread.scheduleTransaction()
mH.sendMessage(ActivityThread.H.EXECUTE_TRANSACTION, transaction);
TransactionExecutor.execute()
executeCallbacks(ClientTransaction transaction)
item.execute(mTransactionHandler, token, mPendingActions);//#3 item==LaunchActivityItem
client.handleLaunchActivity(r, pendingActions, null /* customIntent */);
//client == ClientTransactionHandler -> ActivityThread extends ClientTransactionHandler
ActivityThread.performLaunchActivity()
mInstrumentation.newActivity()
Application app = r.packageInfo.makeApplication(false, mInstrumentation);
//#2 ActivityStackSupervisor
void startSpecificActivity(ActivityRecord r, boolean andResume, boolean checkConfig) {
// Is this activity's application already running? 判断app是否是运行的
final WindowProcessController wpc =
mService.getProcessController(r.processName, r.info.applicationInfo.uid);
boolean knownToBeDead = false;
if (wpc != null && wpc.hasThread()) {
try {
realStartActivityLocked(r, wpc, andResume, checkConfig);
return;
} catch (RemoteException e) {
Slog.w(TAG, "Exception when starting activity "
+ r.intent.getComponent().flattenToShortString(), e);
}
knownToBeDead = true;
}
r.notifyUnknownVisibilityLaunchedForKeyguardTransition();
final boolean isTop = andResume && r.isTopRunningActivity();
//冷启动
mService.startProcessAsync(r, knownToBeDead, isTop, isTop ? "top-activity" : "activity");
// skd 29
// mService.startProcessLocked(r.processName, r.info.applicationInfo, true, 0,
// "activity", r.intent.getComponent(), false, false, true);
}
冷启动 skd 30
mService.startProcessAsync(r, knownToBeDead, isTop, isTop ? "top-activity" : "activity");
Message m = PooledLambda.obtainMessage(ActivityManagerInternal::startProcess,//这个方法重要
mAmInternal, activity.processName, activity.info.applicationInfo, knownToBeDead,
isTop, hostingType, activity.intent.getComponent());
mH.sendMessage(m);
ActivityManagerInternal::startProcess//ActivityManagerInternal的是实现类是AMS中的LocalService
startProcessLocked()
mProcessList.startProcessLocked()
startProcess()
Process.start()
ZygoteProcess.start()
startViaZygote()
zygoteSendArgsAndGetResult(openZygoteSocketIfNeeded(abi), zygotePolicyFlags,argsForZygote)
//以下是sendMessage的流程
AppTimeTracker.deliverResult(mContext);
PendingIntent.send(context, 0, fillinIntent);
sendAndReturnResult
ActivityManager.getService().sendIntentSender()//AMS
target.sendWithResult();//target == PendingIntentRecord
sendInner()
ActivityTaskManagerInternal.startActivityInPackage()// LocalService extentds ActivityTaskManagerInternal //ActivityTaskManagerService中
ActivityStartController.startActivityInPackage()
return obtainStarter(intent, reason)
.setCallingUid(uid)
.setRealCallingPid(realCallingPid)
.setRealCallingUid(realCallingUid)
.setCallingPackage(callingPackage)
.setCallingFeatureId(callingFeatureId)
.setResolvedType(resolvedType)
.setResultTo(resultTo)
.setResultWho(resultWho)
.setRequestCode(requestCode)
.setStartFlags(startFlags)
.setActivityOptions(options)
.setUserId(userId)
.setInTask(inTask)
.setOriginatingPendingIntent(originatingPendingIntent)
.setAllowBackgroundActivityStart(allowBackgroundActivityStart)
.execute();
冷启动 sdk 29
mService.startProcessLocked(r, knownToBeDead, isTop, isTop ? "top-activity" : "activity");
AMS.startProcessLocked()很多次之后
startProcess()
Process.start()
zygoteProcess.start()
startViaZygote()
openZygoteSocketIfNeeded//进行socket链接
zygoteSendArgsAndGetResult(openZygoteSocketIfNeeded(abi), argsForZygote)//阻塞//socket通信
startActivity
AMS和APP持有对方的代理
