一.ActivityManagerService
1.概述
???????AMS是Android系統(tǒng)中一個特別重要的系統(tǒng)服務，也是上層APP打交道最多的系統(tǒng)服務之一，主要負責系統(tǒng)中四大組件的啟動、切換、調度及應用進程的管理和調度等工作，其職責與操作系統(tǒng)中的進程管理和調度模塊相類似，因此它在Android系統(tǒng)中非常重要。
2.組成
2.1.Client
???????由ActivityManager封裝一部分服務接口供Client調用，ActivityManager內部通過調用getService()可以獲取到IActivityManager對象的引用，進而通過該引用遠程服務的方法；
2.2.Server
???????由ActivityManagerService實現(xiàn)，提供Server端的系統(tǒng)服務；
3.啟動過程
???????AMS是在SystemServer中被添加的，本文基于Android 8.1進行分析，先到SystemServer中查看初始化過程：
3.1.SystemServer
public static void main(String[] args) {
new SystemServer().run();
}
???????在run()方法中，創(chuàng)建SystemServiceManager對象，然后啟動一些service。
private void run() {
......
......
// Prepare the main looper thread (this thread).
android.os.Process.setThreadPriority(
android.os.Process.THREAD_PRIORITY_FOREGROUND);
android.os.Process.setCanSelfBackground(false);
Looper.prepareMainLooper();
// Initialize native services.
System.loadLibrary("android_servers");
// Initialize the system context.
createSystemContext();
// Create the system service manager.
mSystemServiceManager = new SystemServiceManager(mSystemContext);
mSystemServiceManager.setRuntimeRestarted(mRuntimeRestart);
LocalServices.addService(SystemServiceManager.class, mSystemServiceManager);
.......
// Start services.
try {
traceBeginAndSlog("StartServices");
startBootstrapServices();
startCoreServices();
startOtherServices();
SystemServerInitThreadPool.shutdown();
}
// Loop forever.
Looper.loop();
}
???????ActivityManagerService是在startBootstrapServices()中創(chuàng)建啟動的。
private void startBootstrapServices() {
......
......
// Activity manager runs the show.
traceBeginAndSlog("StartActivityManager");
mActivityManagerService = mSystemServiceManager.startService(
ActivityManagerService.Lifecycle.class).getService();
mActivityManagerService.setSystemServiceManager(mSystemServiceManager);
mActivityManagerService.setInstaller(installer);
traceEnd();
......
......
// Set up the Application instance for the system process and get started.
traceBeginAndSlog("SetSystemProcess");
//將自己注冊到ServiceManager中，供IPC調用
mActivityManagerService.setSystemProcess();
traceEnd();
.......
}
???????AMS是通過SystemServiceManager.startService去啟動的,參數是ActivityManagerService.Lifecycle.class, 首先看看SystemServiceManager.java的startService方法調用邏輯：
public SystemService startService(String className) {
final Class<SystemService> serviceClass;
try {
serviceClass = (Class<SystemService>)Class.forName(className);
} catch (ClassNotFoundException ex) {
......
}
return startService(serviceClass);
}
???????通過傳入的類名字獲取到對應的class，接著將該class作為參數傳入執(zhí)行下一個startService()方法：
public <T extends SystemService> T startService(Class<T> serviceClass) {
try {
final String name = serviceClass.getName();
......
final T service;
try {
Constructor<T> constructor = serviceClass.getConstructor(Context.class);
service = constructor.newInstance(mContext);
}
......
startService(service);
return service;
}
......
}
???????通過反射獲取到類的構造方法，然后通過newInstance()來創(chuàng)建實例，接著將該實例作為參數傳入執(zhí)行下一個startService()方法：
public void startService(@NonNull final SystemService service) {
// Register it.
mServices.add(service);
// Start it.
long time = SystemClock.elapsedRealtime();
try {
service.onStart();
}
......
}
???????startService方法很簡單，是通過傳進來的class然后反射創(chuàng)建對應的service服務。所以此處創(chuàng)建的是Lifecycle的實例，然后在startService中執(zhí)行了service.onStart()。
???????上面創(chuàng)建ActivityManagerService時傳入的是ActivityManagerService.Lifecycle.class，看一下這個類：
public static final class Lifecycle extends SystemService {
private final ActivityManagerService mService;
public Lifecycle(Context context) {
super(context);
mService = new ActivityManagerService(context);
}
@Override
public void onStart() {
mService.start();
}
@Override
public void onCleanupUser(int userId) {
mService.mBatteryStatsService.onCleanupUser(userId);
}
public ActivityManagerService getService() {
return mService;
}
}
???????通過以上類可以看到，LifeCycle繼承SystemService[SystemService是一個抽象類]，在構造方法中創(chuàng)建了ActivityManagerService對象mService，然后通過getService()可以獲取到mService。
3.2.構造方法
???????看一下ActivityManagerService初始化主要做了什么：
public ActivityManagerService(Context systemContext) {
......
mServices = new ActiveServices(this);
......
mStackSupervisor = createStackSupervisor();
mTaskChangeNotificationController =
new TaskChangeNotificationController(this, mStackSupervisor, mHandler);
mActivityStarter = new ActivityStarter(this, mStackSupervisor);
mRecentTasks = new RecentTasks(this, mStackSupervisor);
mProcessCpuThread = new Thread("CpuTracker") {
@Override
public void run() {
................
................
};
Watchdog.getInstance().addMonitor(this);
Watchdog.getInstance().addThread(mHandler);
}
???????在構造方法中執(zhí)行了許多初始化工作，主要如下：
???????1.創(chuàng)建ActiveServices實例，來處理Service啟動等相關邏輯；
???????2.創(chuàng)建ActivityStackSupervisor實例，核心類，管理ActivityStack，創(chuàng)建ActivityDisplay等；
???????3.創(chuàng)建mTaskChangeNotificationController來監(jiān)聽Task棧變化并進行通知；
???????4.創(chuàng)建ActivityStarter實例，來處理Activity啟動等相關邏輯；
???????5.創(chuàng)建RecentTasks實例，來管理最近打開的任務；
???????6.啟動一個線程專門跟進cpu當前狀態(tài)信息,AMS對當前cpu狀態(tài)了如指掌,可以更加高效的安排其他工作
???????7.注冊看門狗監(jiān)聽進程，每分鐘調用一次監(jiān)視器，如果進程沒有任何返回就殺掉；
3.3.setSystemProcess()
???????前面分析到，在SystemServer中會先啟動ActivityManagerService，啟動完成后會執(zhí)行setSystemProcess()，看一下setSystemProcess()做了什么工作：
public class ActivityManagerService extends IActivityManager.Stub implements xxx {
.......
.......
public void setSystemProcess() {
try {
ServiceManager.addService(Context.ACTIVITY_SERVICE, this, true);
}
......
.......
}
.......
.......
}
???????在setSystemProcess()內部進行服務注冊，首先將ActivityManagerService注冊到ServiceManager中，其次將幾個與系統(tǒng)性能調試相關的服務注冊到ServiceManager。此時其他進程可以通過ServiceManager.getService(Context.ACTIVITY_SERVICE)獲取到IBinder，IActivityManager.Stub.asInterface(IBinder)可以獲取到ActivityManagerService，然后可以與ActivityManagerService進行IPC了。
???????前面講到在SystemServer的main()中會執(zhí)行一系列啟動services，如下：
// Start services.
try {
traceBeginAndSlog("StartServices");
startBootstrapServices();
startCoreServices();
startOtherServices();
SystemServerInitThreadPool.shutdown();
}
???????在startBootstrapServices()中會啟動ActivityManagerService，然后在startOtherServices()中會執(zhí)行到以下邏輯：
mActivityManagerService.systemReady(() -> {
Slog.i(TAG, "Making services ready");
......
......
if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_AUTOMOTIVE)) {
traceBeginAndSlog("StartCarServiceHelperService");
mSystemServiceManager.startService(CarServiceHelperService.class);
traceEnd();
}
traceBeginAndSlog("StartSystemUI");
try {
startSystemUi(context, windowManagerF);
}
.......
.......
}, BOOT_TIMINGS_TRACE_LOG);
static final void startSystemUi(Context context, WindowManagerService windowManager) {
Intent intent = new Intent();
intent.setComponent(new ComponentName("com.android.systemui",
"com.android.systemui.SystemUIService"));
intent.addFlags(Intent.FLAG_DEBUG_TRIAGED_MISSING);
context.startServiceAsUser(intent, UserHandle.SYSTEM);
windowManager.onSystemUiStarted();
}
???????通過以上可以看到，會執(zhí)行到ActivityManagerService的systemReady()方法，然后啟動CarServiceHelperService，接下來會啟動SystemUISerivce，找到了啟動SystemUISerivce的地方，接下來分析一下ActivityManagerService的systemReady()內部主要做了什么工作：
3.4.systemReady()
public void systemReady(final Runnable goingCallback, TimingsTraceLog traceLog) {
traceLog.traceBegin("PhaseActivityManagerReady");
synchronized(this) {
if (mSystemReady) {
if (goingCallback != null) {
goingCallback.run();
}
return;
}
.......
mSystemReady = true;
}
.......
.......
if (goingCallback != null) goingCallback.run();
.......
synchronized (this) {
startPersistentApps(PackageManager.MATCH_DIRECT_BOOT_AWARE);
.......
startHomeActivityLocked(currentUserId, "systemReady");
.......
}
}
}
???????通過以上可以看到，在systemReady()中，有兩處比較重要的地方是：
???????1.執(zhí)行startPersistentApps()，啟動那些在AndroidManifest.xml中設置了android:persist="true"的app。
???????2.執(zhí)行startHomeActivityLocked()，啟動home activity，比如手機端應該是啟動了Launcher。
二.Activity管理
1.結構圖
2.ActivityDisplay
???????ActivityDisplay與系統(tǒng)屏幕對應，屬于AMS管理Activity的頂層數據結構；
2.1.構建
???????在ActivityStackSupervisor內通過DMS遍歷系統(tǒng)Display創(chuàng)建ActivityDisplay，具體實現(xiàn)邏輯是在setWindowManager()方法內部：
void setWindowManager(WindowManagerService wm) {
synchronized (mService) {
mWindowManager = wm;
mKeyguardController.setWindowManager(wm);
mDisplayManager =
(DisplayManager)mService.mContext.getSystemService(Context.DISPLAY_SERVICE);
mDisplayManager.registerDisplayListener(this, null);
mDisplayManagerInternal = LocalServices.getService(DisplayManagerInternal.class);
Display[] displays = mDisplayManager.getDisplays();
for (int displayNdx = displays.length - 1; displayNdx >= 0; --displayNdx) {
final int displayId = displays[displayNdx].getDisplayId();
ActivityDisplay activityDisplay = new ActivityDisplay(displayId);
if (activityDisplay.mDisplay == null) {
throw new IllegalStateException("Default Display does not exist");
}
mActivityDisplays.put(displayId, activityDisplay);
calculateDefaultMinimalSizeOfResizeableTasks(activityDisplay);
}
mHomeStack = mFocusedStack = mLastFocusedStack =
getStack(HOME_STACK_ID, CREATE_IF_NEEDED, ON_TOP);
mInputManagerInternal = LocalServices.getService(InputManagerInternal.class);
}
}
???????根據前面的分析，在AMS構造方法內部創(chuàng)建ActivityStackSupervisor實例，根據調用關系，setWindowManager()是在SystemServer內部的startOtherServices()內部通過AMS來間接調用的，從而實現(xiàn)了ActivityDisplay的構建；
2.2.管理
???????通過ActivityStackSupervisor內部的mActivityDisplays進行管理；
3.ActivityStack
???????ActivityStack負責Activity在AMS的棧管理，用來記錄已經啟動的Activity的先后關系，狀態(tài)信息等；
3.1.構建
???????根據前面的分析，在setWindowManager()內部會進行創(chuàng)建初始的ActivityStack；
mHomeStack = mFocusedStack = mLastFocusedStack = getStack(HOME_STACK_ID, CREATE_IF_NEEDED, ON_TOP);
???????mHomeStack管理的是Launcher相關的Activity棧；mFocusedStack管理的是當前顯示在前臺Activity的Activity棧；mLastFocusedStack管理的是上一次顯示在前臺Activity的Activity棧；
???????在執(zhí)行getStack()時會創(chuàng)建ActivityStack實例，看一下構造方法實現(xiàn)：
ActivityStack(ActivityStackSupervisor.ActivityDisplay display, int stackId,
ActivityStackSupervisor supervisor, RecentTasks recentTasks, boolean onTop) {
mStackSupervisor = supervisor;
mService = supervisor.mService;
mHandler = new ActivityStackHandler(mService.mHandler.getLooper());
mWindowManager = mService.mWindowManager;
mStackId = stackId;
mCurrentUser = mService.mUserController.getCurrentUserIdLocked();
mRecentTasks = recentTasks;
mTaskPositioner = mStackId == FREEFORM_WORKSPACE_STACK_ID
? new LaunchingTaskPositioner() : null;
mTmpRect2.setEmpty();
mWindowContainerController = createStackWindowController(display.mDisplayId, onTop,
mTmpRect2);
mStackSupervisor.mStacks.put(mStackId, this);
postAddToDisplay(display, mTmpRect2.isEmpty() ? null : mTmpRect2, onTop);
}
3.2.管理
???????新創(chuàng)建的ActivityStack會被存入ActivityStackSupervisor內部的mStacks進行管理；在postAddToDisplay()內部同時會將新創(chuàng)建的ActivityStack存入ActivityDisplay內部的mStacks進行管理；
3.3.類型
???????系統(tǒng)定義了不同類型的Stack，每一個Stack用于容納特定的類型的Activity，主要類型有以下幾種：
???????1.HOME_STACK_ID：存放home activity；
???????2.FULLSCREEN_WORKSPACE_STACK_ID：普通的Activity；
???????3.PINNED_STACK_ID：畫中畫Activity；
???????4.RECENTS_STACK_ID：Recents Activity；
4.TaskRecord
???????內部維護一個 ArrayList<ActivityRecord> 用來保存ActivityRecord，TaskRecord中的mStack表示其所在的ActivityStack，TaskRecord與ActivityStack建立了聯(lián)系；
5.簡單總結
三.Activity啟動構建
1.啟動模式
???????Activity啟動有四種模式：
1.1.standard
???????標準啟動模式，也是activity的默認啟動模式，在這種模式下啟動的activity可以被多次實例化，即在同一個任務中可以存在多個activity的實例，每個實例都會處理一個Intent對；
1.2.singleTop
???????啟動的Activity已經在頂部會復用，如果不在頂部則和standard類似，會重復創(chuàng)建實例；
???????如果一個以singleTop模式啟動的activity的實例已經存在于任務桟的桟頂，那么再啟動這個Activity時，不會創(chuàng)建新的實例，而是重用位于棧頂的那個實例，并且會調用該實例的onNewIntent()方法將Intent對象傳遞到這個實例中；
???????如果以singleTop模式啟動的activity的一個實例已經存在與任務桟中，但是不在桟頂，那么它的行為和standard模式相同，也會創(chuàng)建多個實例；
1.3.singleTask
???????如果一個activity的啟動模式為singleTask，那么系統(tǒng)總會在一個新任務的最底部(root)啟動這個activity，并且被這個activity啟動的其他activity會和該activity同時存在于這個新任務中。
???????如果系統(tǒng)中已經存在這樣的一個activity則會重用這個實例，清除位于SecondActivity上面的所有Activity，顯示SecondActivity，并且調用他的onNewIntent()方法，即這樣的一個activity在系統(tǒng)中只會存在一個實例。
1.4.singleInstance
???????總是在新的任務中開啟，并且這個新的任務中有且只有這一個實例，也就是說被該實例啟動的其他activity會自動運行于另一個任務中。當再次啟動該activity的實例時，會重用已存在的任務和實例。并且會調用這個實例的onNewIntent()方法，將Intent實例傳遞到該實例中。和singleTask相同，同一時刻在系統(tǒng)中只會存在一個這樣的Activity實例。
1.5.taskAffinity
???????可以翻譯為任務相關性。這個參數標識了一個 Activity 所需要的任務棧的名字，默認情況下所有Activity所需的任務棧的名字為應用的包名，當Activity設置了 taskAffinity屬性，那么這個Activity在被創(chuàng)建時就會運行在和taskAffinity名字相同的任務棧中，如果沒有，則新建taskAffinity指定的任務棧，并將Activity放入該棧中；另外，taskAffinity屬性主要和singleTask或者
allowTaskReparenting屬性配對使用，在其他情況下沒有意義。
2.創(chuàng)建ActivityRecord
???????在通過startActivity()啟動Activity時，會先創(chuàng)建ActivityRecord，具體實現(xiàn)是在AcvityStarter內部的startActivity()方法：
ActivityRecord r = new ActivityRecord(mService, callerApp, callingPid, callingUid,
callingPackage, intent, resolvedType, aInfo, mService.getGlobalConfiguration(),
resultRecord, resultWho, requestCode, componentSpecified, voiceSession != null,
mSupervisor, options, sourceRecord);
return startActivity(r, sourceRecord, voiceSession, voiceInteractor, startFlags, true,
options, inTask, outActivity);
???????根據Intent及ActivityInfo信息來構建ActivityRecord，然后調用startActivity來執(zhí)行后續(xù)邏輯；
3.初始化
???????跟隨調用關系，會調用到ActivityStarter內部的startActivityUnchecked()方法會調用到setInitialState()方法：
private void setInitialState(ActivityRecord r, ActivityOptions options, TaskRecord inTask,
boolean doResume, int startFlags, ActivityRecord sourceRecord,
IVoiceInteractionSession voiceSession, IVoiceInteractor voiceInteractor) {
reset();
mStartActivity = r;
mIntent = r.intent;
mOptions = options;
mSourceRecord = sourceRecord;
.....................
mSourceDisplayId = getSourceDisplayId(mSourceRecord, mStartActivity);
.................................
mLaunchSingleTop = r.launchMode == LAUNCH_SINGLE_TOP;
mLaunchSingleInstance = r.launchMode == LAUNCH_SINGLE_INSTANCE;
mLaunchSingleTask = r.launchMode == LAUNCH_SINGLE_TASK;
.....................
.....................
}
???????進行一些初始化賦值操作，將要啟動的ActivityRecord賦值給mStartActivity等，根據r.launchMode來確定對應的LaunchMode；
4.確定Launch Mode和Flags
???????主要通過adjustLaunchFlagsToDocumentMode()及computeLaunchingTaskFlags()進行調整計算：
private void computeLaunchingTaskFlags() {
........................
..........................
if (mInTask == null) {
if (mSourceRecord == null) {
// This activity is not being started from another... in this case we -always- start a new task.
if ((mLaunchFlags & FLAG_ACTIVITY_NEW_TASK) == 0 && mInTask == null) {
Slog.w(TAG, "startActivity called from non-Activity context; forcing " +
"Intent.FLAG_ACTIVITY_NEW_TASK for: " + mIntent);
mLaunchFlags |= FLAG_ACTIVITY_NEW_TASK;
}
} else if (mSourceRecord.launchMode == LAUNCH_SINGLE_INSTANCE) {
// The original activity who is starting us is running as a single
// instance... this new activity it is starting must go on its own task.
mLaunchFlags |= FLAG_ACTIVITY_NEW_TASK;
} else if (mLaunchSingleInstance || mLaunchSingleTask) {
// The activity being started is a single instance... it always
// gets launched into its own task.
mLaunchFlags |= FLAG_ACTIVITY_NEW_TASK;
}
}
}
???????mInTask為null時，會默認添加FLAG_ACTIVITY_NEW_TASK；如果mSourceRecord.launchMode 是 SingleInstance，那么被他啟動的Activity 需要添加 FLAG_ACTIVITY_NEW_TASK；如果launchMode是 SingleInstance或者 SingleTask 也需要添加 FLAG_ACTIVITY_NEW_TASK。
5.確定目標ActivityStack
???????確定目標ActivityStack的過程就是來初始化ActivityStarter的成員變量mTargetStack，分為在新的Task內進行啟動setTaskFromReuseOrCreateNewTask()或在已有的Task內進行啟動setTaskFromSourceRecord()等，主要來看一下setTaskFromReuseOrCreateNewTask()：
private int setTaskFromReuseOrCreateNewTask(
TaskRecord taskToAffiliate, int preferredLaunchStackId, ActivityStack topStack) {
mTargetStack = computeStackFocus(
mStartActivity, true, mLaunchBounds, mLaunchFlags, mOptions);
..................
...................
return START_SUCCESS;
}
???????在該方法內部會調用computeStackFocus()來確定mTargetStack，看一下邏輯實現(xiàn)：
private ActivityStack computeStackFocus(ActivityRecord r, boolean newTask, Rect bounds,
int launchFlags, ActivityOptions aOptions) {
final TaskRecord task = r.getTask();
ActivityStack stack = getLaunchStack(r, launchFlags, task, aOptions);
if (stack != null) {
return stack;
}
........................
if (stack == null) {
// We first try to put the task in the first dynamic stack on home display.
final ArrayList<ActivityStack> homeDisplayStacks = mSupervisor.mHomeStack.mStacks;
for (int stackNdx = homeDisplayStacks.size() - 1; stackNdx >= 0; --stackNdx) {
stack = homeDisplayStacks.get(stackNdx);
if (isDynamicStack(stack.mStackId)) {
if (DEBUG_FOCUS || DEBUG_STACK) Slog.d(TAG_FOCUS,
"computeStackFocus: Setting focused stack=" + stack);
return stack;
}
}
// If there is no suitable dynamic stack then we figure out which static stack to use.
final int stackId = task != null ? task.getLaunchStackId() :
bounds != null ? FREEFORM_WORKSPACE_STACK_ID :
FULLSCREEN_WORKSPACE_STACK_ID;
stack = mSupervisor.getStack(stackId, CREATE_IF_NEEDED, ON_TOP);
}
if (DEBUG_FOCUS || DEBUG_STACK) Slog.d(TAG_FOCUS, "computeStackFocus: New stack r="
+ r + " stackId=" + stack.mStackId);
return stack;
}
???????主要分為三種場景：
???????1.在getLaunchStack()內部根據Activity的屬性定位指定的ActivityStack；
if (r.isHomeActivity()) {
return mSupervisor.mHomeStack;
}
if (r.isRecentsActivity()) {
return mSupervisor.getStack(RECENTS_STACK_ID, CREATE_IF_NEEDED, ON_TOP);
}
if (r.isAssistantActivity()) {
return mSupervisor.getStack(ASSISTANT_STACK_ID, CREATE_IF_NEEDED, ON_TOP);
}
???????2.在Activity啟動的時候Bundle是否指定了DisplayId或StackId(兩者不能同時指定)；
final int launchDisplayId = (aOptions != null) ? aOptions.getLaunchDisplayId() : INVALID_DISPLAY;
final int launchStackId = (aOptions != null) ? aOptions.getLaunchStackId() : INVALID_STACK_ID;
if (launchStackId != INVALID_STACK_ID && launchDisplayId != INVALID_DISPLAY) {
throw new IllegalArgumentException("Stack and display id can't be set at the same time.");
}
if (isValidLaunchStackId(launchStackId, launchDisplayId, r)) {
return mSupervisor.getStack(launchStackId, CREATE_IF_NEEDED, ON_TOP);
}
???????3.不符合以上條件時，會返回stackId為FULLSCREEN_WORKSPACE_STACK_ID的ActivityStack；
final int stackId = task != null ? task.getLaunchStackId() :
bounds != null ? FREEFORM_WORKSPACE_STACK_ID :
FULLSCREEN_WORKSPACE_STACK_ID;
stack = mSupervisor.getStack(stackId, CREATE_IF_NEEDED, ON_TOP);
6.確定TaskRecord
???????在前面setTaskFromReuseOrCreateNewTask()內部在獲取到mTargetStack后，會通過其來創(chuàng)建TaskRecord，再來看一下：
private int setTaskFromReuseOrCreateNewTask(
TaskRecord taskToAffiliate, int preferredLaunchStackId, ActivityStack topStack) {
mTargetStack = computeStackFocus(
mStartActivity, true, mLaunchBounds, mLaunchFlags, mOptions);
if (mReuseTask == null) {
final TaskRecord task = mTargetStack.createTaskRecord(
mSupervisor.getNextTaskIdForUserLocked(mStartActivity.userId),
mNewTaskInfo != null ? mNewTaskInfo : mStartActivity.info,
mNewTaskIntent != null ? mNewTaskIntent : mIntent, mVoiceSession,
mVoiceInteractor, !mLaunchTaskBehind /* toTop */, mStartActivity.mActivityType);
addOrReparentStartingActivity(task, "setTaskFromReuseOrCreateNewTask - mReuseTask");
.................................
}
.......................
}
???????1.在createTaskRecord()內部會創(chuàng)建TaskRecord實例，然后通過addTask()將其加入到ActivityStack內部的mTaskHistory進行管理；
TaskRecord createTaskRecord(int taskId, ActivityInfo info, Intent intent,
IVoiceInteractionSession voiceSession, IVoiceInteractor voiceInteractor,
boolean toTop, int type) {
TaskRecord task = new TaskRecord(mService, taskId, info, intent, voiceSession,
voiceInteractor, type);
// add the task to stack first, mTaskPositioner might need the stack association
addTask(task, toTop, "createTaskRecord");
..............
task.createWindowContainer(toTop, (info.flags & FLAG_SHOW_FOR_ALL_USERS) != 0);
return task;
}
???????2.通過addOrReparentStartingActivity()內部將ActivityRecord添加到新創(chuàng)建的TaskRecord中；
private void addOrReparentStartingActivity(TaskRecord parent, String reason) {
if (mStartActivity.getTask() == null || mStartActivity.getTask() == parent) {
parent.addActivityToTop(mStartActivity);
}
........................
}
void addActivityToTop(ActivityRecord r) {
addActivityAtIndex(mActivities.size(), r);
}
void addActivityAtIndex(int index, ActivityRecord r) {
TaskRecord task = r.getTask();
r.setTask(this);
.........................
mActivities.add(index, r);
.........................
}
???????ActivityRecord通過setTask(this)與TaskRecord建立聯(lián)系，TaskRecord將ActivityRecord加入到mActivities進行管理；
7.與WMS關聯(lián)
???????Activity在啟動時，會根據ActivityRecord確定ActivityStack、TaskRecord，在創(chuàng)建以上時，都會在WMS創(chuàng)建對應的管理者，在ActivityStack的startActivityLocked()內部會創(chuàng)建ActivityRecord在WMS對應的管理著，本文就不展開分析了，列出對應關系圖如下：
四.其他
???????關于Activity啟動及顯示可以參考以下文章：
???????Android activity啟動流程分析
???????Android View 顯示原理分析
???????關于AMS關聯(lián)可以參以下文章：
???????Android WMS窗口管理
???????Android WMS窗口管理(二)
