在上一節(jié)中定欧，我們分析了從點(diǎn)擊桌面上一個(gè)App的圖標(biāo)啟動(dòng)App到ActivityManagerService中的源碼匹耕，這一次我們就開(kāi)始真正的分析AMS在接到開(kāi)啟Actiivty的請(qǐng)求后是如何一步步具體的開(kāi)啟的聚请。
三.AMS到Activity
上一節(jié)中，我們的源碼已經(jīng)到了frameworks/base/services/core/java/com/android/server/am/ActivityManagerService.java中的
@Override
public final int startActivity(IApplicationThread caller, String callingPackage,
Intent intent, String resolvedType, IBinder resultTo, String resultWho, int requestCode,
int startFlags, ProfilerInfo profilerInfo, Bundle options) {
return startActivityAsUser(caller, callingPackage, intent, resolvedType, resultTo,
resultWho, requestCode, startFlags, profilerInfo, options,
UserHandle.getCallingUserId());
}
@Override
public final int startActivityAsUser(IApplicationThread caller, String callingPackage,
Intent intent, String resolvedType, IBinder resultTo, String resultWho, int requestCode,
int startFlags, ProfilerInfo profilerInfo, Bundle options, int userId) {
enforceNotIsolatedCaller("startActivity");
userId = handleIncomingUser(Binder.getCallingPid(), Binder.getCallingUid(), userId,
false, ALLOW_FULL_ONLY, "startActivity", null);
// TODO: Switch to user app stacks here.
return mStackSupervisor.startActivityMayWait(caller, -1, callingPackage, intent,
resolvedType, null, null, resultTo, resultWho, requestCode, startFlags,
profilerInfo, null, null, options, false, userId, null, null);
}
這里出現(xiàn)了一個(gè)新的對(duì)象:mStackSupervisor，他是ActivityStackSupervisor類(lèi)的對(duì)象驶赏，而這個(gè)Supervisor是"主管"的意思炸卑，簡(jiǎn)單來(lái)說(shuō)，ActivityStackSupervisor類(lèi)就是“ActivityStack的主管”煤傍，而ActivityStack我們前面說(shuō)過(guò)盖文，他是Activity在AMS的棧管理，用來(lái)記錄已經(jīng)啟動(dòng)的Activity的先后關(guān)系蚯姆，狀態(tài)信息等五续。通過(guò)ActivityStack決定是否需要啟動(dòng)新的進(jìn)程。因此可知這個(gè)類(lèi)是管理ActivityStack的類(lèi)龄恋。我們接著看源碼:
final int startActivityMayWait(IApplicationThread caller, int callingUid,
String callingPackage, Intent intent, String resolvedType,
IVoiceInteractionSession voiceSession, IVoiceInteractor voiceInteractor,
IBinder resultTo, String resultWho, int requestCode, int startFlags,
ProfilerInfo profilerInfo, WaitResult outResult, Configuration config,
Bundle options, boolean ignoreTargetSecurity, int userId,
IActivityContainer iContainer, TaskRecord inTask) {
// Refuse possible leaked file descriptors
if (intent != null && intent.hasFileDescriptors()) {
throw new IllegalArgumentException("File descriptors passed in Intent");
}
boolean componentSpecified = intent.getComponent() != null;
// Don't modify the client's object!
//新建一個(gè)Intent對(duì)象疙驾，并且這里的注釋告訴我們不要修改客戶端的對(duì)象.
intent = new Intent(intent);
// Collect information about the target of the Intent.
//收集Intent所指向的Activity信息，當(dāng)存在多個(gè)可供選擇的Activity郭毕，則直接指向用選擇的resolveActivity
ActivityInfo aInfo =
resolveActivity(intent, resolvedType, startFlags, profilerInfo, userId);
synchronized (mService) {
if (container != null && container.mParentActivity != null &&
container.mParentActivity.state != RESUMED) {
// Cannot start a child activity if the parent is not resumed.
return ActivityManager.START_CANCELED;
}
......
int res = startActivityLocked(caller, intent, resolvedType, aInfo,
voiceSession, voiceInteractor, resultTo, resultWho,
requestCode, callingPid, callingUid, callingPackage,
realCallingPid, realCallingUid, startFlags, options, ignoreTargetSecurity,
componentSpecified, null, container, inTask);
......
return res;
}
}
我們來(lái)看看這個(gè)resolveActivity(),在這個(gè)方法中借助PackageManager來(lái)查詢系統(tǒng)中符合要求的Activity,當(dāng)存在多個(gè)滿足條件的Activity的時(shí)候則會(huì)彈框讓用戶來(lái)選擇:
ActivityInfo resolveActivity(Intent intent, String resolvedType, int startFlags,
ProfilerInfo profilerInfo, int userId) {
// Collect information about the target of the Intent.
ActivityInfo aInfo;
try {
ResolveInfo rInfo =
AppGlobals.getPackageManager().resolveIntent(
intent, resolvedType,
PackageManager.MATCH_DEFAULT_ONLY
| ActivityManagerService.STOCK_PM_FLAGS, userId);
aInfo = rInfo != null ? rInfo.activityInfo : null;
} catch (RemoteException e) {
aInfo = null;
}
if (aInfo != null) {
// Store the found target back into the intent, because now that
// we have it we never want to do this again. For example, if the
// user navigates back to this point in the history, we should
// always restart the exact same activity.
intent.setComponent(new ComponentName(
aInfo.applicationInfo.packageName, aInfo.name));
// Don't debug things in the system process
if ((startFlags&ActivityManager.START_FLAG_DEBUG) != 0) {
if (!aInfo.processName.equals("system")) {
mService.setDebugApp(aInfo.processName, true, false);
}
}
if ((startFlags&ActivityManager.START_FLAG_OPENGL_TRACES) != 0) {
if (!aInfo.processName.equals("system")) {
mService.setOpenGlTraceApp(aInfo.applicationInfo, aInfo.processName);
}
}
if (profilerInfo != null) {
if (!aInfo.processName.equals("system")) {
mService.setProfileApp(aInfo.applicationInfo, aInfo.processName, profilerInfo);
}
}
}
return aInfo;
}
注意這個(gè)方法中的intent.setComponent(new ComponentName( aInfo.applicationInfo.packageName, aInfo.name));這句荆萤，這里的aInfo.name為main Activity,????如:com.my.test.MainActivity，aInfo.applicationInfo.packageName為包名铣卡，如com.my.test ，也就是說(shuō)偏竟，通過(guò)這個(gè)方法煮落，我們new出來(lái)的這個(gè)intent對(duì)象知道了他要打開(kāi)的Activty的類(lèi)名和包名!!!
另外這個(gè)方法中，ActivityManager類(lèi)有如下4個(gè)flags用于調(diào)試:
????START_FLAG_DEBUG:用于調(diào)試debug app
????START_FLAG_OPENGL_TRACES:用于調(diào)試OpenGL tracing
????START_FLAG_NATIVE_DEBUGGING:用于調(diào)試native
????START_FLAG_TRACK_ALLOCATION: 用于調(diào)試allocation tracking
????這里我們可以說(shuō)一點(diǎn)題外話注意到AppGlobals.getPackageManager().resolveIntent( intent, resolvedType, PackageManager.MATCH_DEFAULT_ONL | ActivityManagerService.STOCK_PM_FLAGS, userId);這句代碼踊谋，如果我們點(diǎn)進(jìn)去resolveIntent()的話就會(huì)發(fā)現(xiàn)進(jìn)入了一個(gè)接口類(lèi):IPackageManager——大家看到這里有沒(méi)有覺(jué)得這個(gè)名字有點(diǎn)眼熟呢蝉仇？還記得我們上一篇再講ActivityManagerService與客戶端的交互的時(shí)候是通過(guò)一個(gè)接口類(lèi)IActivityManager嗎？沒(méi)錯(cuò)殖蚕，這里獲取包名的代碼結(jié)構(gòu)跟上面類(lèi)似轿衔，那么實(shí)現(xiàn)IPackageManager借口的類(lèi)是什么呢？想必大家已經(jīng)猜到了——沒(méi)錯(cuò)就是PackageManagerService!!!至于類(lèi)名具體獲取的方式有興趣的讀者可以進(jìn)入該類(lèi)具體研究睦疫，我們繼續(xù)看ActivityStackSupervisor類(lèi)中的代碼:
ActivityStackSupervisor.java:
回到startActivityMayWait()方法中害驹，直接看下面這段代碼:int res = startActivityLocked(caller, intent, resolvedType, aInfo,voiceSession, voiceInteractor, resultTo, resultWho,requestCode, callingPid, callingUid, callingPackage,realCallingPid, realCallingUid, startFlags, options,ignoreTargetSecurity,componentSpecified, null, container, inTask
????這里的Locked表示這個(gè)函數(shù)是線程安全的，即該函數(shù)只能由一個(gè)線程調(diào)用蛤育。如果另一個(gè)線程要調(diào)用該函數(shù)宛官，必須等上一個(gè)線程執(zhí)行完，所以我們?cè)诰唧w的函數(shù)體中會(huì)發(fā)現(xiàn)很多檢查是否允許切換APP的方法瓦糕。該函數(shù)的功能有:
- 檢查當(dāng)前正在運(yùn)行的Activity是否和目標(biāo)Activity一致底洗，如果一致則直接返回。也就是說(shuō)咕娄，我們?cè)谑褂胹tartActivity啟動(dòng)的是目標(biāo)Activity亥揖，不會(huì)重啟當(dāng)前Activity。
- 處理INTENT_FLAG_FORWARD_RESULT標(biāo)志圣勒，在代碼中此標(biāo)志能跨Activity傳遞Result费变。
- 檢查是否存在Caller(Launcher所在進(jìn)程)的App摧扇，此功能出現(xiàn)在發(fā)出startActivity命令之后。如果Caller所在的進(jìn)程被意外殺死或關(guān)閉胡控，那么AMS將拒絕往下執(zhí)行命令扳剿。
- 檢查caller是否具備啟動(dòng)指定Activity的權(quán)限。
final int startActivityLocked(IApplicationThread caller,
Intent intent, String resolvedType, ActivityInfo aInfo,
IVoiceInteractionSession voiceSession, IVoiceInteractor voiceInteractor,
IBinder resultTo, String resultWho, int requestCode,
int callingPid, int callingUid, String callingPackage,
int realCallingPid, int realCallingUid, int startFlags, Bundle options,
boolean ignoreTargetSecurity, boolean componentSpecified, ActivityRecord[] outActivity,
ActivityContainer container, TaskRecord inTask) {
/**
* Result for IActivityManaqer.startActivity: the activity was started
* successfully as normal.
* @hide
*/
int err = ActivityManager.START_SUCCESS;
//獲取調(diào)用者(Launcher)的進(jìn)程記錄對(duì)象昼激。
ProcessRecord callerApp = null;
if (caller != null) {
callerApp = mService.getRecordForAppLocked(caller);
if (callerApp != null) {
callingPid = callerApp.pid;
callingUid = callerApp.info.uid;
} else {
/**
* Result for IActivityManager.startActivity: an error where the
* caller does not have permission to start the activity.
* @hide
*/
err = ActivityManager.START_PERMISSION_DENIED;
}
}
final int userId = aInfo != null ? UserHandle.getUserId(aInfo.applicationInfo.uid) : 0;
......
ActivityRecord sourceRecord = null;
ActivityRecord resultRecord = null;
if (resultTo != null) {
//獲取調(diào)用者(Launcher類(lèi))所在的Activity
sourceRecord = isInAnyStackLocked(resultTo);
if (sourceRecord != null) {
if (requestCode >= 0 && !sourceRecord.finishing) {
resultRecord = sourceRecord;
}
}
}
final int launchFlags = intent.getFlags();
if ((launchFlags & Intent.FLAG_ACTIVITY_FORWARD_RESULT) != 0 && sourceRecord != null) {
// Transfer the result target from the source activity to the new
// one being started, including any failures.
... // activity執(zhí)行結(jié)果的返回由源Activity轉(zhuǎn)換到新Activity, 不需要返回結(jié)果則不會(huì)進(jìn)入該分支
}
if (err == ActivityManager.START_SUCCESS && intent.getComponent() == null) {
// We couldn't find a class that can handle the given Intent.
// That's the end of that!
//從Intent中無(wú)法找到相應(yīng)的Component
err = ActivityManager.START_INTENT_NOT_RESOLVED;
}
if (err == ActivityManager.START_SUCCESS && aInfo == null) {
// We couldn't find the specific class specified in the Intent.
// Also the end of the line.
//從Intent中無(wú)法找到相應(yīng)的ActivityInfo
err = ActivityManager.START_INTENT_NOT_RESOLVED;
}
if (err == ActivityManager.START_SUCCESS
&& !isCurrentProfileLocked(userId)
&& (aInfo.flags & FLAG_SHOW_FOR_ALL_USERS) == 0) {
// Trying to launch a background activity that doesn't show for all users.
//嘗試啟動(dòng)一個(gè)后臺(tái)Activity, 但該Activity對(duì)當(dāng)前用戶不可見(jiàn)
err = ActivityManager.START_NOT_CURRENT_USER_ACTIVITY;
}
...
//執(zhí)行后resultStack = null
final ActivityStack resultStack = resultRecord == null ? null : resultRecord.task.stack;
if (err != ActivityManager.START_SUCCESS) {
//前面步驟存在err,執(zhí)行到這里將會(huì)直接返回
if (resultRecord != null) {
resultStack.sendActivityResultLocked(-1,
resultRecord, resultWho, requestCode,
Activity.RESULT_CANCELED, null);
}
ActivityOptions.abort(options);
return err;
}
... //權(quán)限檢查
if (abort) {
//權(quán)限檢查不滿足,才進(jìn)入該分支則直接返回庇绽；
if (resultRecord != null) {
resultStack.sendActivityResultLocked(-1, resultRecord, resultWho, requestCode,
Activity.RESULT_CANCELED, null);
}
// We pretend to the caller that it was really started, but
// they will just get a cancel result.
ActivityOptions.abort(options);
return ActivityManager.START_SUCCESS;
}
//將要?jiǎng)?chuàng)建的Activity的記錄對(duì)象。
ActivityRecord r = new ActivityRecord(mService, callerApp, callingUid, callingPackage,
intent, resolvedType, aInfo, mService.mConfiguration, resultRecord, resultWho,
requestCode, componentSpecified, voiceSession != null, this, container, options);
if (outActivity != null) {
outActivity[0] = r;
}
if (r.appTimeTracker == null && sourceRecord != null) {
// If the caller didn't specify an explicit time tracker, we want to continue
// tracking under any it has.
r.appTimeTracker = sourceRecord.appTimeTracker;
}
// 將mFocusedStack賦予當(dāng)前stack橙困，這個(gè)mFocusedStack是The stack currently receiving input or
//launching the next activity瞧掺，也就是ActivityStack這個(gè)棧當(dāng)前正在接入或者啟動(dòng)的棧。
final ActivityStack stack = mFocusedStack;
// 前臺(tái)stack還沒(méi)有resume狀態(tài)的Activity時(shí), 則檢查app切換是否允許
if (voiceSession == null && (stack.mResumedActivity == null
|| stack.mResumedActivity.info.applicationInfo.uid != callingUid)) {
if (!mService.checkAppSwitchAllowedLocked(callingPid, callingUid,
realCallingPid, realCallingUid, "Activity start")) {
PendingActivityLaunch pal =
new PendingActivityLaunch(r, sourceRecord, startFlags, stack);
// 當(dāng)不允許切換,則把要啟動(dòng)的Activity添加到mPendingActivityLaunches對(duì)象, 并且直接返回.
mPendingActivityLaunches.add(pal);
ActivityOptions.abort(options);
return ActivityManager.START_SWITCHES_CANCELED;
}
}
if (mService.mDidAppSwitch) {
//從上次禁止app切換以來(lái),這是第二次允許app切換,因此將允許切換時(shí)間設(shè)置為0,則表示可以任意切換app
mService.mAppSwitchesAllowedTime = 0;
} else {
mService.mDidAppSwitch = true;
}
//處理 pendind Activity的啟動(dòng), 這些Activity是由于app switch禁用從而被hold的等待啟動(dòng)activity
doPendingActivityLaunchesLocked(false);
err = startActivityUncheckedLocked(r, sourceRecord, voiceSession, voiceInteractor,
startFlags, true, options, inTask);
if (err < 0) {
notifyActivityDrawnForKeyguard();
}
return err;
這個(gè)方法比較繁復(fù)凡傅，也就是重頭戲開(kāi)始的地方:這個(gè)類(lèi)中出現(xiàn)了幾個(gè)值得注意的對(duì)象——ActivityStack,ActivityRecord,ProcessRecord辟狈。還記得我們?cè)诘谝还?jié)中說(shuō)過(guò)這幾個(gè)對(duì)象的意義嗎？
-
ActivityStack
Activity在AMS的棧管理夏跷，用來(lái)記錄已經(jīng)啟動(dòng)的Activity先后順序哼转，狀態(tài)信息等。通過(guò)ActivityStack決定是否需要啟動(dòng)新的進(jìn)程槽华。 -
ActivityRecord
ActivityStack的管理對(duì)象壹蔓，每個(gè)Activity在AMS對(duì)應(yīng)的一個(gè)ActiivtyRecord，來(lái)記錄Activity的狀態(tài)及其他管理信息猫态。 -
TaskRecord
AMS抽象出來(lái)的一個(gè)“任務(wù)”的概念佣蓉，是記錄ActivityRecord的棧，一個(gè)“Task”包含若干個(gè)ActivityRecord亲雪。AMS用TaskRecord確保Activity的q啟動(dòng)和退出順序勇凭。 -
ProcessRecord
一個(gè)APK文件運(yùn)行時(shí)會(huì)對(duì)應(yīng)一個(gè)進(jìn)程，ProcessRecord正是記錄一個(gè)進(jìn)程相關(guān)的信息义辕。
這里我們需要注意的是虾标，整個(gè)startActiviyLocked()方法返回的是一個(gè)int型的值，也就是ActivityManager類(lèi)中封裝的一系列標(biāo)志位用以表示Activity啟動(dòng)的成功與否或者錯(cuò)誤的原因:
public static final int START_NOT_CURRENT_USER_ACTIVITY = -8;
public static final int START_NOT_VOICE_COMPATIBLE = -7;
public static final int START_CANCELED = -6;
public static final int START_NOT_ACTIVITY = -5;
public static final int START_PERMISSION_DENIED = -4;
public static final int START_FORWARD_AND_REQUEST_CONFLICT = -3;
public static final int START_CLASS_NOT_FOUND = -2;
public static final int START_INTENT_NOT_RESOLVED = -1;
public static final int START_SUCCESS = 0;
......
經(jīng)過(guò)一系列的權(quán)限及線程檢查灌砖，我們終于執(zhí)行到了err = startActivityUncheckedLocked(r, sourceRecord, voiceSession, voiceInteractor,startFlags, true, options, inTask);這個(gè)函數(shù)夺巩，此時(shí)要啟動(dòng)的目標(biāo)Activity我們已經(jīng)認(rèn)為是一個(gè)“健康安全合法”的啟動(dòng)請(qǐng)求。我們看具體startActivityUncheckedLocked()函數(shù)中的代碼,該方法更加繁復(fù)周崭，有600多行代碼柳譬，我們刪去一些:
final int startActivityUncheckedLocked(final ActivityRecord r, ActivityRecord sourceRecord,
IVoiceInteractionSession voiceSession, IVoiceInteractor voiceInteractor, int startFlags,
boolean doResume, Bundle options, TaskRecord inTask) {
final Intent intent = r.intent;
final int callingUid = r.launchedFromUid;
if (inTask != null && !inTask.inRecents) {
Slog.w(TAG, "Starting activity in task not in recents: " + inTask);
inTask = null;
}
//這里出現(xiàn)了Activity的不同啟動(dòng)模式
final boolean launchSingleTop = r.launchMode == ActivityInfo.LAUNCH_SINGLE_TOP;
final boolean launchSingleInstance = r.launchMode == ActivityInfo.LAUNCH_SINGLE_INSTANCE;
final boolean launchSingleTask = r.launchMode == ActivityInfo.LAUNCH_SINGLE_TASK;
int launchFlags = intent.getFlags();
if ((launchFlags & Intent.FLAG_ACTIVITY_NEW_DOCUMENT) != 0 &&
(launchSingleInstance || launchSingleTask)) {
// We have a conflict between the Intent and the Activity manifest, manifest wins.
// 當(dāng)intent和activity manifest存在沖突，則manifest優(yōu)先
Slog.i(TAG, "Ignoring FLAG_ACTIVITY_NEW_DOCUMENT, launchMode is " +
"\"singleInstance\" or \"singleTask\"");
launchFlags &=
~(Intent.FLAG_ACTIVITY_NEW_DOCUMENT | Intent.FLAG_ACTIVITY_MULTIPLE_TASK);
} else {
......
}
......
if (((launchFlags & Intent.FLAG_ACTIVITY_NEW_TASK) != 0 &&
(launchFlags & Intent.FLAG_ACTIVITY_MULTIPLE_TASK) == 0)
|| launchSingleInstance || launchSingleTask) {
if (inTask == null && r.resultTo == null) {
ActivityRecord intentActivity = !launchSingleInstance ?
findTaskLocked(r) : findActivityLocked(intent, r.info);
if (intentActivity != null) {
if (isLockTaskModeViolation(intentActivity.task,
(launchFlags & (FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TASK))
== (FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TASK))) {
showLockTaskToast();
Slog.e(TAG, "startActivityUnchecked: Attempt to violate Lock Task Mode");
return ActivityManager.START_RETURN_LOCK_TASK_MODE_VIOLATION;
}
if (r.task == null) {
r.task = intentActivity.task;
}
if (intentActivity.task.intent == null) {
intentActivity.task.setIntent(r);
}
targetStack = intentActivity.task.stack;
targetStack.mLastPausedActivity = null;
final ActivityStack focusStack = getFocusedStack();
ActivityRecord curTop = (focusStack == null)
? null : focusStack.topRunningNonDelayedActivityLocked(notTop);
boolean movedToFront = false;
if (curTop != null && (curTop.task != intentActivity.task ||
curTop.task != focusStack.topTask())) {
r.intent.addFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);
if (sourceRecord == null || (sourceStack.topActivity() != null &&
sourceStack.topActivity().task == sourceRecord.task)) {
// We really do want to push this one into the user's face, right now.
if (launchTaskBehind && sourceRecord != null) {
intentActivity.setTaskToAffiliateWith(sourceRecord.task);
}
movedHome = true;
targetStack.moveTaskToFrontLocked(intentActivity.task, noAnimation,
options, r.appTimeTracker, "bringingFoundTaskToFront");
movedToFront = true;
if ((launchFlags &
(FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_TASK_ON_HOME))
== (FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_TASK_ON_HOME)) {
// Caller wants to appear on home activity.
intentActivity.task.setTaskToReturnTo(HOME_ACTIVITY_TYPE);
}
options = null;
}
}
if (!movedToFront) {
targetStack.moveToFront("intentActivityFound");
}
// If the caller has requested that the target task be
// reset, then do so.
if ((launchFlags&Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED) != 0) {
intentActivity = targetStack.resetTaskIfNeededLocked(intentActivity, r);
}
if ((startFlags & ActivityManager.START_FLAG_ONLY_IF_NEEDED) != 0) {
if (doResume) {
resumeTopActivitiesLocked(targetStack, null, options);
// Make sure to notify Keyguard as well if we are not running an app
// transition later.
if (!movedToFront) {
notifyActivityDrawnForKeyguard();
}
} else {
ActivityOptions.abort(options);
}
return ActivityManager.START_RETURN_INTENT_TO_CALLER;
}
if ((launchFlags & (FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TASK))
== (FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TASK)) {
reuseTask = intentActivity.task;
reuseTask.performClearTaskLocked();
reuseTask.setIntent(r);
} else if ((launchFlags & FLAG_ACTIVITY_CLEAR_TOP) != 0
|| launchSingleInstance || launchSingleTask) {
ActivityRecord top =
intentActivity.task.performClearTaskLocked(r, launchFlags);
if (top != null) {
if (top.frontOfTask) {
top.task.setIntent(r);
}
ActivityStack.logStartActivity(EventLogTags.AM_NEW_INTENT,
r, top.task);
top.deliverNewIntentLocked(callingUid, r.intent, r.launchedFromPackage);
} else {
addingToTask = true;
sourceRecord = intentActivity;
TaskRecord task = sourceRecord.task;
if (task != null && task.stack == null) {
// Target stack got cleared when we all activities were removed
// above. Go ahead and reset it.
targetStack = computeStackFocus(sourceRecord, false /* newTask */);
targetStack.addTask(
task, !launchTaskBehind /* toTop */, false /* moving */);
}
}
} else if (r.realActivity.equals(intentActivity.task.realActivity)) {
if (((launchFlags&Intent.FLAG_ACTIVITY_SINGLE_TOP) != 0 || launchSingleTop)
&& intentActivity.realActivity.equals(r.realActivity)) {
ActivityStack.logStartActivity(EventLogTags.AM_NEW_INTENT, r,
intentActivity.task);
if (intentActivity.frontOfTask) {
intentActivity.task.setIntent(r);
}
intentActivity.deliverNewIntentLocked(callingUid, r.intent,
r.launchedFromPackage);
} else if (!r.intent.filterEquals(intentActivity.task.intent)) {
addingToTask = true;
sourceRecord = intentActivity;
}
} else if ((launchFlags&Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED) == 0) {
addingToTask = true;
sourceRecord = intentActivity;
} else if (!intentActivity.task.rootWasReset) {
intentActivity.task.setIntent(r);
}
if (!addingToTask && reuseTask == null) {
if (doResume) {
targetStack.resumeTopActivityLocked(null, options);
if (!movedToFront) {
// Make sure to notify Keyguard as well if we are not running an app
// transition later.
notifyActivityDrawnForKeyguard();
}
} else {
ActivityOptions.abort(options);
}
return ActivityManager.START_TASK_TO_FRONT;
}
}
}
}
if (r.packageName != null) {
//查看當(dāng)前在棧頂端的Activity是否就是即將啟動(dòng)的Activity,在有些情況下续镇，如果即將要啟動(dòng)的
//Activity就在堆棧的頂端美澳，那么就不會(huì)重新啟動(dòng)這個(gè)Activity的另外一個(gè)實(shí)例。
ActivityStack topStack = mFocusedStack;
ActivityRecord top = topStack.topRunningNonDelayedActivityLocked(notTop);
if (top != null && r.resultTo == null) {
if (top.realActivity.equals(r.realActivity) && top.userId == r.userId) {
if (top.app != null && top.app.thread != null) {
if ((launchFlags & Intent.FLAG_ACTIVITY_SINGLE_TOP) != 0
|| launchSingleTop || launchSingleTask) {
ActivityStack.logStartActivity(EventLogTags.AM_NEW_INTENT, top,
top.task);
// For paranoia, make sure we have correctly
// resumed the top activity.
topStack.mLastPausedActivity = null;
if (doResume) {
resumeTopActivitiesLocked();
}
ActivityOptions.abort(options);
if ((startFlags&ActivityManager.START_FLAG_ONLY_IF_NEEDED) != 0) {
return ActivityManager.START_RETURN_INTENT_TO_CALLER;
}
top.deliverNewIntentLocked(callingUid, r.intent, r.launchedFromPackage);
return ActivityManager.START_DELIVERED_TO_TOP;
}
}
}
}
} else {
if (r.resultTo != null && r.resultTo.task.stack != null) {
r.resultTo.task.stack.sendActivityResultLocked(-1, r.resultTo, r.resultWho,
r.requestCode, Activity.RESULT_CANCELED, null);
}
ActivityOptions.abort(options);
return ActivityManager.START_CLASS_NOT_FOUND;
}
boolean newTask = false;
boolean keepCurTransition = false;
TaskRecord taskToAffiliate = launchTaskBehind && sourceRecord != null ?
sourceRecord.task : null;
// Should this be considered a new task?
//因?yàn)橐谝粋€(gè)新的Task里邊來(lái)啟動(dòng)這個(gè)Activity,所以下邊創(chuàng)建一個(gè)新的Activity
if (r.resultTo == null && inTask == null && !addingToTask
&& (launchFlags & Intent.FLAG_ACTIVITY_NEW_TASK) != 0) {
newTask = true;
targetStack = computeStackFocus(r, newTask);
targetStack.moveToFront("startingNewTask");
if (reuseTask == null) {
//創(chuàng)建一個(gè)新的task,即TaskRecord,并保存在ActivityRecord.task中
r.setTask(targetStack.createTaskRecord(getNextTaskId(),
newTaskInfo != null ? newTaskInfo : r.info,
newTaskIntent != null ? newTaskIntent : intent,
voiceSession, voiceInteractor, !launchTaskBehind /* toTop */),
taskToAffiliate);
if (DEBUG_TASKS) Slog.v(TAG_TASKS,
"Starting new activity " + r + " in new task " + r.task);
} else {
r.setTask(reuseTask, taskToAffiliate);
}
if (isLockTaskModeViolation(r.task)) {
Slog.e(TAG, "Attempted Lock Task Mode violation r=" + r);
return ActivityManager.START_RETURN_LOCK_TASK_MODE_VIOLATION;
}
if (!movedHome) {
if ((launchFlags &
(FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_TASK_ON_HOME))
== (FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_TASK_ON_HOME)) {
// Caller wants to appear on home activity, so before starting
// their own activity we will bring home to the front.
r.task.setTaskToReturnTo(HOME_ACTIVITY_TYPE);
}
}
} else if (sourceRecord != null) {
final TaskRecord sourceTask = sourceRecord.task;
if (isLockTaskModeViolation(sourceTask)) {
Slog.e(TAG, "Attempted Lock Task Mode violation r=" + r);
return ActivityManager.START_RETURN_LOCK_TASK_MODE_VIOLATION;
}
targetStack = sourceTask.stack;
targetStack.moveToFront("sourceStackToFront");
final TaskRecord topTask = targetStack.topTask();
if (topTask != sourceTask) {
targetStack.moveTaskToFrontLocked(sourceTask, noAnimation, options,
r.appTimeTracker, "sourceTaskToFront");
}
if (!addingToTask && (launchFlags&Intent.FLAG_ACTIVITY_CLEAR_TOP) != 0) {
ActivityRecord top = sourceTask.performClearTaskLocked(r, launchFlags);
keepCurTransition = true;
if (top != null) {
ActivityStack.logStartActivity(EventLogTags.AM_NEW_INTENT, r, top.task);
top.deliverNewIntentLocked(callingUid, r.intent, r.launchedFromPackage);
// For paranoia, make sure we have correctly
// resumed the top activity.
targetStack.mLastPausedActivity = null;
if (doResume) {
targetStack.resumeTopActivityLocked(null);
}
ActivityOptions.abort(options);
return ActivityManager.START_DELIVERED_TO_TOP;
}
} else if (!addingToTask &&
(launchFlags&Intent.FLAG_ACTIVITY_REORDER_TO_FRONT) != 0) {
// In this case, we are launching an activity in our own task
// that may already be running somewhere in the history, and
// we want to shuffle it to the front of the stack if so.
final ActivityRecord top = sourceTask.findActivityInHistoryLocked(r);
if (top != null) {
final TaskRecord task = top.task;
task.moveActivityToFrontLocked(top);
ActivityStack.logStartActivity(EventLogTags.AM_NEW_INTENT, r, task);
top.updateOptionsLocked(options);
top.deliverNewIntentLocked(callingUid, r.intent, r.launchedFromPackage);
targetStack.mLastPausedActivity = null;
if (doResume) {
targetStack.resumeTopActivityLocked(null);
}
return ActivityManager.START_DELIVERED_TO_TOP;
}
}
......
}
......
ActivityStack.logStartActivity(EventLogTags.AM_CREATE_ACTIVITY, r, r.task);
targetStack.mLastPausedActivity = null;
targetStack.startActivityLocked(r, newTask, doResume, keepCurTransition, options);
if (!launchTaskBehind) {
// Don't set focus on an activity that's going to the back.
mService.setFocusedActivityLocked(r, "startedActivity");
}
return ActivityManager.START_SUCCESS;
}
可以看到這個(gè)方法中對(duì)我們將要啟動(dòng)的Activity做了不同放在了任務(wù)棧的棧頂。最后我們終于看到ActivityStack的startActivityLocked(ActivityRecord r, boolean newTask,boolean doResume, boolean keepCurTransition, Bundle options)ActivityRecord代表的就是要開(kāi)啟的Activity對(duì)象制跟，里面封裝了很多信息舅桩，比如所在的ActivityTask等，如果這是首次打開(kāi)應(yīng)用雨膨，那么這個(gè)Activity會(huì)被放到ActivityTask的棧頂:
final void startActivityLocked(ActivityRecord r, boolean newTask,
boolean doResume, boolean keepCurTransition, Bundle options) {
TaskRecord rTask = r.task;
final int taskId = rTask.taskId;
// mLaunchTaskBehind tasks get placed at the back of the task stack.
if (!r.mLaunchTaskBehind && (taskForIdLocked(taskId) == null || newTask)) {
// Last activity in task had been removed or ActivityManagerService is reusing task.
// Insert or replace.
// Might not even be in.
//task中的上一個(gè)activity已被移除擂涛，或者ams重用該task,則將該task移到頂部
insertTaskAtTop(rTask, r);
mWindowManager.moveTaskToTop(taskId);
}
TaskRecord task = null;
//如果不是在新的ActivityTask(也就是TaskRecord)中的話，就找出要運(yùn)行在的TaskRecord對(duì)象
if (!newTask) {
// If starting in an existing task, find where that is...
boolean startIt = true;
for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {
task = mTaskHistory.get(taskNdx);
if (task.getTopActivity() == null) {
// All activities in task are finishing.
//該task所有activity都finishing
continue;
}
if (task == r.task) {
// Here it is! Now, if this is not yet visible to the
// user, then just add it without starting; it will
// get started when the user navigates back to it.
// 找到了!!!
if (!startIt) {
if (DEBUG_ADD_REMOVE) Slog.i(TAG, "Adding activity " + r + " to task "
+ task, new RuntimeException("here").fillInStackTrace());
task.addActivityToTop(r);
r.putInHistory();
mWindowManager.addAppToken(task.mActivities.indexOf(r), r.appToken,
r.task.taskId, mStackId, r.info.screenOrientation, r.fullscreen,
(r.info.flags & ActivityInfo.FLAG_SHOW_FOR_ALL_USERS) != 0,
r.userId, r.info.configChanges, task.voiceSession != null,
r.mLaunchTaskBehind);
if (VALIDATE_TOKENS) {
validateAppTokensLocked();
}
ActivityOptions.abort(options);
return;
}
break;
} else if (task.numFullscreen > 0) {
startIt = false;
}
}
}
// Place a new activity at top of stack, so it is next to interact
// with the user.
// If we are not placing the new activity frontmost, we do not want
// to deliver the onUserLeaving callback to the actual frontmost
// activity
if (task == r.task && mTaskHistory.indexOf(task) != (mTaskHistory.size() - 1)) {
mStackSupervisor.mUserLeaving = false;
if (DEBUG_USER_LEAVING) Slog.v(TAG_USER_LEAVING,
"startActivity() behind front, mUserLeaving=false");
}
task = r.task;
// Slot the activity into the history stack and proceed
if (DEBUG_ADD_REMOVE) Slog.i(TAG, "Adding activity " + r + " to stack to task " + task,
new RuntimeException("here").fillInStackTrace());
task.addActivityToTop(r);
task.setFrontOfTask();
r.putInHistory();
if (!isHomeStack() || numActivities() > 0) {
// We want to show the starting preview window if we are
// switching to a new task, or the next activity's process is
// not currently running.
//當(dāng)切換到新的task聊记，或者下一個(gè)activity的進(jìn)程目前并沒(méi)有運(yùn)行撒妈，則執(zhí)行：
boolean showStartingIcon = newTask;
ProcessRecord proc = r.app;
if (proc == null) {
proc = mService.mProcessNames.get(r.processName, r.info.applicationInfo.uid);
}
if (proc == null || proc.thread == null) {
showStartingIcon = true;
}
if (DEBUG_TRANSITION) Slog.v(TAG_TRANSITION,
"Prepare open transition: starting " + r);
if ((r.intent.getFlags() & Intent.FLAG_ACTIVITY_NO_ANIMATION) != 0) {
mWindowManager.prepareAppTransition(AppTransition.TRANSIT_NONE, keepCurTransition);
mNoAnimActivities.add(r);
} else {
mWindowManager.prepareAppTransition(newTask
? r.mLaunchTaskBehind
? AppTransition.TRANSIT_TASK_OPEN_BEHIND
: AppTransition.TRANSIT_TASK_OPEN
: AppTransition.TRANSIT_ACTIVITY_OPEN, keepCurTransition);
mNoAnimActivities.remove(r);
}
mWindowManager.addAppToken(task.mActivities.indexOf(r),
r.appToken, r.task.taskId, mStackId, r.info.screenOrientation, r.fullscreen,
(r.info.flags & ActivityInfo.FLAG_SHOW_FOR_ALL_USERS) != 0, r.userId,
r.info.configChanges, task.voiceSession != null, r.mLaunchTaskBehind);
boolean doShow = true;
if (newTask) {
// Even though this activity is starting fresh, we still need
// to reset it to make sure we apply affinities to move any
// existing activities from other tasks in to it.
// If the caller has requested that the target task be
// reset, then do so.
if ((r.intent.getFlags() & Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED) != 0) {
resetTaskIfNeededLocked(r, r);
doShow = topRunningNonDelayedActivityLocked(null) == r;
}
} else if (options != null && new ActivityOptions(options).getAnimationType()
== ActivityOptions.ANIM_SCENE_TRANSITION) {
doShow = false;
}
if (r.mLaunchTaskBehind) {
// Don't do a starting window for mLaunchTaskBehind. More importantly make sure we
// tell WindowManager that r is visible even though it is at the back of the stack.
mWindowManager.setAppVisibility(r.appToken, true);
ensureActivitiesVisibleLocked(null, 0);
} else if (SHOW_APP_STARTING_PREVIEW && doShow) {
// Figure out if we are transitioning from another activity that is
// "has the same starting icon" as the next one. This allows the
// window manager to keep the previous window it had previously
// created, if it still had one.
ActivityRecord prev = mResumedActivity;
if (prev != null) {
// We don't want to reuse the previous starting preview if:
// (1) The current activity is in a different task.
if (prev.task != r.task) {
prev = null;
}
// (2) The current activity is already displayed.
else if (prev.nowVisible) {
prev = null;
}
}
mWindowManager.setAppStartingWindow(
r.appToken, r.packageName, r.theme,
mService.compatibilityInfoForPackageLocked(
r.info.applicationInfo), r.nonLocalizedLabel,
r.labelRes, r.icon, r.logo, r.windowFlags,
prev != null ? prev.appToken : null, showStartingIcon);
r.mStartingWindowShown = true;
}
} else {
// If this is the first activity, don't do any fancy animations,
// because there is nothing for it to animate on top of.
mWindowManager.addAppToken(task.mActivities.indexOf(r), r.appToken,
r.task.taskId, mStackId, r.info.screenOrientation, r.fullscreen,
(r.info.flags & ActivityInfo.FLAG_SHOW_FOR_ALL_USERS) != 0, r.userId,
r.info.configChanges, task.voiceSession != null, r.mLaunchTaskBehind);
ActivityOptions.abort(options);
options = null;
}
if (VALIDATE_TOKENS) {
validateAppTokensLocked();
}
if (doResume) {
mStackSupervisor.resumeTopActivitiesLocked(this, r, options);
}
}
上述函數(shù)中，注意這一句:for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {這個(gè)mTaskHistory.size()是什么呢排监？還記得我們?cè)诘谝还?jié)中的這張圖嗎?
記得我們?cè)谇懊嬲f(shuō)過(guò):AMS提供了一個(gè)ArrayList mHistory來(lái)管理所有的activity,同樣的狰右，這里的mTaskHistory.size()表示的是系統(tǒng)中歷史任務(wù)的個(gè)數(shù)，因?yàn)長(zhǎng)auncher已經(jīng)運(yùn)行起來(lái)了舆床，所以此處mTaskHistory.size()的值大于0.
????同時(shí)這個(gè)方法中還進(jìn)行了WindowManagerService的一系列操作棋蚌，也就是通過(guò)mWindowManager這個(gè)對(duì)象來(lái)準(zhǔn)備一系列的新老Activity組件的切換工作。
????如果參數(shù)doResume的值為true,表示這個(gè)要啟動(dòng)并且在任務(wù)棧頂部的的Activity已經(jīng)進(jìn)入Resume狀態(tài)了挨队，那么接著進(jìn)行resumeTopActivitiesLocked(this, r, options)方法:
boolean resumeTopActivitiesLocked(ActivityStack targetStack, ActivityRecord target,
Bundle targetOptions) {
if (targetStack == null) {
targetStack = mFocusedStack;
}
// Do targetStack first.
boolean result = false;
if (isFrontStack(targetStack)) {
result = targetStack.resumeTopActivityLocked(target, targetOptions);
}
for (int displayNdx = mActivityDisplays.size() - 1; displayNdx >= 0; --displayNdx) {
final ArrayList<ActivityStack> stacks = mActivityDisplays.valueAt(displayNdx).mStacks;
for (int stackNdx = stacks.size() - 1; stackNdx >= 0; --stackNdx) {
final ActivityStack stack = stacks.get(stackNdx);
if (stack == targetStack) {
// Already started above.
//上面已經(jīng)啟動(dòng)
continue;
}
if (isFrontStack(stack)) {
stack.resumeTopActivityLocked(null);
}
}
}
return result;
}
調(diào)用了resumeTopActivityLocked(target, targetOptions);:
final boolean resumeTopActivityLocked(ActivityRecord prev, Bundle options) {
if (mStackSupervisor.inResumeTopActivity) {
// Don't even start recursing.
return false;
}
boolean result = false;
try {
// Protect against recursion.
mStackSupervisor.inResumeTopActivity = true;
if (mService.mLockScreenShown == ActivityManagerService.LOCK_SCREEN_LEAVING) {
mService.mLockScreenShown = ActivityManagerService.LOCK_SCREEN_HIDDEN;
mService.updateSleepIfNeededLocked();
}
result = resumeTopActivityInnerLocked(prev, options);
} finally {
mStackSupervisor.inResumeTopActivity = false;
}
return result;
}
調(diào)用了resumeTopActivityInnerLocked(prev, options):
private boolean resumeTopActivityInnerLocked(ActivityRecord prev, Bundle options) {
......
// Find the first activity that is not finishing.
//找出還沒(méi)結(jié)束的首個(gè)ActivityRecord
final ActivityRecord next = topRunningActivityLocked(null);
// Remember how we'll process this pause/resume situation, and ensure
// that the state is reset however we wind up proceeding.
final boolean userLeaving = mStackSupervisor.mUserLeaving;
mStackSupervisor.mUserLeaving = false;
final TaskRecord prevTask = prev != null ? prev.task : null;
//如果一個(gè)沒(méi)結(jié)束的Activity都沒(méi)有(所有Activity都結(jié)束了)谷暮，就開(kāi)啟Launcher程序
if (next == null) {
// There are no more activities!
final String reason = "noMoreActivities";
if (!mFullscreen) {
// Try to move focus to the next visible stack with a running activity if this
// stack is not covering the entire screen.
final ActivityStack stack = getNextVisibleStackLocked();
if (adjustFocusToNextVisibleStackLocked(stack, reason)) {
return mStackSupervisor.resumeTopActivitiesLocked(stack, prev, null);
}
}
// Let's just start up the Launcher...
ActivityOptions.abort(options);
if (DEBUG_STATES) Slog.d(TAG_STATES,
"resumeTopActivityLocked: No more activities go home");
if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
// Only resume home if on home display
final int returnTaskType = prevTask == null || !prevTask.isOverHomeStack() ?
HOME_ACTIVITY_TYPE : prevTask.getTaskToReturnTo();
return isOnHomeDisplay() &&
mStackSupervisor.resumeHomeStackTask(returnTaskType, prev, reason);
}
......
// We need to start pausing the current activity so the top one
// can be resumed...
boolean dontWaitForPause = (next.info.flags&ActivityInfo.FLAG_RESUME_WHILE_PAUSING) != 0;
boolean pausing = mStackSupervisor.pauseBackStacks(userLeaving, true, dontWaitForPause);
//先需要暫停當(dāng)前的Activity。因?yàn)槲覀兪窃贚ancher中啟動(dòng)mainActivity盛垦，所以當(dāng)前mResumedActivity湿弦！=null，
//調(diào)用startPausingLocked()使得Launcher進(jìn)入Pausing狀態(tài)
if (mResumedActivity != null) {
if (DEBUG_STATES) Slog.d(TAG_STATES,
"resumeTopActivityLocked: Pausing " + mResumedActivity);
pausing |= startPausingLocked(userLeaving, false, true, dontWaitForPause);
}
......
if (prev != null && prev != next) {
if (!mStackSupervisor.mWaitingVisibleActivities.contains(prev)
&& next != null && !next.nowVisible) {
mStackSupervisor.mWaitingVisibleActivities.add(prev);
if (DEBUG_SWITCH) Slog.v(TAG_SWITCH,
"Resuming top, waiting visible to hide: " + prev);
} else {
// The next activity is already visible, so hide the previous
// activity's windows right now so we can show the new one ASAP.
// We only do this if the previous is finishing, which should mean
// it is on top of the one being resumed so hiding it quickly
// is good. Otherwise, we want to do the normal route of allowing
// the resumed activity to be shown so we can decide if the
// previous should actually be hidden depending on whether the
// new one is found to be full-screen or not.
//注意這個(gè)大段的注釋情臭，到這里是mWindowManager真正開(kāi)始啟動(dòng)下一個(gè)Activity組件的過(guò)程。
if (prev.finishing) {
mWindowManager.setAppVisibility(prev.appToken, false);
if (DEBUG_SWITCH) Slog.v(TAG_SWITCH,
"Not waiting for visible to hide: " + prev + ", waitingVisible="
+ mStackSupervisor.mWaitingVisibleActivities.contains(prev)
+ ", nowVisible=" + next.nowVisible);
} else {
if (DEBUG_SWITCH) Slog.v(TAG_SWITCH,
"Previous already visible but still waiting to hide: " + prev
+ ", waitingVisible="
+ mStackSupervisor.mWaitingVisibleActivities.contains(prev)
+ ", nowVisible=" + next.nowVisible);
}
}
}
// Launching this app's activity, make sure the app is no longer
// considered stopped.
//啟動(dòng)app的Activity,確保這個(gè)App不再會(huì)掛掉赌蔑。
try {
AppGlobals.getPackageManager().setPackageStoppedState(
next.packageName, false, next.userId); /* TODO: Verify if correct userid */
} catch (RemoteException e1) {
} catch (IllegalArgumentException e) {
Slog.w(TAG, "Failed trying to unstop package "
+ next.packageName + ": " + e);
}
......
ActivityStack lastStack = mStackSupervisor.getLastStack();
//進(jìn)程已存在的情況
if (next.app != null && next.app.thread != null) {
if (DEBUG_SWITCH) Slog.v(TAG_SWITCH, "Resume running: " + next);
// This activity is now becoming visible.
mWindowManager.setAppVisibility(next.appToken, true);
// schedule launch ticks to collect information about slow apps.
next.startLaunchTickingLocked();
ActivityRecord lastResumedActivity =
lastStack == null ? null :lastStack.mResumedActivity;
ActivityState lastState = next.state;
mService.updateCpuStats();
if (DEBUG_STATES) Slog.v(TAG_STATES, "Moving to RESUMED: " + next + " (in existing)");
//設(shè)置Activity狀態(tài)為resumed
next.state = ActivityState.RESUMED;
mResumedActivity = next;
next.task.touchActiveTime();
mRecentTasks.addLocked(next.task);
mService.updateLruProcessLocked(next.app, true, null);
updateLRUListLocked(next);
mService.updateOomAdjLocked();
// Have the window manager re-evaluate the orientation of
// the screen based on the new activity order.
boolean notUpdated = true;
if (mStackSupervisor.isFrontStack(this)) {
Configuration config = mWindowManager.updateOrientationFromAppTokens(
mService.mConfiguration,
next.mayFreezeScreenLocked(next.app) ? next.appToken : null);
if (config != null) {
next.frozenBeforeDestroy = true;
}
notUpdated = !mService.updateConfigurationLocked(config, next, false, false);
}
if (notUpdated) {
// The configuration update wasn't able to keep the existing
// instance of the activity, and instead started a new one.
// We should be all done, but let's just make sure our activity
// is still at the top and schedule another run if something
// weird happened.
ActivityRecord nextNext = topRunningActivityLocked(null);
if (DEBUG_SWITCH || DEBUG_STATES) Slog.i(TAG_STATES,
"Activity config changed during resume: " + next
+ ", new next: " + nextNext);
if (nextNext != next) {
// Do over!
mStackSupervisor.scheduleResumeTopActivities();
}
if (mStackSupervisor.reportResumedActivityLocked(next)) {
mNoAnimActivities.clear();
if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
return true;
}
if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
return false;
}
try {
// Deliver all pending results.
ArrayList<ResultInfo> a = next.results;
if (a != null) {
final int N = a.size();
if (!next.finishing && N > 0) {
if (DEBUG_RESULTS) Slog.v(TAG_RESULTS,
"Delivering results to " + next + ": " + a);
next.app.thread.scheduleSendResult(next.appToken, a);
}
}
if (next.newIntents != null) {
next.app.thread.scheduleNewIntent(next.newIntents, next.appToken);
}
EventLog.writeEvent(EventLogTags.AM_RESUME_ACTIVITY, next.userId,
System.identityHashCode(next), next.task.taskId, next.shortComponentName);
next.sleeping = false;
mService.showAskCompatModeDialogLocked(next);
next.app.pendingUiClean = true;
next.app.forceProcessStateUpTo(mService.mTopProcessState);
next.clearOptionsLocked();
next.app.thread.scheduleResumeActivity(next.appToken, next.app.repProcState,
mService.isNextTransitionForward(), resumeAnimOptions);
mStackSupervisor.checkReadyForSleepLocked();
if (DEBUG_STATES) Slog.d(TAG_STATES, "resumeTopActivityLocked: Resumed " + next);
} catch (Exception e) {
// Whoops, need to restart this activity!
if (DEBUG_STATES) Slog.v(TAG_STATES, "Resume failed; resetting state to "
+ lastState + ": " + next);
next.state = lastState;
if (lastStack != null) {
lastStack.mResumedActivity = lastResumedActivity;
}
Slog.i(TAG, "Restarting because process died: " + next);
if (!next.hasBeenLaunched) {
next.hasBeenLaunched = true;
} else if (SHOW_APP_STARTING_PREVIEW && lastStack != null &&
mStackSupervisor.isFrontStack(lastStack)) {
mWindowManager.setAppStartingWindow(
next.appToken, next.packageName, next.theme,
mService.compatibilityInfoForPackageLocked(next.info.applicationInfo),
next.nonLocalizedLabel, next.labelRes, next.icon, next.logo,
next.windowFlags, null, true);
}
mStackSupervisor.startSpecificActivityLocked(next, true, false);
if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
return true;
}
總結(jié)一下該函數(shù)要功能:
- 首先調(diào)用topRunningActivityLocked(null)獲得堆棧頂端剛創(chuàng)建的Activity:App的MainActivity(即在startActivityUncheckedLocked()中創(chuàng)建的那個(gè)),并保存在next中俯在。然后把mUserLeaving值保存在本地變量userLeaving中，并重新設(shè)置為flase娃惯。
- 當(dāng)找不到需要resume的Activity跷乐，則直接回到桌面(閃退);否則，當(dāng)mResumedActivity不為空趾浅，這個(gè)時(shí)候啟動(dòng)新的就要暫停原來(lái)的愕提，則執(zhí)行startPausingLocked()暫停該activity
pausing |= startPausingLocked(userLeaving, false, true, dontWaitForPause);因?yàn)榇藭r(shí)我們是通過(guò)Launcher啟動(dòng)App,所以此時(shí)是在Lancher進(jìn)程中消息傳遞，調(diào)用ActivityThread.handlePauseActivity()皿哨，最終調(diào)用ActivityThread.performPauseActivity()暫停指定Activity(也就是最終這個(gè)Launcher通過(guò)Binder告訴AMS浅侨，它已經(jīng)進(jìn)入Paused狀態(tài)，我要退場(chǎng)了Ｖづ颉Ｈ缡洹！！)不见。接著通過(guò)前面所說(shuō)的Binder通信澳化，通知AMS已經(jīng)完成暫停的操作(對(duì)于這個(gè)方法中的源碼我們暫時(shí)不做深究)。 - WindowManagerService真正開(kāi)始顯示將要啟動(dòng)的Activity的工作稳吮。
- 進(jìn)入startSpecificActivityLocked環(huán)節(jié),AMS創(chuàng)建一個(gè)新的進(jìn)程缎谷，用來(lái)啟動(dòng)一個(gè)ActivityThread實(shí)例，即將要啟動(dòng)的Activity就是在這個(gè)ActivityThread實(shí)例中運(yùn)行:
void startSpecificActivityLocked(ActivityRecord r,
boolean andResume, boolean checkConfig) {
// Is this activity's application already running?
ProcessRecord app = mService.getProcessRecordLocked(r.processName,
r.info.applicationInfo.uid, true);
r.task.stack.setLaunchTime(r);
if (app != null && app.thread != null) {
try {
if ((r.info.flags&ActivityInfo.FLAG_MULTIPROCESS) == 0
|| !"android".equals(r.info.packageName)) {
// Don't add this if it is a platform component that is marked
// to run in multiple processes, because this is actually
// part of the framework so doesn't make sense to track as a
// separate apk in the process.
app.addPackage(r.info.packageName, r.info.applicationInfo.versionCode,
mService.mProcessStats);
}
//真正的啟動(dòng)Activity
realStartActivityLocked(r, app, andResume, checkConfig);
return;
} catch (RemoteException e) {
Slog.w(TAG, "Exception when starting activity "
+ r.intent.getComponent().flattenToShortString(), e);
}
// If a dead object exception was thrown -- fall through to
// restart the application.
}
////當(dāng)進(jìn)程不存在則創(chuàng)建進(jìn)程
mService.startProcessLocked(r.processName, r.info.applicationInfo, true, 0,
"activity", r.intent.getComponent(), false, false, true);
}
調(diào)用了realStartActivityLocked(r, app, andResume, checkConfig);看名字也看得出來(lái)灶似，這是真正啟動(dòng)Aactivity的地方:
final boolean realStartActivityLocked(ActivityRecord r,
ProcessRecord app, boolean andResume, boolean checkConfig)
throws RemoteException {
if (andResume) {
r.startFreezingScreenLocked(app, 0);
mWindowManager.setAppVisibility(r.appToken, true);
// schedule launch ticks to collect information about slow apps.
r.startLaunchTickingLocked();
}
// Have the window manager re-evaluate the orientation of
// the screen based on the new activity order. Note that
// as a result of this, it can call back into the activity
// manager with a new orientation. We don't care about that,
// because the activity is not currently running so we are
// just restarting it anyway.
if (checkConfig) {
Configuration config = mWindowManager.updateOrientationFromAppTokens(
mService.mConfiguration,
r.mayFreezeScreenLocked(app) ? r.appToken : null);
mService.updateConfigurationLocked(config, r, false, false);
}
r.app = app;
app.waitingToKill = null;
r.launchCount++;
r.lastLaunchTime = SystemClock.uptimeMillis();
if (DEBUG_ALL) Slog.v(TAG, "Launching: " + r);
int idx = app.activities.indexOf(r);
if (idx < 0) {
app.activities.add(r);
}
mService.updateLruProcessLocked(app, true, null);
mService.updateOomAdjLocked();
final TaskRecord task = r.task;
if (task.mLockTaskAuth == LOCK_TASK_AUTH_LAUNCHABLE ||
task.mLockTaskAuth == LOCK_TASK_AUTH_LAUNCHABLE_PRIV) {
setLockTaskModeLocked(task, LOCK_TASK_MODE_LOCKED, "mLockTaskAuth==LAUNCHABLE", false);
}
final ActivityStack stack = task.stack;
try {
if (app.thread == null) {
throw new RemoteException();
}
List<ResultInfo> results = null;
List<ReferrerIntent> newIntents = null;
if (andResume) {
results = r.results;
newIntents = r.newIntents;
}
if (DEBUG_SWITCH) Slog.v(TAG_SWITCH,
"Launching: " + r + " icicle=" + r.icicle + " with results=" + results
+ " newIntents=" + newIntents + " andResume=" + andResume);
if (andResume) {
EventLog.writeEvent(EventLogTags.AM_RESTART_ACTIVITY,
r.userId, System.identityHashCode(r),
task.taskId, r.shortComponentName);
}
if (r.isHomeActivity() && r.isNotResolverActivity()) {
// Home process is the root process of the task.
mService.mHomeProcess = task.mActivities.get(0).app;
}
mService.ensurePackageDexOpt(r.intent.getComponent().getPackageName());
r.sleeping = false;
r.forceNewConfig = false;
mService.showAskCompatModeDialogLocked(r);
r.compat = mService.compatibilityInfoForPackageLocked(r.info.applicationInfo);
ProfilerInfo profilerInfo = null;
if (mService.mProfileApp != null && mService.mProfileApp.equals(app.processName)) {
if (mService.mProfileProc == null || mService.mProfileProc == app) {
mService.mProfileProc = app;
final String profileFile = mService.mProfileFile;
if (profileFile != null) {
ParcelFileDescriptor profileFd = mService.mProfileFd;
if (profileFd != null) {
try {
profileFd = profileFd.dup();
} catch (IOException e) {
if (profileFd != null) {
try {
profileFd.close();
} catch (IOException o) {
}
profileFd = null;
}
}
}
profilerInfo = new ProfilerInfo(profileFile, profileFd,
mService.mSamplingInterval, mService.mAutoStopProfiler);
}
}
}
if (andResume) {
app.hasShownUi = true;
app.pendingUiClean = true;
}
app.forceProcessStateUpTo(mService.mTopProcessState);
app.thread.scheduleLaunchActivity(new Intent(r.intent), r.appToken,
System.identityHashCode(r), r.info, new Configuration(mService.mConfiguration),
new Configuration(stack.mOverrideConfig), r.compat, r.launchedFromPackage,
task.voiceInteractor, app.repProcState, r.icicle, r.persistentState, results,
newIntents, !andResume, mService.isNextTransitionForward(), profilerInfo);
if ((app.info.privateFlags&ApplicationInfo.PRIVATE_FLAG_CANT_SAVE_STATE) != 0) {
// This may be a heavy-weight process! Note that the package
// manager will ensure that only activity can run in the main
// process of the .apk, which is the only thing that will be
// considered heavy-weight.
if (app.processName.equals(app.info.packageName)) {
if (mService.mHeavyWeightProcess != null
&& mService.mHeavyWeightProcess != app) {
Slog.w(TAG, "Starting new heavy weight process " + app
+ " when already running "
+ mService.mHeavyWeightProcess);
}
mService.mHeavyWeightProcess = app;
Message msg = mService.mHandler.obtainMessage(
ActivityManagerService.POST_HEAVY_NOTIFICATION_MSG);
msg.obj = r;
mService.mHandler.sendMessage(msg);
}
}
} catch (RemoteException e) {
if (r.launchFailed) {
// This is the second time we failed -- finish activity
// and give up.
Slog.e(TAG, "Second failure launching "
+ r.intent.getComponent().flattenToShortString()
+ ", giving up", e);
mService.appDiedLocked(app);
stack.requestFinishActivityLocked(r.appToken, Activity.RESULT_CANCELED, null,
"2nd-crash", false);
return false;
}
// This is the first time we failed -- restart process and
// retry.
app.activities.remove(r);
throw e;
}
r.launchFailed = false;
if (stack.updateLRUListLocked(r)) {
Slog.w(TAG, "Activity " + r
+ " being launched, but already in LRU list");
}
if (andResume) {
// As part of the process of launching, ActivityThread also performs
// a resume.
stack.minimalResumeActivityLocked(r);
} else {
// This activity is not starting in the resumed state... which
// should look like we asked it to pause+stop (but remain visible),
// and it has done so and reported back the current icicle and
// other state.
if (DEBUG_STATES) Slog.v(TAG_STATES,
"Moving to STOPPED: " + r + " (starting in stopped state)");
r.state = STOPPED;
r.stopped = true;
}
// Launch the new version setup screen if needed. We do this -after-
// launching the initial activity (that is, home), so that it can have
// a chance to initialize itself while in the background, making the
// switch back to it faster and look better.
if (isFrontStack(stack)) {
mService.startSetupActivityLocked();
}
// Update any services we are bound to that might care about whether
// their client may have activities.
mService.mServices.updateServiceConnectionActivitiesLocked(r.app);
return true;
}
掉用了app.thread.scheduleLaunchActivity(new Intent(r.intent), r.appToken, System.identityHashCode(r), r.info, new Configuration(mService.mConfiguration), new Configuration(stack.mOverrideConfig), r.compat, r.launchedFromPackage, task.voiceInteractor, app.repProcState, r.icicle, r.persistentState, results, newIntents, !andResume, mService.isNextTransitionForward(), profilerInfo);
這里的app.thread是IApplicationThread接口的對(duì)象列林，而真正首先這個(gè)接口的地方在ApplicationThreadNative類(lèi)中的內(nèi)部類(lèi)ApplicationThreadProxy中。這段如果讀者看過(guò)源碼的話肯定會(huì)發(fā)現(xiàn)喻奥，這個(gè)接口的實(shí)現(xiàn)方式以及類(lèi)的代碼結(jié)構(gòu)和我們呢在上一章中ActivityManagerNative類(lèi)部分如出一轍ＯΑ！撞蚕！
我們接著看:
public final void scheduleLaunchActivity(Intent intent, IBinder token, int ident,
ActivityInfo info, Configuration curConfig, Configuration overrideConfig,
CompatibilityInfo compatInfo, String referrer, IVoiceInteractor voiceInteractor,
int procState, Bundle state, PersistableBundle persistentState,
List<ResultInfo> pendingResults, List<ReferrerIntent> pendingNewIntents,
boolean notResumed, boolean isForward, ProfilerInfo profilerInfo) throws RemoteException {
Parcel data = Parcel.obtain();
data.writeInterfaceToken(IApplicationThread.descriptor);
intent.writeToParcel(data, 0);
data.writeStrongBinder(token);
data.writeInt(ident);
info.writeToParcel(data, 0);
curConfig.writeToParcel(data, 0);
if (overrideConfig != null) {
data.writeInt(1);
overrideConfig.writeToParcel(data, 0);
} else {
data.writeInt(0);
}
compatInfo.writeToParcel(data, 0);
data.writeString(referrer);
data.writeStrongBinder(voiceInteractor != null ? voiceInteractor.asBinder() : null);
data.writeInt(procState);
data.writeBundle(state);
data.writePersistableBundle(persistentState);
data.writeTypedList(pendingResults);
data.writeTypedList(pendingNewIntents);
data.writeInt(notResumed ? 1 : 0);
data.writeInt(isForward ? 1 : 0);
if (profilerInfo != null) {
data.writeInt(1);
profilerInfo.writeToParcel(data, Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
} else {
data.writeInt(0);
}
mRemote.transact(SCHEDULE_LAUNCH_ACTIVITY_TRANSACTION, data, null,
IBinder.FLAG_ONEWAY);
data.recycle();
}
這里又復(fù)用了IBinder的mRemote.transact(SCHEDULE_LAUNCH_ACTIVITY_TRANSACTION, data, null, IBinder.FLAG_ONEWAY);接口润梯，想起來(lái)沒(méi)？上一章是不是有過(guò)類(lèi)似的體驗(yàn)吧谩纺铭？如果我們往上找的花就會(huì)發(fā)現(xiàn)有一個(gè)重寫(xiě)的onTransact()方法，就是他了:
@Override
public boolean onTransact(int code, Parcel data, Parcel reply, int flags)
throws RemoteException {
switch (code) {
case SCHEDULE_PAUSE_ACTIVITY_TRANSACTION:
{
data.enforceInterface(IApplicationThread.descriptor);
IBinder b = data.readStrongBinder();
boolean finished = data.readInt() != 0;
boolean userLeaving = data.readInt() != 0;
int configChanges = data.readInt();
boolean dontReport = data.readInt() != 0;
schedulePauseActivity(b, finished, userLeaving, configChanges, dontReport);
return true;
}
case SCHEDULE_STOP_ACTIVITY_TRANSACTION:
{
data.enforceInterface(IApplicationThread.descriptor);
IBinder b = data.readStrongBinder();
boolean show = data.readInt() != 0;
int configChanges = data.readInt();
scheduleStopActivity(b, show, configChanges);
return true;
}
case SCHEDULE_WINDOW_VISIBILITY_TRANSACTION:
{
data.enforceInterface(IApplicationThread.descriptor);
IBinder b = data.readStrongBinder();
boolean show = data.readInt() != 0;
scheduleWindowVisibility(b, show);
return true;
}
......
case SCHEDULE_LAUNCH_ACTIVITY_TRANSACTION:
{
data.enforceInterface(IApplicationThread.descriptor);
Intent intent = Intent.CREATOR.createFromParcel(data);
IBinder b = data.readStrongBinder();
int ident = data.readInt();
ActivityInfo info = ActivityInfo.CREATOR.createFromParcel(data);
Configuration curConfig = Configuration.CREATOR.createFromParcel(data);
Configuration overrideConfig = null;
if (data.readInt() != 0) {
overrideConfig = Configuration.CREATOR.createFromParcel(data);
}
CompatibilityInfo compatInfo = CompatibilityInfo.CREATOR.createFromParcel(data);
String referrer = data.readString();
IVoiceInteractor voiceInteractor = IVoiceInteractor.Stub.asInterface(
data.readStrongBinder());
int procState = data.readInt();
Bundle state = data.readBundle();
PersistableBundle persistentState = data.readPersistableBundle();
List<ResultInfo> ri = data.createTypedArrayList(ResultInfo.CREATOR);
List<ReferrerIntent> pi = data.createTypedArrayList(ReferrerIntent.CREATOR);
boolean notResumed = data.readInt() != 0;
boolean isForward = data.readInt() != 0;
ProfilerInfo profilerInfo = data.readInt() != 0
? ProfilerInfo.CREATOR.createFromParcel(data) : null;
scheduleLaunchActivity(intent, b, ident, info, curConfig, overrideConfig, compatInfo,
referrer, voiceInteractor, procState, state, persistentState, ri, pi,
notResumed, isForward, profilerInfo);
return true;
}
......
調(diào)用了scheduleLaunchActivity(intent, b, ident, info, curConfig, overrideConfig, compatInfo, referrer, voiceInteractor, procState, state, persistentState, ri, pi, notResumed, isForward, profilerInfo);注意這其實(shí)也是IApplication接口中封裝的一個(gè)方法刀疙，而真正實(shí)現(xiàn)這個(gè)方法的類(lèi)是 ActiivtyThread類(lèi)中的ApplicationThread類(lèi)舶赔。我們來(lái)看看這個(gè)方法都干了什么:
// we use token to identify this activity without having to send the
// activity itself back to the activity manager. (matters more with ipc)
@Override
public final void scheduleLaunchActivity(Intent intent, IBinder token, int ident,
ActivityInfo info, Configuration curConfig, Configuration overrideConfig,
CompatibilityInfo compatInfo, String referrer, IVoiceInteractor voiceInteractor,
int procState, Bundle state, PersistableBundle persistentState,
List<ResultInfo> pendingResults, List<ReferrerIntent> pendingNewIntents,
boolean notResumed, boolean isForward, ProfilerInfo profilerInfo) {
updateProcessState(procState, false);
ActivityClientRecord r = new ActivityClientRecord();
r.token = token;
r.ident = ident;
r.intent = intent;
r.referrer = referrer;
r.voiceInteractor = voiceInteractor;
r.activityInfo = info;
r.compatInfo = compatInfo;
r.state = state;
r.persistentState = persistentState;
r.pendingResults = pendingResults;
r.pendingIntents = pendingNewIntents;
r.startsNotResumed = notResumed;
r.isForward = isForward;
r.profilerInfo = profilerInfo;
r.overrideConfig = overrideConfig;
updatePendingConfiguration(curConfig);
sendMessage(H.LAUNCH_ACTIVITY, r);
}
可以看到這里掉用了sendMessage(H.LAUNCH_ACTIVITY, r)方法,用handle來(lái)發(fā)送消息:
public void handleMessage(Message msg) {
if (DEBUG_MESSAGES) Slog.v(TAG, ">>> handling: " + codeToString(msg.what));
switch (msg.what) {
case LAUNCH_ACTIVITY: {
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityStart");
final ActivityClientRecord r = (ActivityClientRecord) msg.obj;
r.packageInfo = getPackageInfoNoCheck(
r.activityInfo.applicationInfo, r.compatInfo);
handleLaunchActivity(r, null);
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
} break;
調(diào)用了andleLaunchActivity(r, null);
private void handleLaunchActivity(ActivityClientRecord r, Intent customIntent) {
// If we are getting ready to gc after going to the background, well
// we are back active so skip it.
unscheduleGcIdler();
mSomeActivitiesChanged = true;
if (r.profilerInfo != null) {
mProfiler.setProfiler(r.profilerInfo);
mProfiler.startProfiling();
}
// Make sure we are running with the most recent config.
handleConfigurationChanged(null, null);
if (localLOGV) Slog.v(
TAG, "Handling launch of " + r);
// Initialize before creating the activity
WindowManagerGlobal.initialize();
Activity a = performLaunchActivity(r, customIntent);
if (a != null) {
r.createdConfig = new Configuration(mConfiguration);
Bundle oldState = r.state;
handleResumeActivity(r.token, false, r.isForward,
!r.activity.mFinished && !r.startsNotResumed);
if (!r.activity.mFinished && r.startsNotResumed) {
// The activity manager actually wants this one to start out
// paused, because it needs to be visible but isn't in the
// foreground. We accomplish this by going through the
// normal startup (because activities expect to go through
// onResume() the first time they run, before their window
// is displayed), and then pausing it. However, in this case
// we do -not- need to do the full pause cycle (of freezing
// and such) because the activity manager assumes it can just
// retain the current state it has.
try {
r.activity.mCalled = false;
mInstrumentation.callActivityOnPause(r.activity);
// We need to keep around the original state, in case
// we need to be created again. But we only do this
// for pre-Honeycomb apps, which always save their state
// when pausing, so we can not have them save their state
// when restarting from a paused state. For HC and later,
// we want to (and can) let the state be saved as the normal
// part of stopping the activity.
if (r.isPreHoneycomb()) {
r.state = oldState;
}
if (!r.activity.mCalled) {
throw new SuperNotCalledException(
"Activity " + r.intent.getComponent().toShortString() +
" did not call through to super.onPause()");
}
} catch (SuperNotCalledException e) {
throw e;
} catch (Exception e) {
if (!mInstrumentation.onException(r.activity, e)) {
throw new RuntimeException(
"Unable to pause activity "
+ r.intent.getComponent().toShortString()
+ ": " + e.toString(), e);
}
}
r.paused = true;
}
} else {
// If there was an error, for any reason, tell the activity
// manager to stop us.
try {
ActivityManagerNative.getDefault()
.finishActivity(r.token, Activity.RESULT_CANCELED, null, false);
} catch (RemoteException ex) {
// Ignore
}
}
}
調(diào)用了performLaunchActivity()
private Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {
// System.out.println("##### [" + System.currentTimeMillis() + "] ActivityThread.performLaunchActivity(" + r + ")");
ActivityInfo aInfo = r.activityInfo;
if (r.packageInfo == null) {
r.packageInfo = getPackageInfo(aInfo.applicationInfo, r.compatInfo,
Context.CONTEXT_INCLUDE_CODE);
}
ComponentName component = r.intent.getComponent();
if (component == null) {
component = r.intent.resolveActivity(
mInitialApplication.getPackageManager());
r.intent.setComponent(component);
}
if (r.activityInfo.targetActivity != null) {
component = new ComponentName(r.activityInfo.packageName,
r.activityInfo.targetActivity);
}
Activity activity = null;
try {
java.lang.ClassLoader cl = r.packageInfo.getClassLoader();
activity = mInstrumentation.newActivity(
cl, component.getClassName(), r.intent);
StrictMode.incrementExpectedActivityCount(activity.getClass());
r.intent.setExtrasClassLoader(cl);
r.intent.prepareToEnterProcess();
if (r.state != null) {
r.state.setClassLoader(cl);
}
} catch (Exception e) {
if (!mInstrumentation.onException(activity, e)) {
throw new RuntimeException(
"Unable to instantiate activity " + component
+ ": " + e.toString(), e);
}
}
try {
Application app = r.packageInfo.makeApplication(false, mInstrumentation);
if (localLOGV) Slog.v(TAG, "Performing launch of " + r);
if (localLOGV) Slog.v(
TAG, r + ": app=" + app
+ ", appName=" + app.getPackageName()
+ ", pkg=" + r.packageInfo.getPackageName()
+ ", comp=" + r.intent.getComponent().toShortString()
+ ", dir=" + r.packageInfo.getAppDir());
if (activity != null) {
Context appContext = createBaseContextForActivity(r, activity);
CharSequence title = r.activityInfo.loadLabel(appContext.getPackageManager());
Configuration config = new Configuration(mCompatConfiguration);
if (DEBUG_CONFIGURATION) Slog.v(TAG, "Launching activity "
+ r.activityInfo.name + " with config " + config);
activity.attach(appContext, this, getInstrumentation(), r.token,
r.ident, app, r.intent, r.activityInfo, title, r.parent,
r.embeddedID, r.lastNonConfigurationInstances, config,
r.referrer, r.voiceInteractor);
if (customIntent != null) {
activity.mIntent = customIntent;
}
r.lastNonConfigurationInstances = null;
activity.mStartedActivity = false;
int theme = r.activityInfo.getThemeResource();
if (theme != 0) {
activity.setTheme(theme);
}
activity.mCalled = false;
if (r.isPersistable()) {
mInstrumentation.callActivityOnCreate(activity, r.state, r.persistentState);
} else {
mInstrumentation.callActivityOnCreate(activity, r.state);
}
if (!activity.mCalled) {
throw new SuperNotCalledException(
"Activity " + r.intent.getComponent().toShortString() +
" did not call through to super.onCreate()");
}
r.activity = activity;
r.stopped = true;
if (!r.activity.mFinished) {
activity.performStart();
r.stopped = false;
}
if (!r.activity.mFinished) {
if (r.isPersistable()) {
if (r.state != null || r.persistentState != null) {
mInstrumentation.callActivityOnRestoreInstanceState(activity, r.state,
r.persistentState);
}
} else if (r.state != null) {
mInstrumentation.callActivityOnRestoreInstanceState(activity, r.state);
}
}
if (!r.activity.mFinished) {
activity.mCalled = false;
if (r.isPersistable()) {
mInstrumentation.callActivityOnPostCreate(activity, r.state,
r.persistentState);
} else {
mInstrumentation.callActivityOnPostCreate(activity, r.state);
}
if (!activity.mCalled) {
throw new SuperNotCalledException(
"Activity " + r.intent.getComponent().toShortString() +
" did not call through to super.onPostCreate()");
}
}
}
r.paused = true;
mActivities.put(r.token, r);
} catch (SuperNotCalledException e) {
throw e;
} catch (Exception e) {
if (!mInstrumentation.onException(activity, e)) {
throw new RuntimeException(
"Unable to start activity " + component
+ ": " + e.toString(), e);
}
}
return activity;
}
可以看到這里:
if (r.isPersistable()) {
mInstrumentation.callActivityOnCreate(activity, r.state, r.persistentState);
} else {
mInstrumentation.callActivityOnCreate(activity, r.state);
}
mInstrumentation是Instrumentation類(lèi)的對(duì)象，還記得我們?cè)谥f(shuō)過(guò)這個(gè)類(lèi)時(shí)干嘛的嗎谦秧？他是負(fù)責(zé)操作Activity生命周期的發(fā)那個(gè)類(lèi)竟纳，這里調(diào)用了callActivityOnCreate()方法實(shí)際上就是Activity的onCreat()方法。
