activity的创建
继 上一篇 重温-Application的创建和启动流程（一）之后，我们继续在ActivityManagerService类中的attachApplicationLocked方法往下走
// 查看栈顶可见activity是否正在等待在此进程中运行
if (normalMode) {
try {
//mStackSupervisor 应用的activity栈
if (mStackSupervisor.attachApplicationLocked(app)) {
didSomething = true;
}
} catch (Exception e) {
Slog.wtf(TAG, "Exception thrown launching activities in " + app, e);
badApp = true;
}
}
进入ActivityStackSupervisor类中的attachApplicationLocked方法
boolean attachApplicationLocked(ProcessRecord app) throws RemoteException {
final String processName = app.processName;
boolean didSomething = false;
for (int displayNdx = mActivityDisplays.size() - 1; displayNdx >= 0; --displayNdx) {
final ActivityDisplay display = mActivityDisplays.valueAt(displayNdx);
for (int stackNdx = display.getChildCount() - 1; stackNdx >= 0; --stackNdx) {
final ActivityStack stack = display.getChildAt(stackNdx);
if (!isFocusedStack(stack)) {
continue;
}
//从activityStack（activity栈）把所有的activity添加给 mTmpActivityList
stack.getAllRunningVisibleActivitiesLocked(mTmpActivityList);
//返回的是当前应用activity堆栈最顶端的activity
final ActivityRecord top = stack.topRunningActivityLocked();
final int size = mTmpActivityList.size();
//遍历所以的activity的数据存储类
for (int i = 0; i < size; i++) {
final ActivityRecord activity = mTmpActivityList.get(i);
if (activity.app == null && app.uid == activity.info.applicationInfo.uid
&& processName.equals(activity.processName)) {
try {
if (realStartActivityLocked(activity, app,
top == activity /* andResume */, true /* checkConfig */)) {
didSomething = true;
}
} catch (RemoteException e) {
Slog.w(TAG, "Exception in new application when starting activity "
+ top.intent.getComponent().flattenToShortString(), e);
throw e;
}
}
}
}
}
if (!didSomething) {
ensureActivitiesVisibleLocked(null, 0, !PRESERVE_WINDOWS);
}
return didSomething;
}
进入ActivityStackSupervisor类中的realStartActivityLocked方法
final boolean realStartActivityLocked(ActivityRecord r, ProcessRecord app,
boolean andResume, boolean checkConfig) throws RemoteException {
if (!allPausedActivitiesComplete()) {
if (DEBUG_SWITCH || DEBUG_PAUSE || DEBUG_STATES) Slog.v(TAG_PAUSE,
"realStartActivityLocked: Skipping start of r=" + r
+ " some activities pausing...");
return false;
}
final TaskRecord task = r.getTask();
final ActivityStack stack = task.getStack();
beginDeferResume();
try {
r.startFreezingScreenLocked(app, 0);
r.startLaunchTickingLocked();
r.setProcess(app);
if (getKeyguardController().isKeyguardLocked()) {
r.notifyUnknownVisibilityLaunched();
}
if (checkConfig) {
ensureVisibilityAndConfig(r, r.getDisplayId(),
false /* markFrozenIfConfigChanged */, true /* deferResume */);
}
if (r.getStack().checkKeyguardVisibility(r, true /* shouldBeVisible */,
true /* isTop */)) {
r.setVisibility(true);
}
final int applicationInfoUid =
(r.info.applicationInfo != null) ? r.info.applicationInfo.uid : -1;
if ((r.userId != app.userId) || (r.appInfo.uid != applicationInfoUid)) {
Slog.wtf(TAG,
"User ID for activity changing for " + r
+ " appInfo.uid=" + r.appInfo.uid
+ " info.ai.uid=" + applicationInfoUid
+ " old=" + r.app + " new=" + 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 LockTaskController lockTaskController = mService.getLockTaskController();
if (task.mLockTaskAuth == LOCK_TASK_AUTH_LAUNCHABLE
|| task.mLockTaskAuth == LOCK_TASK_AUTH_LAUNCHABLE_PRIV
|| (task.mLockTaskAuth == LOCK_TASK_AUTH_WHITELISTED
&& lockTaskController.getLockTaskModeState()
== LOCK_TASK_MODE_LOCKED)) {
lockTaskController.startLockTaskMode(task, false, 0 /* blank UID */);
}
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);
EventLog.writeEvent(EventLogTags.AM_RESTART_ACTIVITY, r.userId,
System.identityHashCode(r), task.taskId, r.shortComponentName);
if (r.isActivityTypeHome()) {
mService.mHomeProcess = task.mActivities.get(0).app;
}
mService.notifyPackageUse(r.intent.getComponent().getPackageName(),
PackageManager.NOTIFY_PACKAGE_USE_ACTIVITY);
r.sleeping = false;
r.forceNewConfig = false;
mService.getAppWarningsLocked().onStartActivity(r);
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;
ProfilerInfo profilerInfoSvc = mService.mProfilerInfo;
if (profilerInfoSvc != null && profilerInfoSvc.profileFile != null) {
if (profilerInfoSvc.profileFd != null) {
try {
profilerInfoSvc.profileFd = profilerInfoSvc.profileFd.dup();
} catch (IOException e) {
profilerInfoSvc.closeFd();
}
}
profilerInfo = new ProfilerInfo(profilerInfoSvc);
}
}
}
app.hasShownUi = true;
app.pendingUiClean = true;
app.forceProcessStateUpTo(mService.mTopProcessState);
final MergedConfiguration mergedConfiguration = new MergedConfiguration(
mService.getGlobalConfiguration(), r.getMergedOverrideConfiguration());
r.setLastReportedConfiguration(mergedConfiguration);
logIfTransactionTooLarge(r.intent, r.icicle);
//创建activity启动事务
final ClientTransaction clientTransaction = ClientTransaction.obtain(app.thread,
r.appToken);
//添加回掉（创建了一个LaunchActivityItem） clientTransaction.addCallback(LaunchActivityItem.obtain(new Intent(r.intent),
System.identityHashCode(r), r.info,
mergedConfiguration.getGlobalConfiguration(),
mergedConfiguration.getOverrideConfiguration(), r.compat,
r.launchedFromPackage, task.voiceInteractor, app.repProcState, r.icicle,
r.persistentState, results, newIntents, mService.isNextTransitionForward(),
profilerInfo));
final ActivityLifecycleItem lifecycleItem;
if (andResume) {
lifecycleItem = ResumeActivityItem.obtain(mService.isNextTransitionForward());
} else {
lifecycleItem = PauseActivityItem.obtain();
}
clientTransaction.setLifecycleStateRequest(lifecycleItem);
//提交事务 mService.getLifecycleManager().scheduleTransaction(clientTransaction);
if ((app.info.privateFlags & ApplicationInfo.PRIVATE_FLAG_CANT_SAVE_STATE) != 0
&& mService.mHasHeavyWeightFeature) {
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) {
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;
}
r.launchFailed = true;
app.activities.remove(r);
throw e;
}
} finally {
endDeferResume();
}
r.launchFailed = false;
if (stack.updateLRUListLocked(r)) {
Slog.w(TAG, "Activity " + r + " being launched, but already in LRU list");
}
if (andResume && readyToResume()) {
stack.minimalResumeActivityLocked(r);
} else {
if (DEBUG_STATES) Slog.v(TAG_STATES,
"Moving to PAUSED: " + r + " (starting in paused state)");
r.setState(PAUSED, "realStartActivityLocked");
}
if (isFocusedStack(stack)) {
mService.getActivityStartController().startSetupActivity();
}
if (r.app != null) {
mService.mServices.updateServiceConnectionActivitiesLocked(r.app);
}
return true;
}
进入ClientLifecycleManager类中的scheduleTransaction方法
void scheduleTransaction(ClientTransaction transaction) throws RemoteException {
final IApplicationThread client = transaction.getClient();
transaction.schedule();
if (!(client instanceof Binder)) {
transaction.recycle();
}
}
进入ClientTransaction类中的schedule方法
public void schedule() throws RemoteException {
mClient.scheduleTransaction(this);
}
进入ActicityThread类中中的scheduleTransaction方法
public void scheduleTransaction(ClientTransaction transaction) throws RemoteException {
ActivityThread.this.scheduleTransaction(transaction);
}
进入ActivityThread类的父类ClientTransactionHandler中，调用scheduleTransaction方法
void scheduleTransaction(ClientTransaction transaction) {
transaction.preExecute(this);
//发送一个消息
sendMessage(ActivityThread.H.EXECUTE_TRANSACTION, transaction);
}
进入EXECUTE_TRANSACTION消息的处理逻辑
case EXECUTE_TRANSACTION:
final ClientTransaction transaction = (ClientTransaction) msg.obj;
//mTransactionExecutor是执行事务的对象
mTransactionExecutor.execute(transaction);
if (isSystem()) {
transaction.recycle();
}
break;
进入TransactionExecutor类中的execute方法
public void execute(ClientTransaction transaction) {
final IBinder token = transaction.getActivityToken();
log("Start resolving transaction for client: " + mTransactionHandler + ", token: " + token);
executeCallbacks(transaction);
executeLifecycleState(transaction);
mPendingActions.clear();
}
进入TransactionExecutor类中的executeCallbacks方法
public void executeCallbacks(ClientTransaction transaction) {
final List<ClientTransactionItem> callbacks = transaction.getCallbacks();
if (callbacks == null) {
return;
}
log("Resolving callbacks");
final IBinder token = transaction.getActivityToken();
ActivityClientRecord r = mTransactionHandler.getActivityClient(token);
final ActivityLifecycleItem finalStateRequest = transaction.getLifecycleStateRequest();
final int finalState = finalStateRequest != null ? finalStateRequest.getTargetState()
: UNDEFINED;
final int lastCallbackRequestingState = lastCallbackRequestingState(transaction);
//遍历事务管理器中的所有窗体请求对象
final int size = callbacks.size();
for (int i = 0; i < size; ++i) {
final ClientTransactionItem item = callbacks.get(i);
log("Resolving callback: " + item);
final int postExecutionState = item.getPostExecutionState();
final int closestPreExecutionState = mHelper.getClosestPreExecutionState(r,
item.getPostExecutionState());
if (closestPreExecutionState != UNDEFINED) {
cycleToPath(r, closestPreExecutionState);
}
//进行窗体创建请求
item.execute(mTransactionHandler, token, mPendingActions);
item.postExecute(mTransactionHandler, token, mPendingActions);
if (r == null) {
r = mTransactionHandler.getActivityClient(token);
}
if (postExecutionState != UNDEFINED && r != null) {
final boolean shouldExcludeLastTransition =
i == lastCallbackRequestingState && finalState == postExecutionState;
cycleToPath(r, postExecutionState, shouldExcludeLastTransition);
}
}
}
进入LaunchActivityItem类中的execute方法
public void execute(ClientTransactionHandler client, IBinder token,
PendingTransactionActions pendingActions) {
Trace.traceBegin(TRACE_TAG_ACTIVITY_MANAGER, "activityStart");
//创建一个activityClientRecord对象，用于activity的实例化
ActivityClientRecord r = new ActivityClientRecord(token, mIntent, mIdent, mInfo,
mOverrideConfig, mCompatInfo, mReferrer, mVoiceInteractor, mState, mPersistentState,
mPendingResults, mPendingNewIntents, mIsForward,
mProfilerInfo, client);
//然后回掉给activitythread
client.handleLaunchActivity(r, pendingActions, null /* customIntent */);
Trace.traceEnd(TRACE_TAG_ACTIVITY_MANAGER);
}
进入activitythread类中的handleLaunchActivity方法
public Activity handleLaunchActivity(ActivityClientRecord r,
PendingTransactionActions pendingActions, Intent customIntent) {
unscheduleGcIdler();
mSomeActivitiesChanged = true;
if (r.profilerInfo != null) {
mProfiler.setProfiler(r.profilerInfo);
mProfiler.startProfiling();
}
handleConfigurationChanged(null, null);
if (localLOGV) Slog.v(
TAG, "Handling launch of " + r);
if (!ThreadedRenderer.sRendererDisabled) {
GraphicsEnvironment.earlyInitEGL();
}
WindowManagerGlobal.initialize();
//根据传递过来的activityClientRecord创建一个activity
final Activity a = performLaunchActivity(r, customIntent);
if (a != null) {
r.createdConfig = new Configuration(mConfiguration);
reportSizeConfigurations(r);
if (!r.activity.mFinished && pendingActions != null) {
pendingActions.setOldState(r.state);
pendingActions.setRestoreInstanceState(true);
pendingActions.setCallOnPostCreate(true);
}
} else {
try {
ActivityManager.getService()
.finishActivity(r.token, Activity.RESULT_CANCELED, null,
Activity.DONT_FINISH_TASK_WITH_ACTIVITY);
} catch (RemoteException ex) {
throw ex.rethrowFromSystemServer();
}
}
return a;
}
进入Activitythread类中的performLaunchActivity方法
private Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {
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);
}
ContextImpl appContext = createBaseContextForActivity(r);
Activity activity = null;
try {
//通过反射创建activity对象
java.lang.ClassLoader cl = appContext.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) {
CharSequence title = r.activityInfo.loadLabel(appContext.getPackageManager());
Configuration config = new Configuration(mCompatConfiguration);
if (r.overrideConfig != null) {
config.updateFrom(r.overrideConfig);
}
if (DEBUG_CONFIGURATION) Slog.v(TAG, "Launching activity "
+ r.activityInfo.name + " with config " + config);
Window window = null;
if (r.mPendingRemoveWindow != null && r.mPreserveWindow) {
window = r.mPendingRemoveWindow;
r.mPendingRemoveWindow = null;
r.mPendingRemoveWindowManager = null;
}
appContext.setOuterContext(activity);
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, window, r.configCallback);
if (customIntent != null) {
activity.mIntent = customIntent;
}
r.lastNonConfigurationInstances = null;
checkAndBlockForNetworkAccess();
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.setState(ON_CREATE);
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;
}
进入Instrumentation类中的newActivity方法
public Activity newActivity(ClassLoader cl, String className,
Intent intent)
throws InstantiationException, IllegalAccessException,
ClassNotFoundException {
String pkg = intent != null && intent.getComponent() != null
? intent.getComponent().getPackageName() : null;
return getFactory(pkg).instantiateActivity(cl, className, intent);
}
public @NonNull Activity instantiateActivity(@NonNull ClassLoader cl, @NonNull String className,
@Nullable Intent intent)
throws InstantiationException, IllegalAccessException, ClassNotFoundException {
return (Activity) cl.loadClass(className).newInstance();
}
activity的启动
再次回到ActivityThread类中的performLaunchActivity方法
if (r.isPersistable()) {
//通过mInstrumentation调用activity的生命周期的方法
mInstrumentation.callActivityOnCreate(activity, r.state, r.persistentState);
} else {
mInstrumentation.callActivityOnCreate(activity, r.state);
}
进入Instrumentation类中的callActivityOnCreate方法
public void callActivityOnCreate(Activity activity, Bundle icicle,
PersistableBundle persistentState) {
prePerformCreate(activity);
activity.performCreate(icicle, persistentState);
postPerformCreate(activity);
}
进入activity类中的performCreate方法
final void performCreate(Bundle icicle) {
performCreate(icicle, null);
}
final void performCreate(Bundle icicle, PersistableBundle persistentState) {
mCanEnterPictureInPicture = true;
restoreHasCurrentPermissionRequest(icicle);
if (persistentState != null) {
onCreate(icicle, persistentState);
} else {
onCreate(icicle);
}
writeEventLog(LOG_AM_ON_CREATE_CALLED, "performCreate");
mActivityTransitionState.readState(icicle);
mVisibleFromClient = !mWindow.getWindowStyle().getBoolean(
com.android.internal.R.styleable.Window_windowNoDisplay, false);
mFragments.dispatchActivityCreated();
mActivityTransitionState.setEnterActivityOptions(this, getActivityOptions());
}
到此activity的启动完成。
