startActivity到底发生了什么？
大家好不好奇，我们平常使用的最多的startActivity这个方法底层到底是什么样子的？本篇文章就为大家来解密！
本文主要源码的位置如下：
frameworks/base/services/core/java/com/android/server/wm
我们先根据下面的图从宏观上看一下startActivity发生了什么.
一、App进程中
startActivity方法的调用链如下：
在Activity中:
startActivity -> startActivityForResult -> mInstrumentation.execStartActivity -> ActivityTaskManager.getService().startActivity.
ActivityTaskManager.getService()是从单例对象中，通过binder跨进程调用拿到的是一个IActivityTaskManager, 它是ActivityTaskManagerService的一个代理对象, 然后调动的是其startActivity方法，然后后面的逻辑都是在系统进程完成的。
源码如下：
private static final Singleton<IActivityTaskManager> IActivityTaskManagerSingleton =
new Singleton<IActivityTaskManager>() {
@Override
protected IActivityTaskManager create() {
final IBinder b = ServiceManager.getService(Context.ACTIVITY_TASK_SERVICE);
return IActivityTaskManager.Stub.asInterface(b);
}
};
二、系统进程中
startActivity快进程调用了ActivityTaskManagerService的startActivityAsUser方法。
我们查看一下源码：
ActivityTaskManagerService的
startActivityAsUser方法，展开查看
private int startActivityAsUser(
IApplicationThread caller, String callingPackage,
@Nullable String callingFeatureId, Intent intent, String resolvedType,
IBinder resultTo, String resultWho, int requestCode, int startFlags,
ProfilerInfo profilerInfo, Bundle bOptions, int userId, boolean validateIncomingUser) {
final SafeActivityOptions opts = SafeActivityOptions.fromBundle(bOptions);
assertPackageMatchesCallingUid(callingPackage);
enforceNotIsolatedCaller("startActivityAsUser");
if (isSdkSandboxActivityIntent(mContext, intent)) {
SdkSandboxManagerLocal sdkSandboxManagerLocal = LocalManagerRegistry.getManager(
SdkSandboxManagerLocal.class);
sdkSandboxManagerLocal.enforceAllowedToHostSandboxedActivity(
intent, Binder.getCallingUid(), callingPackage
);
}
if (Process.isSdkSandboxUid(Binder.getCallingUid())) {
SdkSandboxManagerLocal sdkSandboxManagerLocal = LocalManagerRegistry.getManager(
SdkSandboxManagerLocal.class);
if (sdkSandboxManagerLocal == null) {
throw new IllegalStateException("SdkSandboxManagerLocal not found when starting"
+ " an activity from an SDK sandbox uid.");
}
sdkSandboxManagerLocal.enforceAllowedToStartActivity(intent);
}
userId = getActivityStartController().checkTargetUser(userId, validateIncomingUser,
Binder.getCallingPid(), Binder.getCallingUid(), "startActivityAsUser");
// TODO: Switch to user app stacks here.
return getActivityStartController().obtainStarter(intent, "startActivityAsUser")
.setCaller(caller)
.setCallingPackage(callingPackage)
.setCallingFeatureId(callingFeatureId)
.setResolvedType(resolvedType)
.setResultTo(resultTo)
.setResultWho(resultWho)
.setRequestCode(requestCode)
.setStartFlags(startFlags)
.setProfilerInfo(profilerInfo)
.setActivityOptions(opts)
.setUserId(userId)
.execute();
}
由源码可知，又调用了ActivityStartController对象的obtainStarter方法.
obtainStarter源码如下
ActivityStarter obtainStarter(Intent intent, String reason) {
return mFactory
.obtain().setIntent(intent).setReason(reason);
}
由源码可知通过链式调用返回了一个ActivityStarter对象，所以obtainStarter返回的ActivityStarter也通过链式调用最后执行到execute方法，我们查看下其源码：
ActivityStarter.java
int execute() {
// Required for logging ContentOrFileUriEventReported in the finally block.
String callerActivityName = null;
ActivityRecord launchingRecord = null;
try {
onExecutionStarted();
if (mRequest.intent != null) {
// Refuse possible leaked file descriptors
if (mRequest.intent.hasFileDescriptors()) {
throw new IllegalArgumentException("File descriptors passed in Intent");
}
// Remove existing mismatch flag so it can be properly updated later
mRequest.intent.removeExtendedFlags(Intent.EXTENDED_FLAG_FILTER_MISMATCH);
}
final LaunchingState launchingState;
synchronized (mService.mGlobalLock) {
final ActivityRecord caller = ActivityRecord.forTokenLocked(mRequest.resultTo);
final int callingUid = mRequest.realCallingUid == Request.DEFAULT_REAL_CALLING_UID
? Binder.getCallingUid() : mRequest.realCallingUid;
launchingState = mSupervisor.getActivityMetricsLogger().notifyActivityLaunching(
mRequest.intent, caller, callingUid);
callerActivityName = caller != null ? caller.info.name : null;
}
if (mRequest.intent != null) {
mRequest.componentSpecified |= mRequest.intent.getComponent() != null;
}
// If the caller hasn't already resolved the activity, we're willing
// to do so here. If the caller is already holding the WM lock here,
// and we need to check dynamic Uri permissions, then we're forced
// to assume those permissions are denied to avoid deadlocking.
if (mRequest.activityInfo == null) {
mRequest.resolveActivity(mSupervisor);
}
// Add checkpoint for this shutdown or reboot attempt, so we can record the original
// intent action and package name.
if (mRequest.intent != null) {
String intentAction = mRequest.intent.getAction();
String callingPackage = mRequest.callingPackage;
if (intentAction != null && callingPackage != null
&& (Intent.ACTION_REQUEST_SHUTDOWN.equals(intentAction)
|| Intent.ACTION_SHUTDOWN.equals(intentAction)
|| Intent.ACTION_REBOOT.equals(intentAction))) {
ShutdownCheckPoints.recordCheckPoint(intentAction, callingPackage, null);
}
}
int res = START_CANCELED;
synchronized (mService.mGlobalLock) {
final boolean globalConfigWillChange = mRequest.globalConfig != null
&& mService.getGlobalConfiguration().diff(mRequest.globalConfig) != 0;
final Task rootTask = mRootWindowContainer.getTopDisplayFocusedRootTask();
if (rootTask != null) {
rootTask.mConfigWillChange = globalConfigWillChange;
}
ProtoLog.v(WM_DEBUG_CONFIGURATION, "Starting activity when config "
+ "will change = %b", globalConfigWillChange);
final long origId = Binder.clearCallingIdentity();
try {
res = resolveToHeavyWeightSwitcherIfNeeded();
if (res != START_SUCCESS) {
return res;
}
res = executeRequest(mRequest); // 1
} finally {
Binder.restoreCallingIdentity(origId);
mRequest.logMessage.append(" result code=").append(res);
Slog.i(TAG, mRequest.logMessage.toString());
mRequest.logMessage.setLength(0);
}
if (globalConfigWillChange) {
// If the caller also wants to switch to a new configuration, do so now.
// This allows a clean switch, as we are waiting for the current activity
// to pause (so we will not destroy it), and have not yet started the
// next activity.
mService.mAmInternal.enforceCallingPermission(
android.Manifest.permission.CHANGE_CONFIGURATION,
"updateConfiguration()");
if (rootTask != null) {
rootTask.mConfigWillChange = false;
}
ProtoLog.v(WM_DEBUG_CONFIGURATION,
"Updating to new configuration after starting activity.");
mService.updateConfigurationLocked(mRequest.globalConfig, null, false);
}
// The original options may have additional info about metrics. The mOptions is not
// used here because it may be cleared in setTargetRootTaskIfNeeded.
final ActivityOptions originalOptions = mRequest.activityOptions != null
? mRequest.activityOptions.getOriginalOptions() : null;
// Only track the launch time of activity that will be resumed.
launchingRecord = mDoResume ? mLastStartActivityRecord : null;
// If the new record is the one that started, a new activity has created.
final boolean newActivityCreated = mStartActivity == launchingRecord;
// Notify ActivityMetricsLogger that the activity has launched.
// ActivityMetricsLogger will then wait for the windows to be drawn and populate
// WaitResult.
mSupervisor.getActivityMetricsLogger().notifyActivityLaunched(launchingState, res,
newActivityCreated, launchingRecord, originalOptions);
if (mRequest.waitResult != null) {
mRequest.waitResult.result = res;
res = waitResultIfNeeded(mRequest.waitResult, mLastStartActivityRecord,
launchingState);
}
return getExternalResult(res);
}
} finally {
// Notify UriGrantsManagerService that activity launch completed. Required for logging
// the ContentOrFileUriEventReported message.
mSupervisor.mService.mUgmInternal.notifyActivityLaunchRequestCompleted(
mRequest.hashCode(),
// isSuccessfulLaunch
launchingRecord != null,
// Intent action
mRequest.intent != null ? mRequest.intent.getAction() : null,
mRequest.realCallingUid,
callerActivityName,
// Callee UID
mRequest.activityInfo != null
? mRequest.activityInfo.applicationInfo.uid : INVALID_UID,
// Callee Activity name
mRequest.activityInfo != null ? mRequest.activityInfo.name : null,
// isStartActivityForResult
launchingRecord != null && launchingRecord.resultTo != null);
onExecutionComplete();
}
}
位置1处是真正完成Activity启动流程的代码。
其源码如下：
ActivityStarter.java
/**
* Executing activity start request and starts the journey of starting an activity. Here
* begins with performing several preliminary checks. The normally activity launch flow will
* go through {@link #startActivityUnchecked} to {@link #startActivityInner}.
*/
private int executeRequest(Request request) {
if (TextUtils.isEmpty(request.reason)) {
throw new IllegalArgumentException("Need to specify a reason.");
}
mLastStartReason = request.reason;
mLastStartActivityTimeMs = System.currentTimeMillis();
final IApplicationThread caller = request.caller;
Intent intent = request.intent;
NeededUriGrants intentGrants = request.intentGrants;
String resolvedType = request.resolvedType;
ActivityInfo aInfo = request.activityInfo;
ResolveInfo rInfo = request.resolveInfo;
final IVoiceInteractionSession voiceSession = request.voiceSession;
final IBinder resultTo = request.resultTo;
String resultWho = request.resultWho;
int requestCode = request.requestCode;
int callingPid = request.callingPid;
int callingUid = request.callingUid;
String callingPackage = request.callingPackage;
String callingFeatureId = request.callingFeatureId;
final int realCallingPid = request.realCallingPid;
final int realCallingUid = request.realCallingUid;
final int startFlags = request.startFlags;
final SafeActivityOptions options = request.activityOptions;
Task inTask = request.inTask;
TaskFragment inTaskFragment = request.inTaskFragment;
int err = ActivityManager.START_SUCCESS;
// Pull the optional Ephemeral Installer-only bundle out of the options early.
final Bundle verificationBundle =
options != null ? options.popAppVerificationBundle() : null;
WindowProcessController callerApp = null;
if (caller != null) {
callerApp = mService.getProcessController(caller);
if (callerApp != null) {
callingPid = callerApp.getPid();
callingUid = callerApp.mInfo.uid;
} else {
Slog.w(TAG, "Unable to find app for caller " + caller + " (pid=" + callingPid
+ ") when starting: " + intent.toString());
err = START_PERMISSION_DENIED;
}
}
final int userId = aInfo != null && aInfo.applicationInfo != null
? UserHandle.getUserId(aInfo.applicationInfo.uid) : 0;
final int launchMode = aInfo != null ? aInfo.launchMode : 0;
if (err == ActivityManager.START_SUCCESS) {
request.logMessage.append("START u").append(userId).append(" {")
.append(intent.toShortString(true, true, true, false))
.append("} with ").append(launchModeToString(launchMode))
.append(" from uid ").append(callingUid);
if (callingUid != realCallingUid
&& realCallingUid != Request.DEFAULT_REAL_CALLING_UID) {
request.logMessage.append(" (realCallingUid=").append(realCallingUid).append(")");
}
}
ActivityRecord sourceRecord = null;
ActivityRecord resultRecord = null;
if (resultTo != null) {
sourceRecord = ActivityRecord.isInAnyTask(resultTo);
if (DEBUG_RESULTS) {
Slog.v(TAG_RESULTS, "Will send result to " + resultTo + " " + sourceRecord);
}
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.
if (requestCode >= 0) {
SafeActivityOptions.abort(options);
return ActivityManager.START_FORWARD_AND_REQUEST_CONFLICT;
}
resultRecord = sourceRecord.resultTo;
if (resultRecord != null && !resultRecord.isInRootTaskLocked()) {
resultRecord = null;
}
resultWho = sourceRecord.resultWho;
requestCode = sourceRecord.requestCode;
sourceRecord.resultTo = null;
if (resultRecord != null) {
resultRecord.removeResultsLocked(sourceRecord, resultWho, requestCode);
}
if (sourceRecord.launchedFromUid == callingUid) {
// The new activity is being launched from the same uid as the previous activity
// in the flow, and asking to forward its result back to the previous. In this
// case the activity is serving as a trampoline between the two, so we also want
// to update its launchedFromPackage to be the same as the previous activity.
// Note that this is safe, since we know these two packages come from the same
// uid; the caller could just as well have supplied that same package name itself
// . This specifially deals with the case of an intent picker/chooser being
// launched in the app flow to redirect to an activity picked by the user, where
// we want the final activity to consider it to have been launched by the
// previous app activity.
callingPackage = sourceRecord.launchedFromPackage;
callingFeatureId = sourceRecord.launchedFromFeatureId;
}
}
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!
err = ActivityManager.START_INTENT_NOT_RESOLVED;
}
if (err == ActivityManager.START_SUCCESS && aInfo == null) {
// We couldn't find the specific class specified in the Intent.
err = ActivityManager.START_CLASS_NOT_FOUND;
if (isArchivingEnabled()) {
PackageArchiver packageArchiver = mService
.getPackageManagerInternalLocked()
.getPackageArchiver();
if (packageArchiver.isIntentResolvedToArchivedApp(intent, mRequest.userId)) {
err = packageArchiver
.requestUnarchiveOnActivityStart(
intent, callingPackage, mRequest.userId, realCallingUid);
}
}
}
if (err == ActivityManager.START_SUCCESS && sourceRecord != null
&& sourceRecord.getTask().voiceSession != null) {
// If this activity is being launched as part of a voice session, we need to ensure
// that it is safe to do so. If the upcoming activity will also be part of the voice
// session, we can only launch it if it has explicitly said it supports the VOICE
// category, or it is a part of the calling app.
if ((launchFlags & FLAG_ACTIVITY_NEW_TASK) == 0
&& sourceRecord.info.applicationInfo.uid != aInfo.applicationInfo.uid) {
try {
intent.addCategory(Intent.CATEGORY_VOICE);
if (!mService.getPackageManager().activitySupportsIntentAsUser(
intent.getComponent(), intent, resolvedType, userId)) {
Slog.w(TAG, "Activity being started in current voice task does not support "
+ "voice: " + intent);
err = ActivityManager.START_NOT_VOICE_COMPATIBLE;
}
} catch (RemoteException e) {
Slog.w(TAG, "Failure checking voice capabilities", e);
err = ActivityManager.START_NOT_VOICE_COMPATIBLE;
}
}
}
if (err == ActivityManager.START_SUCCESS && voiceSession != null) {
// If the caller is starting a new voice session, just make sure the target
// is actually allowing it to run this way.
try {
if (!mService.getPackageManager().activitySupportsIntentAsUser(
intent.getComponent(), intent, resolvedType, userId)) {
Slog.w(TAG,
"Activity being started in new voice task does not support: " + intent);
err = ActivityManager.START_NOT_VOICE_COMPATIBLE;
}
} catch (RemoteException e) {
Slog.w(TAG, "Failure checking voice capabilities", e);
err = ActivityManager.START_NOT_VOICE_COMPATIBLE;
}
}
final Task resultRootTask = resultRecord == null
? null : resultRecord.getRootTask();
if (err != START_SUCCESS) {
if (resultRecord != null) {
resultRecord.sendResult(INVALID_UID, resultWho, requestCode, RESULT_CANCELED,
null /* data */, null /* callerToken */, null /* dataGrants */);
}
SafeActivityOptions.abort(options);
return err;
}
boolean abort;
try {
abort = !mSupervisor.checkStartAnyActivityPermission(intent, aInfo, resultWho,
requestCode, callingPid, callingUid, callingPackage, callingFeatureId,
request.ignoreTargetSecurity, inTask != null, callerApp, resultRecord,
resultRootTask);
} catch (SecurityException e) {
// Return activity not found for the explicit intent if the caller can't see the target
// to prevent the disclosure of package existence.
final Intent originalIntent = request.ephemeralIntent;
if (originalIntent != null && (originalIntent.getComponent() != null
|| originalIntent.getPackage() != null)) {
final String targetPackageName = originalIntent.getComponent() != null
? originalIntent.getComponent().getPackageName()
: originalIntent.getPackage();
if (mService.getPackageManagerInternalLocked()
.filterAppAccess(targetPackageName, callingUid, userId)) {
if (resultRecord != null) {
resultRecord.sendResult(INVALID_UID, resultWho, requestCode,
RESULT_CANCELED, null /* data */, null /* callerToken */,
null /* dataGrants */);
}
SafeActivityOptions.abort(options);
return ActivityManager.START_CLASS_NOT_FOUND;
}
}
throw e;
}
abort |= !mService.mIntentFirewall.checkStartActivity(intent, callingUid,
callingPid, resolvedType, aInfo.applicationInfo);
abort |= !mService.getPermissionPolicyInternal().checkStartActivity(intent, callingUid,
callingPackage);
// Merge the two options bundles, while realCallerOptions takes precedence.
ActivityOptions checkedOptions = options != null
? options.getOptions(intent, aInfo, callerApp, mSupervisor) : null;
final BalVerdict balVerdict;
if (!abort) {
try {
Trace.traceBegin(Trace.TRACE_TAG_WINDOW_MANAGER,
"shouldAbortBackgroundActivityStart");
BackgroundActivityStartController balController =
mSupervisor.getBackgroundActivityLaunchController();
balVerdict =
balController.checkBackgroundActivityStart(
callingUid,
callingPid,
callingPackage,
realCallingUid,
realCallingPid,
callerApp,
request.originatingPendingIntent,
request.forcedBalByPiSender,
resultRecord,
intent,
checkedOptions);
request.logMessage.append(" (").append(balVerdict).append(")");
} finally {
Trace.traceEnd(Trace.TRACE_TAG_WINDOW_MANAGER);
}
} else {
// Sets ALLOW_BY_DEFAULT as default value as the activity launch will be aborted anyway.
balVerdict = BalVerdict.ALLOW_BY_DEFAULT;
}
if (request.allowPendingRemoteAnimationRegistryLookup) {
checkedOptions = mService.getActivityStartController()
.getPendingRemoteAnimationRegistry()
.overrideOptionsIfNeeded(callingPackage, checkedOptions);
}
if (mService.mController != null) {
try {
// The Intent we give to the watcher has the extra data stripped off, since it
// can contain private information.
Intent watchIntent = intent.cloneFilter();
abort |= !mService.mController.activityStarting(watchIntent,
aInfo.applicationInfo.packageName);
} catch (RemoteException e) {
mService.mController = null;
}
}
final TaskDisplayArea suggestedLaunchDisplayArea =
computeSuggestedLaunchDisplayArea(inTask, sourceRecord, checkedOptions);
mInterceptor.setStates(userId, realCallingPid, realCallingUid, startFlags, callingPackage,
callingFeatureId);
if (mInterceptor.intercept(intent, rInfo, aInfo, resolvedType, inTask, inTaskFragment,
callingPid, callingUid, checkedOptions, suggestedLaunchDisplayArea)) {
// activity start was intercepted, e.g. because the target user is currently in quiet
// mode (turn off work) or the target application is suspended
intent = mInterceptor.mIntent;
rInfo = mInterceptor.mRInfo;
aInfo = mInterceptor.mAInfo;
resolvedType = mInterceptor.mResolvedType;
inTask = mInterceptor.mInTask;
callingPid = mInterceptor.mCallingPid;
callingUid = mInterceptor.mCallingUid;
checkedOptions = mInterceptor.mActivityOptions;
// The interception target shouldn't get any permission grants
// intended for the original destination
intentGrants = null;
}
if (abort) {
if (resultRecord != null) {
resultRecord.sendResult(INVALID_UID, resultWho, requestCode, RESULT_CANCELED,
null /* data */, null /* callerToken */, null /* dataGrants */);
}
// We pretend to the caller that it was really started, but they will just get a
// cancel result.
ActivityOptions.abort(checkedOptions);
return START_ABORTED;
}
// If permissions need a review before any of the app components can run, we
// launch the review activity and pass a pending intent to start the activity
// we are to launching now after the review is completed.
if (aInfo != null) {
if (mService.getPackageManagerInternalLocked().isPermissionsReviewRequired(
aInfo.packageName, userId)) {
final IIntentSender target = mService.getIntentSenderLocked(
ActivityManager.INTENT_SENDER_ACTIVITY, callingPackage, callingFeatureId,
callingUid, userId, null, null, 0, new Intent[]{intent},
new String[]{resolvedType}, PendingIntent.FLAG_CANCEL_CURRENT
| PendingIntent.FLAG_ONE_SHOT, null);
Intent newIntent = new Intent(Intent.ACTION_REVIEW_PERMISSIONS);
int flags = intent.getFlags();
flags |= Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS;
/*
* Prevent reuse of review activity: Each app needs their own review activity. By
* default activities launched with NEW_TASK or NEW_DOCUMENT try to reuse activities
* with the same launch parameters (extras are ignored). Hence to avoid possible
* reuse force a new activity via the MULTIPLE_TASK flag.
*
* Activities that are not launched with NEW_TASK or NEW_DOCUMENT are not re-used,
* hence no need to add the flag in this case.
*/
if ((flags & (FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_NEW_DOCUMENT)) != 0) {
flags |= Intent.FLAG_ACTIVITY_MULTIPLE_TASK;
}
newIntent.setFlags(flags);
newIntent.putExtra(Intent.EXTRA_PACKAGE_NAME, aInfo.packageName);
newIntent.putExtra(Intent.EXTRA_INTENT, new IntentSender(target));
if (resultRecord != null) {
newIntent.putExtra(Intent.EXTRA_RESULT_NEEDED, true);
}
intent = newIntent;
// The permissions review target shouldn't get any permission
// grants intended for the original destination
intentGrants = null;
resolvedType = null;
callingUid = realCallingUid;
callingPid = realCallingPid;
rInfo = mSupervisor.resolveIntent(intent, resolvedType, userId, 0,
computeResolveFilterUid(
callingUid, realCallingUid, request.filterCallingUid),
realCallingPid);
aInfo = mSupervisor.resolveActivity(intent, rInfo, startFlags,
null /*profilerInfo*/);
if (DEBUG_PERMISSIONS_REVIEW) {
final Task focusedRootTask =
mRootWindowContainer.getTopDisplayFocusedRootTask();
Slog.i(TAG, "START u" + userId + " {" + intent.toShortString(true, true,
true, false) + "} from uid " + callingUid + " on display "
+ (focusedRootTask == null ? DEFAULT_DISPLAY
: focusedRootTask.getDisplayId()));
}
}
}
// If we have an ephemeral app, abort the process of launching the resolved intent.
// Instead, launch the ephemeral installer. Once the installer is finished, it
// starts either the intent we resolved here [on install error] or the ephemeral
// app [on install success].
if (rInfo != null && rInfo.auxiliaryInfo != null) {
intent = createLaunchIntent(rInfo.auxiliaryInfo, request.ephemeralIntent,
callingPackage, callingFeatureId, verificationBundle, resolvedType, userId);
resolvedType = null;
callingUid = realCallingUid;
callingPid = realCallingPid;
// The ephemeral installer shouldn't get any permission grants
// intended for the original destination
intentGrants = null;
aInfo = mSupervisor.resolveActivity(intent, rInfo, startFlags, null /*profilerInfo*/);
}
// TODO (b/187680964) Correcting the caller/pid/uid when start activity from shortcut
// Pending intent launched from systemui also depends on caller app
if (callerApp == null && realCallingPid > 0) {
final WindowProcessController wpc = mService.mProcessMap.getProcess(realCallingPid);
if (wpc != null) {
callerApp = wpc;
}
}
final ActivityRecord r = new ActivityRecord.Builder(mService)
.setCaller(callerApp)
.setLaunchedFromPid(callingPid)
.setLaunchedFromUid(callingUid)
.setLaunchedFromPackage(callingPackage)
.setLaunchedFromFeature(callingFeatureId)
.setIntent(intent)
.setResolvedType(resolvedType)
.setActivityInfo(aInfo)
.setConfiguration(mService.getGlobalConfiguration())
.setResultTo(resultRecord)
.setResultWho(resultWho)
.setRequestCode(requestCode)
.setComponentSpecified(request.componentSpecified)
.setRootVoiceInteraction(voiceSession != null)
.setActivityOptions(checkedOptions)
.setSourceRecord(sourceRecord)
.build();
mLastStartActivityRecord = 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;
}
// Only allow app switching to be resumed if activity is not a restricted background
// activity and target app is not home process, otherwise any background activity
// started in background task can stop home button protection mode.
// As the targeted app is not a home process and we don't need to wait for the 2nd
// activity to be started to resume app switching, we can just enable app switching
// directly.
WindowProcessController homeProcess = mService.mHomeProcess;
boolean isHomeProcess = homeProcess != null
&& aInfo.applicationInfo.uid == homeProcess.mUid;
if (balVerdict.allows() && !isHomeProcess) {
mService.resumeAppSwitches();
}
// Only do the create here since startActivityInner can abort. If it doesn't abort,
// the requestStart will be sent in handleStartRequest.
final Transition newTransition = r.mTransitionController.isShellTransitionsEnabled()
? r.mTransitionController.createAndStartCollecting(TRANSIT_OPEN) : null;
// Because startActivity must run immediately, it can get combined with another
// transition meaning it is no-longer independent. This is NOT desirable, but is the
// only option for the time being.
final boolean isIndependent = newTransition != null;
final Transition transition = isIndependent ? newTransition
: mService.getTransitionController().getCollectingTransition();
// 1
mLastStartActivityResult = startActivityUnchecked(r, sourceRecord, voiceSession,
request.voiceInteractor, startFlags, checkedOptions,
inTask, inTaskFragment, balVerdict, intentGrants, realCallingUid, transition,
isIndependent);
if (request.outActivity != null) {
request.outActivity[0] = mLastStartActivityRecord;
}
return mLastStartActivityResult;
}
有文档注释可知：
startActivityUnchecked -> startActivityInner
startActivityUnchecked源码如下：
ActivityStarter.java
/**
* Start an activity while most of preliminary checks has been done and caller has been
* confirmed that holds necessary permissions to do so.
* Here also ensures that the starting activity is removed if the start wasn't successful.
*/
private int startActivityUnchecked(
final ActivityRecord r, ActivityRecord sourceRecord,
IVoiceInteractionSession voiceSession, IVoiceInteractor voiceInteractor,
int startFlags, ActivityOptions options, Task inTask,
TaskFragment inTaskFragment,
BalVerdict balVerdict,
NeededUriGrants intentGrants, int realCallingUid, Transition transition,
boolean isIndependentLaunch) {
int result = START_CANCELED;
final Task startedActivityRootTask;
RemoteTransition remoteTransition = r.takeRemoteTransition();
// Create a display snapshot as soon as possible.
if (isIndependentLaunch && mRequest.freezeScreen) {
final TaskDisplayArea tda = mLaunchParams.hasPreferredTaskDisplayArea()
? mLaunchParams.mPreferredTaskDisplayArea
: mRootWindowContainer.getDefaultTaskDisplayArea();
final DisplayContent dc = mRootWindowContainer.getDisplayContentOrCreate(
tda.getDisplayId());
if (dc != null) {
transition.collect(dc);
transition.collectVisibleChange(dc);
}
}
try {
mService.deferWindowLayout();
r.mTransitionController.collect(r);
try {
Trace.traceBegin(Trace.TRACE_TAG_WINDOW_MANAGER, "startActivityInner");
result = startActivityInner(r, sourceRecord, voiceSession, voiceInteractor, // 1
startFlags, options, inTask, inTaskFragment, balVerdict,
intentGrants, realCallingUid);
} catch (Exception ex) {
Slog.e(TAG, "Exception on startActivityInner", ex);
} finally {
Trace.traceEnd(Trace.TRACE_TAG_WINDOW_MANAGER);
startedActivityRootTask = handleStartResult(r, options, result, isIndependentLaunch,
remoteTransition, transition);
}
} finally {
mService.continueWindowLayout();
}
postStartActivityProcessing(r, result, startedActivityRootTask);
return result;
}
startActivityInner源码如下：
ActivityStarter.java
/**
* Start an activity and determine if the activity should be adding to the top of an existing
* task or delivered new intent to an existing activity. Also manipulating the activity task
* onto requested or valid root-task/display.
*
* Note: This method should only be called from {@link #startActivityUnchecked}.
*/
// TODO(b/152429287): Make it easier to exercise code paths through startActivityInner
@VisibleForTesting
int startActivityInner(
final ActivityRecord r, ActivityRecord sourceRecord,
IVoiceInteractionSession voiceSession, IVoiceInteractor voiceInteractor,
int startFlags, ActivityOptions options, Task inTask,
TaskFragment inTaskFragment, BalVerdict balVerdict,
NeededUriGrants intentGrants, int realCallingUid) {
setInitialState(r, options, inTask, inTaskFragment, startFlags, sourceRecord,
voiceSession, voiceInteractor, balVerdict.getCode(), realCallingUid);
computeLaunchingTaskFlags();
mIntent.setFlags(mLaunchFlags);
boolean dreamStopping = false;
for (ActivityRecord stoppingActivity : mSupervisor.mStoppingActivities) {
if (stoppingActivity.getActivityType()
== WindowConfiguration.ACTIVITY_TYPE_DREAM) {
dreamStopping = true;
break;
}
}
// Get top task at beginning because the order may be changed when reusing existing task.
final Task prevTopRootTask = mPreferredTaskDisplayArea.getFocusedRootTask();
final Task prevTopTask = prevTopRootTask != null ? prevTopRootTask.getTopLeafTask() : null;
final boolean sourceActivityLaunchedFromBubble =
sourceRecord != null && sourceRecord.getLaunchedFromBubble();
// if the flag is enabled, allow reusing bubbled tasks only if the source activity is
// bubbled.
final boolean includeLaunchedFromBubble =
Flags.onlyReuseBubbledTaskWhenLaunchedFromBubble()
? sourceActivityLaunchedFromBubble : true;
final Task reusedTask = resolveReusableTask(includeLaunchedFromBubble);
// If requested, freeze the task list
if (mOptions != null && mOptions.freezeRecentTasksReordering()
&& mSupervisor.mRecentTasks.isCallerRecents(r.launchedFromUid)
&& !mSupervisor.mRecentTasks.isFreezeTaskListReorderingSet()) {
mFrozeTaskList = true;
mSupervisor.mRecentTasks.setFreezeTaskListReordering();
}
// Compute if there is an existing task that should be used for.
final Task targetTask = reusedTask != null ? reusedTask : computeTargetTask();
final boolean newTask = targetTask == null;
mTargetTask = targetTask;
computeLaunchParams(r, sourceRecord, targetTask);
// Check if starting activity on given task or on a new task is allowed.
int startResult = isAllowedToStart(r, newTask, targetTask);
if (startResult != START_SUCCESS) {
if (r.resultTo != null) {
r.resultTo.sendResult(INVALID_UID, r.resultWho, r.requestCode, RESULT_CANCELED,
null /* data */, null /* callerToken */, null /* dataGrants */);
}
return startResult;
}
if (targetTask != null) {
if (targetTask.getTreeWeight() > MAX_TASK_WEIGHT_FOR_ADDING_ACTIVITY) {
Slog.e(TAG, "Remove " + targetTask + " because it has contained too many"
+ " activities or windows (abort starting " + r
+ " from uid=" + mCallingUid);
targetTask.removeImmediately("bulky-task");
return START_ABORTED;
}
// When running transient transition, the transient launch target should keep on top.
// So disallow the transient hide activity to move itself to front, e.g. trampoline.
if (!avoidMoveToFront() && (mService.mHomeProcess == null
|| mService.mHomeProcess.mUid != realCallingUid)
&& (prevTopTask != null && prevTopTask.isActivityTypeHomeOrRecents())
&& r.mTransitionController.isTransientHide(targetTask)) {
mCanMoveToFrontCode = MOVE_TO_FRONT_AVOID_LEGACY;
}
// If the activity is started by sending a pending intent and only its creator has the
// privilege to allow BAL (its sender does not), avoid move it to the front. Only do
// this when it is not a new task and not already been marked as avoid move to front.
// Guarded by a flag: balDontBringExistingBackgroundTaskStackToFg
if (balDontBringExistingBackgroundTaskStackToFg() && !avoidMoveToFront()
&& balVerdict.onlyCreatorAllows()) {
mCanMoveToFrontCode = MOVE_TO_FRONT_AVOID_PI_ONLY_CREATOR_ALLOWS;
}
mPriorAboveTask = TaskDisplayArea.getRootTaskAbove(targetTask.getRootTask());
}
final ActivityRecord targetTaskTop = newTask
? null : targetTask.getTopNonFinishingActivity();
if (targetTaskTop != null) {
// Removes the existing singleInstance activity in another task (if any) while
// launching a singleInstance activity on sourceRecord's task.
if (LAUNCH_SINGLE_INSTANCE == mLaunchMode && mSourceRecord != null
&& targetTask == mSourceRecord.getTask()) {
final ActivityRecord activity = mRootWindowContainer.findActivity(mIntent, mStartActivity.info, false);
if (activity != null && activity.getTask() != targetTask) {
activity.destroyIfPossible("Removes redundant singleInstance");
}
}
if (mLastStartActivityRecord != null) {
targetTaskTop.mLaunchSourceType = mLastStartActivityRecord.mLaunchSourceType;
}
targetTaskTop.mTransitionController.collect(targetTaskTop);
recordTransientLaunchIfNeeded(targetTaskTop);
// Recycle the target task for this launch.
startResult =
recycleTask(targetTask, targetTaskTop, reusedTask, intentGrants, balVerdict);
if (startResult != START_SUCCESS) {
return startResult;
}
} else {
mAddingToTask = true;
}
// If the activity being launched is the same as the one currently at the top, then
// we need to check if it should only be launched once.
final Task topRootTask = mPreferredTaskDisplayArea.getFocusedRootTask();
if (topRootTask != null) {
startResult = deliverToCurrentTopIfNeeded(topRootTask, intentGrants);
if (startResult != START_SUCCESS) {
return startResult;
}
}
if (mTargetRootTask == null) {
mTargetRootTask = getOrCreateRootTask(mStartActivity, mLaunchFlags, targetTask,
mOptions);
}
if (newTask) {
final Task taskToAffiliate = (mLaunchTaskBehind && mSourceRecord != null)
? mSourceRecord.getTask() : null;
setNewTask(taskToAffiliate);
} else if (mAddingToTask) {
addOrReparentStartingActivity(targetTask, "adding to task");
}
// After activity is attached to task, but before actual start
recordTransientLaunchIfNeeded(mLastStartActivityRecord);
if (mDoResume) {
if (!avoidMoveToFront()) {
mTargetRootTask.getRootTask().moveToFront("reuseOrNewTask", targetTask);
if (!mTargetRootTask.isTopRootTaskInDisplayArea() && mService.isDreaming()
&& !dreamStopping) {
// Launching underneath dream activity (fullscreen, always-on-top). Run the
// launch--behind transition so the Activity gets created and starts
// in visible state.
mLaunchTaskBehind = true;
r.mLaunchTaskBehind = true;
}
} else {
logPIOnlyCreatorAllowsBAL();
}
}
mService.mUgmInternal.grantUriPermissionUncheckedFromIntent(intentGrants, mStartActivity.getUriPermissionsLocked());
if (mStartActivity.resultTo != null && mStartActivity.resultTo.info != null) {
// we need to resolve resultTo to a uid as grantImplicitAccess deals explicitly in UIDs
final PackageManagerInternal pmInternal =
mService.getPackageManagerInternalLocked();
final int resultToUid = pmInternal.getPackageUid(
mStartActivity.resultTo.info.packageName, 0 /* flags */,
mStartActivity.mUserId);
pmInternal.grantImplicitAccess(mStartActivity.mUserId, mIntent,
UserHandle.getAppId(mStartActivity.info.applicationInfo.uid) /*recipient*/,
resultToUid /*visible*/, true /*direct*/);
} else if (mStartActivity.mShareIdentity) {
final PackageManagerInternal pmInternal =
mService.getPackageManagerInternalLocked();
pmInternal.grantImplicitAccess(mStartActivity.mUserId, mIntent,
UserHandle.getAppId(mStartActivity.info.applicationInfo.uid) /*recipient*/,
r.launchedFromUid /*visible*/, true /*direct*/);
}
final Task startedTask = mStartActivity.getTask();
if (newTask) {
EventLogTags.writeWmCreateTask(mStartActivity.mUserId, startedTask.mTaskId,
startedTask.getRootTaskId(), startedTask.getDisplayId());
}
mStartActivity.logStartActivity(EventLogTags.WM_CREATE_ACTIVITY, startedTask);
mStartActivity.getTaskFragment().clearLastPausedActivity();
mRootWindowContainer.startPowerModeLaunchIfNeeded(
false /* forceSend */, mStartActivity);
final boolean isTaskSwitch = startedTask != prevTopTask;
mTargetRootTask.startActivityLocked(mStartActivity, topRootTask, newTask, isTaskSwitch,
mOptions, sourceRecord);
if (mDoResume) {
final ActivityRecord topTaskActivity = startedTask.topRunningActivityLocked();
if (!mTargetRootTask.isTopActivityFocusable()
|| (topTaskActivity != null && topTaskActivity.isTaskOverlay()
&& mStartActivity != topTaskActivity)) {
// If the activity is not focusable, we can't resume it, but still would like to
// make sure it becomes visible as it starts (this will also trigger entry
// animation). An example of this are PIP activities.
// Also, we don't want to resume activities in a task that currently has an overlay
// as the starting activity just needs to be in the visible paused state until the
// over is removed.
// Passing {@code null} as the start parameter ensures all activities are made
// visible.
mTargetRootTask.ensureActivitiesVisible(null /* starting */);
// Go ahead and tell window manager to execute app transition for this activity
// since the app transition will not be triggered through the resume channel.
mTargetRootTask.mDisplayContent.executeAppTransition();
} else {
// If the target root-task was not previously focusable (previous top running
// activity on that root-task was not visible) then any prior calls to move the
// root-task to the will not update the focused root-task. If starting the new
// activity now allows the task root-task to be focusable, then ensure that we
// now update the focused root-task accordingly.
if (mTargetRootTask.isTopActivityFocusable()
&& !mRootWindowContainer.isTopDisplayFocusedRootTask(mTargetRootTask)) {
if (!avoidMoveToFront()) {
mTargetRootTask.moveToFront("startActivityInner");
} else {
logPIOnlyCreatorAllowsBAL();
}
}
mRootWindowContainer.resumeFocusedTasksTopActivities(mTargetRootTask, mStartActivity, mOptions, mTransientLaunch); // 1
}
}
mRootWindowContainer.updateUserRootTask(mStartActivity.mUserId, mTargetRootTask);
// Update the recent tasks list immediately when the activity starts
mSupervisor.mRecentTasks.add(startedTask);
mSupervisor.handleNonResizableTaskIfNeeded(startedTask, mPreferredWindowingMode, mPreferredTaskDisplayArea, mTargetRootTask);
// If Activity's launching into PiP, move the mStartActivity immediately to pinned mode.
// Note that mStartActivity and source should be in the same Task at this point.
if (mOptions != null && mOptions.isLaunchIntoPip()
&& sourceRecord != null && sourceRecord.getTask() == mStartActivity.getTask()
&& balVerdict.allows()) {
mRootWindowContainer.moveActivityToPinnedRootTask(mStartActivity, sourceRecord, "launch-into-pip", null /* bounds */);
}
mSupervisor.getBackgroundActivityLaunchController()
.onNewActivityLaunched(mStartActivity); // mStartActivity 是 ActivityStarter对象的ActivityRecord类型的成员变量
return START_SUCCESS;
}
源码中
mStartActivity 是 ActivityStarter对象的ActivityRecord类型的成员变量.
mSupervisor是ActivityTaskSupervisor类型的对象，管理任务栈逻辑.
mRootWindowContainer是RootWindowContainer类型的对象.
我们看下RootWindowContainer类型的对象的resumeFocusedTasksTopActivities方法的源码：
frameworks/base/services/core/java/com/android/server/wm/RootWindowContainer.java
boolean resumeFocusedTasksTopActivities(
Task targetRootTask, ActivityRecord target, ActivityOptions targetOptions,
boolean deferPause) {
if (!mTaskSupervisor.readyToResume()) {
return false;
}
boolean result = false;
if (targetRootTask != null && (targetRootTask.isTopRootTaskInDisplayArea() || getTopDisplayFocusedRootTask() == targetRootTask)) {
result = targetRootTask.resumeTopActivityUncheckedLocked(target, targetOptions, deferPause);
}
for (int displayNdx = getChildCount() - 1; displayNdx >= 0; --displayNdx) {
final DisplayContent display = getChildAt(displayNdx);
final boolean curResult = result;
boolean[] resumedOnDisplay = new boolean[1];
final ActivityRecord topOfDisplay = display.topRunningActivity();
display.forAllRootTasks(rootTask -> {
final ActivityRecord topRunningActivity = rootTask.topRunningActivity();
if (!rootTask.isFocusableAndVisible() || topRunningActivity == null) {
return;
}
if (rootTask == targetRootTask) {
// Simply update the result for targetRootTask because the targetRootTask
// had already resumed in above. We don't want to resume it again,
// especially in some cases, it would cause a second launch failure
// if app process was dead.
resumedOnDisplay[0] |= curResult;
return;
}
if (topRunningActivity.isState(RESUMED) && topRunningActivity == topOfDisplay) {
// Kick off any lingering app transitions form the MoveTaskToFront operation,
// but only consider the top activity on that display.
rootTask.executeAppTransition(targetOptions);
} else {
resumedOnDisplay[0] |= topRunningActivity.makeActiveIfNeeded(target);
}
});
result |= resumedOnDisplay[0];
if (!resumedOnDisplay[0]) {
// In cases when there are no valid activities (e.g. device just booted or launcher
// crashed) it's possible that nothing was resumed on a display. Requesting resume
// of top activity in focused root task explicitly will make sure that at least home
// activity is started and resumed, and no recursion occurs.
final Task focusedRoot = display.getFocusedRootTask();
if (focusedRoot != null) {
result |= focusedRoot.resumeTopActivityUncheckedLocked(target, targetOptions, false /* skipPause */); // 1
} else if (targetRootTask == null) {
result |= resumeHomeActivity(null /* prev */, "no-focusable-task", display.getDefaultTaskDisplayArea());
}
}
}
return result;
}
focusedRoot是Task类型的对象，接下来查看方法resumeTopActivityUncheckedLocked的源码：
frameworks/base/services/core/java/com/android/server/wm/Task.java
/**
* Ensure that the top activity in the root task is resumed.
*
* @param prev The previously resumed activity, for when in the process
* of pausing; can be null to call from elsewhere.
* @param options Activity options.
* @param deferPause When {@code true}, this will not pause back tasks.
*
* @return Returns true if something is being resumed, or false if
* nothing happened.
*
* NOTE: It is not safe to call this method directly as it can cause an activity in a
* non-focused root task to be resumed.
* Use {@link RootWindowContainer#resumeFocusedTasksTopActivities} to resume the
* right activity for the current system state.
*/
@GuardedBy("mService")
boolean resumeTopActivityUncheckedLocked(ActivityRecord prev, ActivityOptions options, boolean deferPause) {
if (mInResumeTopActivity) {
// Don't even start recursing.
return false;
}
boolean someActivityResumed = false;
try {
// Protect against recursion.
mInResumeTopActivity = true;
if (isLeafTask()) {
if (isFocusableAndVisible()) {
someActivityResumed = resumeTopActivityInnerLocked(prev, options, deferPause); // 1
}
} else {
int idx = mChildren.size() - 1;
while (idx >= 0) {
final Task child = (Task) getChildAt(idx--);
if (!child.isTopActivityFocusable()) {
continue;
}
if (child.getVisibility(null /* starting */)
!= TASK_FRAGMENT_VISIBILITY_VISIBLE) {
if (child.topRunningActivity() == null) {
// Skip the task if no running activity and continue resuming next task.
continue;
}
// Otherwise, assuming everything behind this task should also be invisible.
break;
}
someActivityResumed |= child.resumeTopActivityUncheckedLocked(prev, options, deferPause);
// Doing so in order to prevent IndexOOB since hierarchy might changes while
// resuming activities, for example dismissing split-screen while starting
// non-resizeable activity.
if (idx >= mChildren.size()) {
idx = mChildren.size() - 1;
}
}
}
// When resuming the top activity, it may be necessary to pause the top activity (for
// example, returning to the lock screen. We suppress the normal pause logic in
// {@link #resumeTopActivityUncheckedLocked}, since the top activity is resumed at the
// end. We call the {@link ActivityTaskSupervisor#checkReadyForSleepLocked} again here
// to ensure any necessary pause logic occurs. In the case where the Activity will be
// shown regardless of the lock screen, the call to
// {@link ActivityTaskSupervisor#checkReadyForSleepLocked} is skipped.
final ActivityRecord next = topRunningActivity(true /* focusableOnly */);
if (next == null || !next.canTurnScreenOn()) {
checkReadyForSleep();
}
} finally {
mInResumeTopActivity = false;
}
return someActivityResumed;
}
继续看Task对象的resumeTopActivityInnerLocked方法：
@GuardedBy("mService")
private boolean resumeTopActivityInnerLocked(ActivityRecord prev, ActivityOptions options,
boolean deferPause) {
if (!mAtmService.isBooting() && !mAtmService.isBooted()) {
// Not ready yet!
return false;
}
final ActivityRecord topActivity = topRunningActivity(true /* focusableOnly */);
if (topActivity == null) {
// There are no activities left in this task, let's look somewhere else.
return resumeNextFocusableActivityWhenRootTaskIsEmpty(prev, options);
}
final boolean[] resumed = new boolean[1];
final TaskFragment topFragment = topActivity.getTaskFragment();
resumed[0] = topFragment.resumeTopActivity(prev, options, deferPause); // 1
forAllLeafTaskFragments(f -> {
if (topFragment == f) {
return;
}
if (!f.canBeResumed(null /* starting */)) {
return;
}
resumed[0] |= f.resumeTopActivity(prev, options, deferPause);
}, true);
return resumed[0];
}
TaskFragment的resumeTopActivity源码如下：
frameworks/base/services/core/java/com/android/server/wm/TaskFragment.java
final boolean resumeTopActivity(ActivityRecord prev, ActivityOptions options, boolean skipPause) {
ActivityRecord next = topRunningActivity(true /* focusableOnly */);
if (next == null || !next.canResumeByCompat()) {
return false;
}
next.delayedResume = false;
if (!skipPause && !mRootWindowContainer.allPausedActivitiesComplete()) {
// If we aren't skipping pause, then we have to wait for currently pausing activities.
ProtoLog.v(WM_DEBUG_STATES, "resumeTopActivity: Skip resume: some activity pausing.");
return false;
}
final TaskDisplayArea taskDisplayArea = getDisplayArea();
// If the top activity is the resumed one, nothing to do.
if (mResumedActivity == next && next.isState(RESUMED)
&& taskDisplayArea.allResumedActivitiesComplete()) {
// Ensure the visibility gets updated before execute app transition.
taskDisplayArea.ensureActivitiesVisible(null /* starting */, true /* notifyClients */);
// Make sure we have executed any pending transitions, since there
// should be nothing left to do at this point.
executeAppTransition(options);
// In a multi-resumed environment, like in a freeform device, the top
// activity can be resumed, but it might not be the focused app.
// Set focused app when top activity is resumed. However, we shouldn't do it for a
// same task because it can break focused state. (e.g. activity embedding)
if (taskDisplayArea.inMultiWindowMode() && taskDisplayArea.mDisplayContent != null) {
final ActivityRecord focusedApp = taskDisplayArea.mDisplayContent.mFocusedApp;
if (focusedApp == null || focusedApp.getTask() != next.getTask()) {
taskDisplayArea.mDisplayContent.setFocusedApp(next);
}
}
ProtoLog.d(WM_DEBUG_STATES, "resumeTopActivity: Top activity "
+ "resumed %s", next);
return false;
}
// If we are sleeping, and there is no resumed activity, and the top activity is paused,
// well that is the state we want.
if (mLastPausedActivity == next && shouldSleepOrShutDownActivities()) {
// Make sure we have executed any pending transitions, since there
// should be nothing left to do at this point.
executeAppTransition(options);
ProtoLog.d(WM_DEBUG_STATES, "resumeTopActivity: Going to sleep and"
+ " all paused");
return false;
}
// Make sure that the user who owns this activity is started. If not,
// we will just leave it as is because someone should be bringing
// another user's activities to the top of the stack.
if (!mAtmService.mAmInternal.hasStartedUserState(next.mUserId)) {
Slog.w(TAG, "Skipping resume of top activity " + next
+ ": user " + next.mUserId + " is stopped");
return false;
}
// The activity may be waiting for stop, but that is no longer
// appropriate for it.
mTaskSupervisor.mStoppingActivities.remove(next);
if (DEBUG_SWITCH) Slog.v(TAG_SWITCH, "Resuming " + next);
mTaskSupervisor.setLaunchSource(next.info.applicationInfo.uid);
ActivityRecord lastResumed = null;
final Task lastFocusedRootTask = taskDisplayArea.getLastFocusedRootTask();
if (lastFocusedRootTask != null && lastFocusedRootTask != getRootTaskFragment().asTask()) {
// So, why aren't we using prev here??? See the param comment on the method. prev
// doesn't represent the last resumed activity. However, the last focus stack does if
// it isn't null.
lastResumed = lastFocusedRootTask.getTopResumedActivity();
}
boolean pausing = !skipPause && taskDisplayArea.pauseBackTasks(next);
if (mResumedActivity != null) {
ProtoLog.d(WM_DEBUG_STATES, "resumeTopActivity: Pausing %s", mResumedActivity);
pausing |= startPausing(mTaskSupervisor.mUserLeaving, false /* uiSleeping */,
next, "resumeTopActivity");
}
if (pausing) {
ProtoLog.v(WM_DEBUG_STATES, "resumeTopActivity: Skip resume: need to"
+ " start pausing");
// At this point we want to put the upcoming activity's process
// at the top of the LRU list, since we know we will be needing it
// very soon and it would be a waste to let it get killed if it
// happens to be sitting towards the end.
if (next.attachedToProcess()) {
next.app.updateProcessInfo(false /* updateServiceConnectionActivities */,
true /* activityChange */, false /* updateOomAdj */,
false /* addPendingTopUid */);
} else if (!next.isProcessRunning()) {
// Since the start-process is asynchronous, if we already know the process of next
// activity isn't running, we can start the process earlier to save the time to wait
// for the current activity to be paused.
final boolean isTop = this == taskDisplayArea.getFocusedRootTask();
mAtmService.startProcessAsync(next, false /* knownToBeDead */, isTop,
isTop ? HostingRecord.HOSTING_TYPE_NEXT_TOP_ACTIVITY
: HostingRecord.HOSTING_TYPE_NEXT_ACTIVITY);
}
if (lastResumed != null) {
lastResumed.setWillCloseOrEnterPip(true);
}
return true;
} else if (mResumedActivity == next && next.isState(RESUMED)
&& taskDisplayArea.allResumedActivitiesComplete()) {
// It is possible for the activity to be resumed when we paused back stacks above if the
// next activity doesn't have to wait for pause to complete.
// So, nothing else to-do except:
// Make sure we have executed any pending transitions, since there
// should be nothing left to do at this point.
executeAppTransition(options);
ProtoLog.d(WM_DEBUG_STATES, "resumeTopActivity: Top activity resumed "
+ "(dontWaitForPause) %s", next);
return true;
}
// If the most recent activity was noHistory but was only stopped rather
// than stopped+finished because the device went to sleep, we need to make
// sure to finish it as we're making a new activity topmost.
if (shouldSleepActivities()) {
mTaskSupervisor.finishNoHistoryActivitiesIfNeeded(next);
}
if (prev != null && prev != next && next.nowVisible) {
// 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.
if (prev.finishing) {
prev.setVisibility(false);
if (DEBUG_SWITCH) {
Slog.v(TAG_SWITCH, "Not waiting for visible to hide: " + prev
+ ", nowVisible=" + next.nowVisible);
}
} else {
if (DEBUG_SWITCH) {
Slog.v(TAG_SWITCH, "Previous already visible but still waiting to hide: " + prev
+ ", nowVisible=" + next.nowVisible);
}
}
}
try {
mTaskSupervisor.getActivityMetricsLogger()
.notifyBeforePackageUnstopped(next.packageName);
mAtmService.getPackageManagerInternalLocked().notifyComponentUsed(
next.packageName, next.mUserId,
next.packageName, next.toString()); /* TODO: Verify if correct userid */
} catch (IllegalArgumentException e) {
Slog.w(TAG, "Failed trying to unstop package "
+ next.packageName + ": " + e);
}
// We are starting up the next activity, so tell the window manager
// that the previous one will be hidden soon. This way it can know
// to ignore it when computing the desired screen orientation.
boolean anim = true;
final DisplayContent dc = taskDisplayArea.mDisplayContent;
if (prev != null) {
if (prev.finishing) {
if (DEBUG_TRANSITION) {
Slog.v(TAG_TRANSITION, "Prepare close transition: prev=" + prev);
}
if (mTaskSupervisor.mNoAnimActivities.contains(prev)) {
anim = false;
dc.prepareAppTransition(TRANSIT_NONE);
} else {
dc.prepareAppTransition(TRANSIT_CLOSE);
}
prev.setVisibility(false);
} else {
if (DEBUG_TRANSITION) {
Slog.v(TAG_TRANSITION, "Prepare open transition: prev=" + prev);
}
if (mTaskSupervisor.mNoAnimActivities.contains(next)) {
anim = false;
dc.prepareAppTransition(TRANSIT_NONE);
} else {
dc.prepareAppTransition(TRANSIT_OPEN, next.mLaunchTaskBehind ? TRANSIT_FLAG_OPEN_BEHIND : 0);
}
}
} else {
if (DEBUG_TRANSITION) Slog.v(TAG_TRANSITION, "Prepare open transition: no previous");
if (mTaskSupervisor.mNoAnimActivities.contains(next)) {
anim = false;
dc.prepareAppTransition(TRANSIT_NONE);
} else {
dc.prepareAppTransition(TRANSIT_OPEN);
}
}
if (anim) {
next.applyOptionsAnimation();
} else {
next.abortAndClearOptionsAnimation();
}
mTaskSupervisor.mNoAnimActivities.clear();
if (next.attachedToProcess()) {
if (DEBUG_SWITCH) {
Slog.v(TAG_SWITCH, "Resume running: " + next + " stopped=" + next.mAppStopped
+ " visibleRequested=" + next.isVisibleRequested());
}
// If the previous activity is translucent, force a visibility update of
// the next activity, so that it's added to WM's opening app list, and
// transition animation can be set up properly.
// For example, pressing Home button with a translucent activity in focus.
// Launcher is already visible in this case. If we don't add it to opening
// apps, maybeUpdateTransitToWallpaper() will fail to identify this as a
// TRANSIT_WALLPAPER_OPEN animation, and run some funny animation.
final boolean lastActivityTranslucent = inMultiWindowMode()
|| mLastPausedActivity != null && !mLastPausedActivity.occludesParent();
// This activity is now becoming visible.
if (!next.isVisibleRequested() || next.mAppStopped || lastActivityTranslucent) {
next.app.addToPendingTop();
next.setVisibility(true);
}
// schedule launch ticks to collect information about slow apps.
next.startLaunchTickingLocked();
ActivityRecord lastResumedActivity =
lastFocusedRootTask == null ? null
: lastFocusedRootTask.getTopResumedActivity();
final ActivityRecord.State lastState = next.getState();
mAtmService.updateCpuStats();
ProtoLog.v(WM_DEBUG_STATES, "Moving to RESUMED: %s (in existing)", next);
next.setState(RESUMED, "resumeTopActivity");
// Activity should also be visible if set mLaunchTaskBehind to true (see
// ActivityRecord#shouldBeVisibleIgnoringKeyguard()).
if (shouldBeVisible(next)) {
// We have special rotation behavior when here is some active activity that
// requests specific orientation or Keyguard is locked. Make sure all activity
// visibilities are set correctly as well as the transition is updated if needed
// to get the correct rotation behavior. Otherwise the following call to update
// the orientation may cause incorrect configurations delivered to client as a
// result of invisible window resize.
// TODO: Remove this once visibilities are set correctly immediately when
// starting an activity.
final int originalRelaunchingCount = next.mPendingRelaunchCount;
mRootWindowContainer.ensureVisibilityAndConfig(next, mDisplayContent,
false /* deferResume */);
if (next.mPendingRelaunchCount > originalRelaunchingCount) {
// The activity is scheduled to relaunch, then ResumeActivityItem will be also
// included (see ActivityRecord#relaunchActivityLocked) if it should resume.
next.completeResumeLocked();
return true;
}
}
try {
final IApplicationThread appThread = next.app.getThread();
// Deliver all pending results.
final ArrayList<ResultInfo> a = next.results;
if (a != null) {
final int size = a.size();
if (!next.finishing && size > 0) {
if (DEBUG_RESULTS) {
Slog.v(TAG_RESULTS, "Delivering results to " + next + ": " + a);
}
final ActivityResultItem item = new ActivityResultItem(next.token, a);
mAtmService.getLifecycleManager().scheduleTransactionItem(appThread, item);
}
}
if (next.newIntents != null) {
final NewIntentItem item =
new NewIntentItem(next.token, next.newIntents, true /* resume */);
mAtmService.getLifecycleManager().scheduleTransactionItem(appThread, item);
}
// Well the app will no longer be stopped.
// Clear app token stopped state in window manager if needed.
next.notifyAppResumed();
EventLogTags.writeWmResumeActivity(next.mUserId, System.identityHashCode(next),
next.getTask().mTaskId, next.shortComponentName);
mAtmService.getAppWarningsLocked().onResumeActivity(next);
final int topProcessState = mAtmService.mTopProcessState;
next.app.setPendingUiCleanAndForceProcessStateUpTo(topProcessState);
next.abortAndClearOptionsAnimation();
final ResumeActivityItem resumeActivityItem = new ResumeActivityItem(
next.token, topProcessState, dc.isNextTransitionForward(),
next.shouldSendCompatFakeFocus());
mAtmService.getLifecycleManager().scheduleTransactionItem(
appThread, resumeActivityItem);
ProtoLog.d(WM_DEBUG_STATES, "resumeTopActivity: Resumed %s", next);
} catch (Exception e) {
// Whoops, need to restart this activity!
ProtoLog.v(WM_DEBUG_STATES, "Resume failed; resetting state to %s: "
+ "%s", lastState, next);
next.setState(lastState, "resumeTopActivityInnerLocked");
// lastResumedActivity being non-null implies there is a lastStack present.
if (lastResumedActivity != null) {
lastResumedActivity.setState(RESUMED, "resumeTopActivityInnerLocked");
}
Slog.i(TAG, "Restarting because process died: " + next);
if (!next.hasBeenLaunched) {
next.hasBeenLaunched = true;
} else if (SHOW_APP_STARTING_PREVIEW && lastFocusedRootTask != null
&& lastFocusedRootTask.isTopRootTaskInDisplayArea()) {
next.showStartingWindow(false /* taskSwitch */);
}
mTaskSupervisor.startSpecificActivity(next, true, false);
return true;
}
next.completeResumeLocked();
} else {
// Whoops, need to restart this activity!
if (!next.hasBeenLaunched) {
next.hasBeenLaunched = true;
} else {
if (SHOW_APP_STARTING_PREVIEW) {
next.showStartingWindow(false /* taskSwich */);
}
if (DEBUG_SWITCH) Slog.v(TAG_SWITCH, "Restarting: " + next);
}
ProtoLog.d(WM_DEBUG_STATES, "resumeTopActivity: Restarting %s", next);
mTaskSupervisor.startSpecificActivity(next, true, true); // 1
}
return true;
}
代码1处ActivityTaskSupervisor对象调用startSpecificActivity方法启动Activity，源码如下：
void startSpecificActivity(ActivityRecord r, boolean andResume, boolean checkConfig) {
// Is this activity's application already running?
final WindowProcessController wpc =
mService.getProcessController(r.processName, r.info.applicationInfo.uid);
boolean knownToBeDead = false;
if (wpc != null && wpc.hasThread()) {
try {
realStartActivityLocked(r, wpc, andResume, checkConfig); // 1
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.
knownToBeDead = true;
// Remove the process record so it won't be considered as alive.
mService.mProcessNames.remove(wpc.mName, wpc.mUid);
mService.mProcessMap.remove(wpc.getPid());
} else if (ActivityTaskManagerService.isSdkSandboxActivityIntent(
mService.mContext, r.intent)) {
Slog.e(TAG, "Abort sandbox activity launching as no sandbox process to host it.");
r.finishIfPossible("No sandbox process for the activity", false /* oomAdj */);
r.launchFailed = true;
r.detachFromProcess();
return;
}
r.notifyUnknownVisibilityLaunchedForKeyguardTransition();
final boolean isTop = andResume && r.isTopRunningActivity();
mService.startProcessAsync(r, knownToBeDead, isTop,
isTop ? HostingRecord.HOSTING_TYPE_TOP_ACTIVITY
: HostingRecord.HOSTING_TYPE_ACTIVITY);
}
代码1处ActivityTaskSupervisor对象调用realStartActivityLocked方法启动Activity，源码如下：
boolean realStartActivityLocked(ActivityRecord r, WindowProcessController proc, boolean andResume, boolean checkConfig) throws RemoteException {
if (!mRootWindowContainer.allPausedActivitiesComplete()) {
// While there are activities pausing we skipping starting any new activities until
// pauses are complete. NOTE: that we also do this for activities that are starting in
// the paused state because they will first be resumed then paused on the client side.
ProtoLog.v(WM_DEBUG_STATES,
"realStartActivityLocked: Skipping start of r=%s some activities pausing...",
r);
return false;
}
final Task task = r.getTask();
if (andResume) {
// Try pausing the existing resumed activity in the Task if any.
if (task.pauseActivityIfNeeded(r, "realStart")) {
return false;
}
final TaskFragment taskFragment = r.getTaskFragment();
if (taskFragment != null && taskFragment.getResumedActivity() != null) {
if (taskFragment.startPausing(mUserLeaving, false /* uiSleeping */, r,
"realStart")) {
return false;
}
}
}
final Task rootTask = task.getRootTask();
beginDeferResume();
// The LaunchActivityItem also contains process configuration, so the configuration change
// from WindowProcessController#setProcess can be deferred. The major reason is that if
// the activity has FixedRotationAdjustments, it needs to be applied with configuration.
// In general, this reduces a binder transaction if process configuration is changed.
proc.pauseConfigurationDispatch();
try {
// schedule launch ticks to collect information about slow apps.
r.startLaunchTickingLocked();
r.lastLaunchTime = SystemClock.uptimeMillis();
r.setProcess(proc);
// Ensure activity is allowed to be resumed after process has set.
if (andResume && !r.canResumeByCompat()) {
andResume = false;
}
r.notifyUnknownVisibilityLaunchedForKeyguardTransition();
// 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) {
// Deferring resume here because we're going to launch new activity shortly.
// We don't want to perform a redundant launch of the same record while ensuring
// configurations and trying to resume top activity of focused root task.
mRootWindowContainer.ensureVisibilityAndConfig(r, r.mDisplayContent, true /* deferResume */);
}
if (mKeyguardController.checkKeyguardVisibility(r) && r.allowMoveToFront()) {
// We only set the visibility to true if the activity is not being launched in
// background, and is allowed to be visible based on keyguard state. This avoids
// setting this into motion in window manager that is later cancelled due to later
// calls to ensure visible activities that set visibility back to false.
r.setVisibility(true);
}
final int applicationInfoUid =
(r.info.applicationInfo != null) ? r.info.applicationInfo.uid : -1;
if ((r.mUserId != proc.mUserId) || (r.info.applicationInfo.uid != applicationInfoUid)) {
Slog.wtf(TAG,
"User ID for activity changing for " + r
+ " appInfo.uid=" + r.info.applicationInfo.uid
+ " info.ai.uid=" + applicationInfoUid
+ " old=" + r.app + " new=" + proc);
}
// Send the controller to client if the process is the first time to launch activity.
// So the client can save binder transactions of getting the controller from activity
// task manager service.
final IActivityClientController activityClientController =
proc.hasEverLaunchedActivity() ? null : mService.mActivityClientController;
r.launchCount++;
if (DEBUG_ALL) Slog.v(TAG, "Launching: " + r);
final LockTaskController lockTaskController = mService.getLockTaskController();
if (task.mLockTaskAuth == LOCK_TASK_AUTH_LAUNCHABLE
|| task.mLockTaskAuth == LOCK_TASK_AUTH_LAUNCHABLE_PRIV
|| (task.mLockTaskAuth == LOCK_TASK_AUTH_ALLOWLISTED
&& lockTaskController.getLockTaskModeState()
== LOCK_TASK_MODE_LOCKED)) {
lockTaskController.startLockTaskMode(task, false, 0 /* blank UID */);
}
try {
if (!proc.hasThread()) {
throw new RemoteException();
}
List<ResultInfo> results = null;
List<ReferrerIntent> newIntents = null;
if (andResume) {
// We don't need to deliver new intents and/or set results if activity is going
// to pause immediately after launch.
results = r.results;
newIntents = r.newIntents;
}
if (DEBUG_SWITCH) Slog.v(TAG_SWITCH,
"Launching: " + r + " savedState=" + r.getSavedState()
+ " with results=" + results + " newIntents=" + newIntents
+ " andResume=" + andResume);
EventLogTags.writeWmRestartActivity(r.mUserId, System.identityHashCode(r),
task.mTaskId, r.shortComponentName);
updateHomeProcessIfNeeded(r);
mService.getPackageManagerInternalLocked().notifyPackageUse(
r.intent.getComponent().getPackageName(), NOTIFY_PACKAGE_USE_ACTIVITY);
mService.getAppWarningsLocked().onStartActivity(r);
final Configuration procConfig = proc.prepareConfigurationForLaunchingActivity();
final Configuration overrideConfig = r.getMergedOverrideConfiguration();
r.setLastReportedConfiguration(procConfig, overrideConfig);
final ActivityWindowInfo activityWindowInfo = r.getActivityWindowInfo();
r.setLastReportedActivityWindowInfo(activityWindowInfo);
logIfTransactionTooLarge(r.intent, r.getSavedState());
final TaskFragment organizedTaskFragment = r.getOrganizedTaskFragment();
if (organizedTaskFragment != null) {
// Sending TaskFragmentInfo to client to ensure the info is updated before
// the activity creation.
mService.mTaskFragmentOrganizerController.dispatchPendingInfoChangedEvent(
organizedTaskFragment);
}
// Create activity launch transaction.
final boolean isTransitionForward = r.isTransitionForward();
final IBinder fragmentToken = r.getTaskFragment().getFragmentToken();
final int deviceId = getDeviceIdForDisplayId(r.getDisplayId());
final LaunchActivityItem launchActivityItem = new LaunchActivityItem(r.token, r.intent, System.identityHashCode(r), r.info,
procConfig, overrideConfig, deviceId,
r.getFilteredReferrer(r.launchedFromPackage), task.voiceInteractor,
proc.getReportedProcState(), r.getSavedState(), r.getPersistentSavedState(),
results, newIntents, r.takeSceneTransitionInfo(), isTransitionForward,
proc.createProfilerInfoIfNeeded(), r.assistToken, activityClientController,
r.shareableActivityToken, r.getLaunchedFromBubble(), fragmentToken,
r.initialCallerInfoAccessToken, activityWindowInfo);
// Set desired final state.
final ActivityLifecycleItem lifecycleItem;
if (andResume) {
lifecycleItem = new ResumeActivityItem(r.token, isTransitionForward,
r.shouldSendCompatFakeFocus());
} else if (r.isVisibleRequested()) {
lifecycleItem = new PauseActivityItem(r.token);
} else {
lifecycleItem = new StopActivityItem(r.token);
}
// Schedule transaction.
if (shouldDispatchLaunchActivityItemIndependently(r.info.packageName, r.getUid())) {
// LaunchActivityItem has @UnsupportedAppUsage usages.
// Guard with targetSDK on Android 15+.
// To not bundle the transaction, dispatch the pending before schedule new
// transaction.
mService.getLifecycleManager().dispatchPendingTransaction(proc.getThread());
}
mService.getLifecycleManager().scheduleTransactionAndLifecycleItems(
proc.getThread(), launchActivityItem, lifecycleItem,
// Immediately dispatch the transaction, so that if it fails, the server can
// restart the process and retry now.
true /* shouldDispatchImmediately */); // 1
if (procConfig.seq > mRootWindowContainer.getConfiguration().seq) {
// If the seq is increased, there should be something changed (e.g. registered
// activity configuration).
proc.setLastReportedConfiguration(procConfig);
}
if ((proc.mInfo.privateFlags & ApplicationInfo.PRIVATE_FLAG_CANT_SAVE_STATE) != 0
&& mService.mHasHeavyWeightFeature) {
// 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 (proc.mName.equals(proc.mInfo.packageName)) {
if (mService.mHeavyWeightProcess != null
&& mService.mHeavyWeightProcess != proc) {
Slog.w(TAG, "Starting new heavy weight process " + proc
+ " when already running "
+ mService.mHeavyWeightProcess);
}
mService.setHeavyWeightProcess(r);
}
}
} 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);
proc.appDied("2nd-crash");
r.finishIfPossible("2nd-crash", false /* oomAdj */);
return false;
}
// This is the first time we failed -- restart process and
// retry.
r.launchFailed = true;
r.detachFromProcess();
throw e;
}
} finally {
endDeferResume();
proc.resumeConfigurationDispatch();
}
r.launchFailed = false;
// TODO(lifecycler): Resume or pause requests are done as part of launch transaction,
// so updating the state should be done accordingly.
if (andResume && readyToResume()) {
// As part of the process of launching, ActivityThread also performs
// a resume.
r.setState(RESUMED, "realStartActivityLocked");
r.completeResumeLocked();
} else if (r.isVisibleRequested()) {
// 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.
ProtoLog.v(WM_DEBUG_STATES, "Moving to PAUSED: %s "
+ "(starting in paused state)", r);
r.setState(PAUSED, "realStartActivityLocked");
mRootWindowContainer.executeAppTransitionForAllDisplay();
} else {
// This activity is starting while invisible, so it should be stopped.
r.setState(STOPPING, "realStartActivityLocked");
}
// Perform OOM scoring after the activity state is set, so the process can be updated with
// the latest state.
proc.onStartActivity(mService.mTopProcessState, r.info); // 2
// 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 (mRootWindowContainer.isTopDisplayFocusedRootTask(rootTask)) {
mService.getActivityStartController().startSetupActivity(); // 3
}
// Update any services we are bound to that might care about whether
// their client may have activities.
if (r.app != null) {
r.app.updateServiceConnectionActivities();
}
return true;
}
在1处真正启动Activity,
mService是一个ActivityTaskManagerService类型的对象。
mService.getLifecycleManager()方法返回的是一个ClientLifecycleManager类型的对象。
scheduleTransactionAndLifecycleItems源码如下：
frameworks/base/services/core/java/com/android/server/wm/ClientLifecycleManager.java
void scheduleTransactionAndLifecycleItems(@NonNull IApplicationThread client,
@NonNull ClientTransactionItem transactionItem,
@NonNull ActivityLifecycleItem lifecycleItem,
boolean shouldDispatchImmediately) throws RemoteException {
// Wait until RootWindowContainer#performSurfacePlacementNoTrace to dispatch all pending
// transactions at once.
final ClientTransaction clientTransaction = getOrCreatePendingTransaction(client);
clientTransaction.addTransactionItem(transactionItem);
clientTransaction.addTransactionItem(lifecycleItem);
onClientTransactionItemScheduled(clientTransaction, shouldDispatchImmediately);
}
scheduleTransactionAndLifecycleItems方法又调用了onClientTransactionItemScheduled方法，其源码如下:
frameworks/base/services/core/java/com/android/server/wm/ClientLifecycleManager.java
/** Must only be called with WM lock. */
private void onClientTransactionItemScheduled(
@NonNull ClientTransaction clientTransaction,
boolean shouldDispatchImmediately) throws RemoteException {
if (shouldDispatchImmediately || shouldDispatchPendingTransactionsImmediately()) {
// Dispatch the pending transaction immediately.
mPendingTransactions.remove(clientTransaction.getClient().asBinder());
scheduleTransaction(clientTransaction);
}
}
/**
* Schedules a transaction, which may consist of multiple callbacks and a lifecycle request.
* @param transaction A sequence of client transaction items.
* @throws RemoteException
*
* @see ClientTransaction
*/
@VisibleForTesting
void scheduleTransaction(@NonNull ClientTransaction transaction) throws RemoteException {
final IApplicationThread client = transaction.getClient();
try {
transaction.schedule(); // 1
} catch (RemoteException e) {
Slog.w(TAG, "Failed to deliver transaction for " + client + "\ntransaction=" + transaction);
throw e;
}
}
transaction的ClientTransaction的源码如下：
frameworks/base/core/java/android/app/servertransaction/ClientTransaction.java
/**
* Schedule the transaction after it was initialized. It will be send to client and all its
* individual parts will be applied in the following sequence:
* 1. The client calls {@link #preExecute(ClientTransactionHandler)}, which triggers all work
* that needs to be done before actually scheduling the transaction for callbacks and
* lifecycle state request.
* 2. The transaction message is scheduled.
* 3. The client calls {@link TransactionExecutor#execute(ClientTransaction)}, which executes
* all callbacks and necessary lifecycle transitions.
*/
public void schedule() throws RemoteException {
mClient.scheduleTransaction(this);
}
mClient是IApplicationThread代理对象
frameworks/base/core/java/android/app/IApplicationThread.aidl
void scheduleTransaction(in ClientTransaction transaction);
则服务端进程调用链完成，现在回到App进程中。
ApplicationThread是ActivityThread的内部类，我们来看下scheduleTransaction方法的源码。
frameworks/base/core/java/android/app/ActivityThread.java
/**
* This manages the execution of the main thread in an
* application process, scheduling and executing activities,
* broadcasts, and other operations on it as the activity
* manager requests.
*
* {@hide}
*/
public final class ActivityThread extends ClientTransactionHandler implements ActivityThreadInternal {
private class ApplicationThread extends IApplicationThread.Stub{
@Override
public void scheduleTransaction(ClientTransaction transaction) throws RemoteException {
ActivityThread.this.scheduleTransaction(transaction); // 1
}
}
// 真正的实现方法
void sendMessage(int what, Object obj) {
sendMessage(what, obj, 0, 0, false);
}
private void sendMessage(int what, Object obj, int arg1) {
sendMessage(what, obj, arg1, 0, false);
}
private void sendMessage(int what, Object obj, int arg1, int arg2) {
sendMessage(what, obj, arg1, arg2, false);
}
private void sendMessage(int what, Object obj, int arg1, int arg2, boolean async) {
if (DEBUG_MESSAGES) {
Slog.v(TAG,
"SCHEDULE " + what + " " + mH.codeToString(what) + ": " + arg1 + " / " + obj);
}
Message msg = Message.obtain();
msg.what = what;
msg.obj = obj;
msg.arg1 = arg1;
msg.arg2 = arg2;
if (async) {
msg.setAsynchronous(true);
}
mH.sendMessage(msg); // 2
}
}
1处方法调用了ClientTransactionHandler对象的scheduleTransaction方法，其源码如下：
frameworks/base/core/java/android/app/ClientTransactionHandler.java
// Schedule phase related logic and handlers.
/** Prepare and schedule transaction for execution. */
void scheduleTransaction(ClientTransaction transaction) {
transaction.preExecute(this);
sendMessage(ActivityThread.H.EXECUTE_TRANSACTION, transaction);
}
如代码2处，
ClientTransactionHandler对象的sendMessage方法在ActivityThread中实现，最终调用了，ActivityThread的内部类H类型的对象mH的sendMessage方法。我们来看一下EXECUTE_TRANSACTION常量对应的逻辑源码：
frameworks/base/core/java/android/app/ActivityThread.java
case EXECUTE_TRANSACTION:
final ClientTransaction transaction = (ClientTransaction) msg.obj;
final ClientTransactionListenerController controller =
ClientTransactionListenerController.getInstance();
controller.onClientTransactionStarted();
try {
mTransactionExecutor.execute(transaction); // 1
} finally {
controller.onClientTransactionFinished();
}
break;
private final TransactionExecutor mTransactionExecutor = new TransactionExecutor(this);
由源码可知mTransactionExecutor是一个TransactionExecutor类型的对象，其execute方法源码如下：
frameworks/base/core/java/android/app/servertransaction/TransactionExecutor.java
/**
* Resolve transaction.
* First all callbacks will be executed in the order they appear in the list. If a callback
* requires a certain pre- or post-execution state, the client will be transitioned accordingly.
* Then the client will cycle to the final lifecycle state if provided. Otherwise, it will
* either remain in the initial state, or last state needed by a callback.
*/
public void execute(@NonNull ClientTransaction transaction) {
if (DEBUG_RESOLVER) {
Slog.d(TAG, tId(transaction) + "Start resolving transaction");
Slog.d(TAG, transactionToString(transaction, mTransactionHandler));
}
Trace.traceBegin(Trace.TRACE_TAG_WINDOW_MANAGER, "clientTransactionExecuted");
try {
executeTransactionItems(transaction); // 1
} catch (Exception e) {
Slog.e(TAG, "Failed to execute the transaction: "
+ transactionToString(transaction, mTransactionHandler));
throw e;
} finally {
Trace.traceEnd(Trace.TRACE_TAG_WINDOW_MANAGER);
}
mPendingActions.clear();
if (DEBUG_RESOLVER) Slog.d(TAG, tId(transaction) + "End resolving transaction");
}
/** Cycles through all transaction items and execute them at proper times. */
@VisibleForTesting
public void executeTransactionItems(@NonNull ClientTransaction transaction) {
final List<ClientTransactionItem> items = transaction.getTransactionItems();
final int size = items.size();
for (int i = 0; i < size; i++) {
final ClientTransactionItem item = items.get(i);
if (item.isActivityLifecycleItem()) {
executeLifecycleItem(transaction, (ActivityLifecycleItem) item); // 2
} else {
executeNonLifecycleItem(transaction, item,
shouldExcludeLastLifecycleState(items, i));
}
}
}
private void executeLifecycleItem(@NonNull ClientTransaction transaction,
@NonNull ActivityLifecycleItem lifecycleItem) {
final IBinder token = lifecycleItem.getActivityToken();
final ActivityClientRecord r = mTransactionHandler.getActivityClient(token);
if (DEBUG_RESOLVER) {
Slog.d(TAG, tId(transaction) + "Resolving lifecycle state: "
+ lifecycleItem + " for activity: "
+ getShortActivityName(token, mTransactionHandler));
}
if (r == null) {
if (mTransactionHandler.getActivitiesToBeDestroyed().get(token) == lifecycleItem) {
// Always cleanup for destroy item.
lifecycleItem.postExecute(mTransactionHandler, mPendingActions);
}
// Ignore requests for non-existent client records for now.
return;
}
// Cycle to the state right before the final requested state.
cycleToPath(r, lifecycleItem.getTargetState(), true /* excludeLastState */, transaction); // 3
// Execute the final transition with proper parameters.
lifecycleItem.execute(mTransactionHandler, mPendingActions);
lifecycleItem.postExecute(mTransactionHandler, mPendingActions);
}
/**
* Transition the client between states with an option not to perform the last hop in the
* sequence. This is used when resolving lifecycle state request, when the last transition must
* be performed with some specific parameters.
*/
private void cycleToPath(ActivityClientRecord r, int finish, boolean excludeLastState,
ClientTransaction transaction) {
final int start = r.getLifecycleState();
if (DEBUG_RESOLVER) {
Slog.d(TAG, tId(transaction) + "Cycle activity: "
+ getShortActivityName(r.token, mTransactionHandler)
+ " from: " + getStateName(start) + " to: " + getStateName(finish)
+ " excludeLastState: " + excludeLastState);
}
final IntArray path = mHelper.getLifecyclePath(start, finish, excludeLastState);
performLifecycleSequence(r, path, transaction); // 4
}
/** Transition the client through previously initialized state sequence. */
private void performLifecycleSequence(ActivityClientRecord r, IntArray path,
ClientTransaction transaction) {
final int size = path.size();
for (int i = 0, state; i < size; i++) {
state = path.get(i);
if (DEBUG_RESOLVER) {
Slog.d(TAG, tId(transaction) + "Transitioning activity: "
+ getShortActivityName(r.token, mTransactionHandler)
+ " to state: " + getStateName(state));
}
switch (state) {
case ON_CREATE: // 5
mTransactionHandler.handleLaunchActivity(r, mPendingActions,
Context.DEVICE_ID_INVALID, null /* customIntent */);
break;
case ON_START:
mTransactionHandler.handleStartActivity(r, mPendingActions,
null /* sceneTransitionInfo */);
break;
case ON_RESUME:
mTransactionHandler.handleResumeActivity(r, false /* finalStateRequest */,
r.isForward, false /* shouldSendCompatFakeFocus */,
"LIFECYCLER_RESUME_ACTIVITY");
break;
case ON_PAUSE:
mTransactionHandler.handlePauseActivity(r, false /* finished */,
false /* userLeaving */,
false /* autoEnteringPip */, mPendingActions,
"LIFECYCLER_PAUSE_ACTIVITY");
break;
case ON_STOP:
mTransactionHandler.handleStopActivity(r,
mPendingActions, false /* finalStateRequest */,
"LIFECYCLER_STOP_ACTIVITY");
break;
case ON_DESTROY:
mTransactionHandler.handleDestroyActivity(r, false /* finishing */,
false /* getNonConfigInstance */,
"performLifecycleSequence. cycling to:" + path.get(size - 1));
break;
case ON_RESTART:
mTransactionHandler.performRestartActivity(r, false /* start */);
break;
default:
throw new IllegalArgumentException("Unexpected lifecycle state: " + state);
}
}
}
代码5处执行了mTransactionHandler.handleLaunchActivity()方法，
mTransactionHandler是lientTransactionHandler类型的对象，其方法handleLaunchActivity源码如下所示:
frameworks/base/core/java/android/app/ClientTransactionHandler.java
public abstract Activity handleLaunchActivity(@NonNull ActivityClientRecord r, PendingTransactionActions pendingActions, int deviceId, Intent customIntent);
最终是由其子类ActivityThread实现，其源码如下：
frameworks/base/core/java/android/app/ActivityThread.java
/**
* Extended implementation of activity launch. Used when server requests a launch or relaunch.
*/
@Override
public Activity handleLaunchActivity(ActivityClientRecord r,
PendingTransactionActions pendingActions, int deviceId, 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 and resource paths.
applyPendingApplicationInfoChanges(r.activityInfo.packageName);
mConfigurationController.handleConfigurationChanged(null, null);
updateDeviceIdForNonUIContexts(deviceId);
if (localLOGV) Slog.v(
TAG, "Handling launch of " + r);
// Initialize before creating the activity
if (ThreadedRenderer.sRendererEnabled
&& (r.activityInfo.flags & ActivityInfo.FLAG_HARDWARE_ACCELERATED) != 0) {
HardwareRenderer.preload();
}
WindowManagerGlobal.initialize();
// Hint the GraphicsEnvironment that an activity is launching on the process.
GraphicsEnvironment.hintActivityLaunch();
final Activity a = performLaunchActivity(r, customIntent); // 1
if (a != null) {
r.createdConfig = new Configuration(mConfigurationController.getConfiguration());
reportSizeConfigurations(r);
if (!r.activity.mFinished && pendingActions != null) {
pendingActions.setOldState(r.state);
pendingActions.setRestoreInstanceState(true);
pendingActions.setCallOnPostCreate(true);
}
// Trigger ActivityWindowInfo callback if first launch or change from relaunch.
handleActivityWindowInfoChanged(r);
} else {
// If there was an error, for any reason, tell the activity manager to stop us.
ActivityClient.getInstance().finishActivity(r.token, Activity.RESULT_CANCELED,
null /* resultData */, Activity.DONT_FINISH_TASK_WITH_ACTIVITY);
}
return a;
}
/** Core implementation of activity launch. */
private Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {
ActivityInfo aInfo = r.activityInfo;
if (getInstrumentation() != null
&& getInstrumentation().getContext() != null
&& getInstrumentation().getContext().getApplicationInfo() != null
&& getInstrumentation().isSdkSandboxAllowedToStartActivities()) {
// Activities launched from CTS-in-sandbox tests use a customized ApplicationInfo. See
// also {@link SdkSandboxManagerLocal#getSdkSandboxApplicationInfoForInstrumentation}.
r.packageInfo =
getPackageInfo(
getInstrumentation().getContext().getApplicationInfo(),
mCompatibilityInfo,
Context.CONTEXT_INCLUDE_CODE);
} else if (r.packageInfo == null) {
r.packageInfo = getPackageInfo(aInfo.applicationInfo, mCompatibilityInfo,
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);
}
boolean isSandboxActivityContext =
sandboxActivitySdkBasedContext()
&& SdkSandboxActivityAuthority.isSdkSandboxActivityIntent(
mSystemContext, r.intent);
boolean isSandboxedSdkContextUsed = false;
ContextImpl activityBaseContext;
if (isSandboxActivityContext) {
activityBaseContext = createBaseContextForSandboxActivity(r);
if (activityBaseContext == null) {
// Failed to retrieve the SDK based sandbox activity context, falling back to the
// app based context.
activityBaseContext = createBaseContextForActivity(r);
} else {
isSandboxedSdkContextUsed = true;
}
} else {
activityBaseContext = createBaseContextForActivity(r);
}
Activity activity = null;
try {
java.lang.ClassLoader cl;
if (isSandboxedSdkContextUsed) {
// In case of sandbox activity, the context refers to the an SDK with no visibility
// on the SandboxedActivity java class, the App context should be used instead.
cl = activityBaseContext.getApplicationContext().getClassLoader();
} else {
cl = activityBaseContext.getClassLoader();
}
activity = mInstrumentation.newActivity(
cl, component.getClassName(), r.intent); // 2
StrictMode.incrementExpectedActivityCount(activity.getClass());
r.intent.setExtrasClassLoader(cl);
r.intent.prepareToEnterProcess(isProtectedComponent(r.activityInfo),
activityBaseContext.getAttributionSource());
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.makeApplicationInner(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());
// updatePendingActivityConfiguration() reads from mActivities to update
// ActivityClientRecord which runs in a different thread. Protect modifications to
// mActivities to avoid race.
synchronized (mResourcesManager) {
mActivities.put(r.token, r);
}
if (activity != null) {
CharSequence title =
r.activityInfo.loadLabel(activityBaseContext.getPackageManager());
Configuration config =
new Configuration(mConfigurationController.getCompatConfiguration());
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;
}
// Activity resources must be initialized with the same loaders as the
// application context.
activityBaseContext.getResources().addLoaders(
app.getResources().getLoaders().toArray(new ResourcesLoader[0]));
activityBaseContext.setOuterContext(activity);
activity.attach(activityBaseContext, 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.activityConfigCallback,
r.assistToken, r.shareableActivityToken, r.initialCallerInfoAccessToken);
if (customIntent != null) {
activity.mIntent = customIntent;
}
r.lastNonConfigurationInstances = null;
checkAndBlockForNetworkAccess();
activity.mStartedActivity = false;
int theme = r.activityInfo.getThemeResource();
if (theme != 0) {
activity.setTheme(theme);
}
if (r.mSceneTransitionInfo != null) {
activity.mSceneTransitionInfo = r.mSceneTransitionInfo;
r.mSceneTransitionInfo = null;
}
activity.mLaunchedFromBubble = r.mLaunchedFromBubble;
activity.mCalled = false;
// Assigning the activity to the record before calling onCreate() allows
// ActivityThread#getActivity() lookup for the callbacks triggered from
// ActivityLifecycleCallbacks#onActivityCreated() or
// ActivityLifecycleCallback#onActivityPostCreated().
r.activity = activity;
if (r.isPersistable()) {
mInstrumentation.callActivityOnCreate(activity, r.state, r.persistentState);
} else {
mInstrumentation.callActivityOnCreate(activity, r.state); // 1
}
if (!activity.mCalled) {
throw new SuperNotCalledException(
"Activity " + r.intent.getComponent().toShortString() +
" did not call through to super.onCreate()");
}
r.mLastReportedWindowingMode = config.windowConfiguration.getWindowingMode();
}
r.setState(ON_CREATE);
} 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;
}
代码2处mInstrumentation是一个Instrumentation类型的对象，其调用了newActivity方法，其源码如下：
frameworks/base/core/java/android/app/Instrumentation.java
public Activity newActivity(Class<?> clazz, Context context,
IBinder token, Application application, Intent intent, ActivityInfo info,
CharSequence title, Activity parent, String id,
Object lastNonConfigurationInstance) throws InstantiationException,
IllegalAccessException {
Activity activity = (Activity)clazz.newInstance();
ActivityThread aThread = null;
// Activity.attach expects a non-null Application Object.
if (application == null) {
application = new Application();
}
activity.attach(context, aThread, this, token, 0 /* ident */, application, intent,
info, title, parent, id,
(Activity.NonConfigurationInstances)lastNonConfigurationInstance,
new Configuration(), null /* referrer */, null /* voiceInteractor */,
null /* window */, null /* activityCallback */, null /* assistToken */,
null /* shareableActivityToken */, null /* initialCallerInfoAccessToken */);
return activity;
}
代码1处调用了Activity的onCreate方法,
frameworks/base/core/java/android/app/Instrumentation.java
/**
* Perform calling of an activity's {@link Activity#onCreate}
* method. The default implementation simply calls through to that method.
*
* @param activity The activity being created.
* @param icicle The previously frozen state (or null) to pass through to onCreate().
*/
public void callActivityOnCreate(Activity activity, Bundle icicle) {
prePerformCreate(activity);
activity.performCreate(icicle); // 1
postPerformCreate(activity);
}
1处代码最终调用了Activity对象的onCreate方法，其源码如下：
@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
final void performCreate(Bundle icicle, PersistableBundle persistentState) {
if (Trace.isTagEnabled(Trace.TRACE_TAG_WINDOW_MANAGER)) {
Trace.traceBegin(Trace.TRACE_TAG_WINDOW_MANAGER, "performCreate:"
+ mComponent.getClassName());
}
dispatchActivityPreCreated(icicle);
mCanEnterPictureInPicture = true;
// initialize mIsInMultiWindowMode and mIsInPictureInPictureMode before onCreate
final int windowingMode = getResources().getConfiguration().windowConfiguration
.getWindowingMode();
mIsInMultiWindowMode = inMultiWindowMode(windowingMode);
mIsInPictureInPictureMode = windowingMode == WINDOWING_MODE_PINNED;
mShouldDockBigOverlays = getResources().getBoolean(R.bool.config_dockBigOverlayWindows);
restoreHasCurrentPermissionRequest(icicle);
final long startTime = SystemClock.uptimeMillis();
if (persistentState != null) {
onCreate(icicle, persistentState);
} else {
onCreate(icicle); // 1
}
final long duration = SystemClock.uptimeMillis() - startTime;
EventLogTags.writeWmOnCreateCalled(mIdent, getComponentName().getClassName(),
"performCreate", duration);
mActivityTransitionState.readState(icicle);
mVisibleFromClient = !mWindow.getWindowStyle().getBoolean(
com.android.internal.R.styleable.Window_windowNoDisplay, false);
mFragments.dispatchActivityCreated();
mActivityTransitionState.setEnterSceneTransitionInfo(this, getSceneTransitionInfo());
dispatchActivityPostCreated(icicle);
Trace.traceEnd(Trace.TRACE_TAG_WINDOW_MANAGER);
}
至此从startActivty至Activity对象的onCreate方法执行的调用链全部分析完成。
有什么不足的地方还望大家批评指正，提出宝贵意见，我一定慢慢完善。
关联文章
// TODO
1. 启动一个未启动的App进程的Activity会发生什么？
2. 在LauncherActivity界面点击应用图标会发生什么？
来源链接：https://www.cnblogs.com/zshsboke/p/18679838/startActivity01
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