Activity启动流程-2.3

Android 系统源代码情景分析，学习记录
情景是启动未启动的应用的Activity

startActivity.drawio.png

Activity#startActivity

    @Override
    public void startActivity(Intent intent) {
        startActivityForResult(intent, -1);
    }

    public void startActivityForResult(Intent intent, int requestCode) {
        if (mParent == null) {
            Instrumentation.ActivityResult ar =
                mInstrumentation.execStartActivity(
                    this, mMainThread.getApplicationThread(), mToken, this,
                    intent, requestCode);
            if (ar != null) {
                mMainThread.sendActivityResult(
                    mToken, mEmbeddedID, requestCode, ar.getResultCode(),
                    ar.getResultData());
            }
        }
    }

Instrumentation#execStartActivity

    public ActivityResult execStartActivity(
        Context who, IBinder contextThread, IBinder token, Activity target,
        Intent intent, int requestCode) {
        IApplicationThread whoThread = (IApplicationThread) contextThread;

        try {
            int result = ActivityManagerNative.getDefault()
                .startActivity(whoThread, intent,
                        intent.resolveTypeIfNeeded(who.getContentResolver()),
                        null, 0, token, target != null ? target.mEmbeddedID : null,
                        requestCode, false, false);
            checkStartActivityResult(result, intent);
        } catch (RemoteException e) {
        }
        return null;
    }

ActivityManagerService#startActivity

    public final int startActivity(IApplicationThread caller,
            Intent intent, String resolvedType, Uri[] grantedUriPermissions,
            int grantedMode, IBinder resultTo,
            String resultWho, int requestCode, boolean onlyIfNeeded,
            boolean debug) {
            // grantedUriPermissions = null; onlyIfNeeded = false;
            // debug = false; grantedMode = 0; 
        return mMainStack.startActivityMayWait(caller, intent, resolvedType,
                grantedUriPermissions, grantedMode, resultTo, resultWho,
                requestCode, onlyIfNeeded, debug, null, null);
    }

ActivityStack#startActivityMayWait

    final int startActivityMayWait(IApplicationThread caller,
            Intent intent, String resolvedType, Uri[] grantedUriPermissions,
            int grantedMode, IBinder resultTo,
            String resultWho, int requestCode, boolean onlyIfNeeded,
            boolean debug, WaitResult outResult, Configuration config) {
            // grantedUriPermissions = null; 
            // outResult = null ; config = null
            // onlyIfNeeded = false;  debug = false;
        boolean componentSpecified = intent.getComponent() != null;
        
        // Don't modify the client's object!
        intent = new Intent(intent);

        // Collect information about the target of the Intent.
        ActivityInfo aInfo;
        try {
            ResolveInfo rInfo =
                AppGlobals.getPackageManager().resolveIntent(
                        intent, resolvedType,
                        PackageManager.MATCH_DEFAULT_ONLY
                        | ActivityManagerService.STOCK_PM_FLAGS);
            aInfo = rInfo != null ? rInfo.activityInfo : null;
        } catch (RemoteException e) {
            aInfo = null;
        }


        synchronized (mService) {
            final long origId = Binder.clearCallingIdentity();

            int res = startActivityLocked(caller, intent, resolvedType,
                    grantedUriPermissions, grantedMode, aInfo,
                    resultTo, resultWho, requestCode, callingPid, callingUid,
                    onlyIfNeeded, componentSpecified);
            
            Binder.restoreCallingIdentity(origId);

            return res;
        }
    }

ActivityStack#startActivityLocked

    final int startActivityLocked(IApplicationThread caller,
            Intent intent, String resolvedType,
            Uri[] grantedUriPermissions,
            int grantedMode, ActivityInfo aInfo, IBinder resultTo,
            String resultWho, int requestCode,
            int callingPid, int callingUid, boolean onlyIfNeeded,
            boolean componentSpecified) {
            // grantedUriPermissions = null; 
            // outResult = null ; config = null
            // onlyIfNeeded = false;  debug = false;
            // grantedMode = 0;

        int err = START_SUCCESS;

        ProcessRecord callerApp = null;
        if (caller != null) {
            callerApp = mService.getRecordForAppLocked(caller);
            if (callerApp != null) {
                callingPid = callerApp.pid;
                callingUid = callerApp.info.uid;
            } else {
                
            }
        }

        ActivityRecord sourceRecord = null;
        ActivityRecord resultRecord = null;
        if (resultTo != null) {
            int index = indexOfTokenLocked(resultTo);
            if (DEBUG_RESULTS) Slog.v(
                TAG, "Sending result to " + resultTo + " (index " + index + ")");
            if (index >= 0) {
                sourceRecord = (ActivityRecord)mHistory.get(index);
                if (requestCode >= 0 && !sourceRecord.finishing) {
                    resultRecord = sourceRecord;
                }
            }
        }

        
        ActivityRecord r = new ActivityRecord(mService, this, callerApp, callingUid,
                intent, resolvedType, aInfo, mService.mConfiguration,
                resultRecord, resultWho, requestCode, componentSpecified);
        
        return startActivityUncheckedLocked(r, sourceRecord,
                grantedUriPermissions, grantedMode, onlyIfNeeded, true);
    }

ActivityStack#startActivityUncheckedLocked

    final int startActivityUncheckedLocked(ActivityRecord r,
            ActivityRecord sourceRecord, Uri[] grantedUriPermissions,
            int grantedMode, boolean onlyIfNeeded, boolean doResume) {
            // grantedUriPermissions = null; grantedMode = 0; 
            // onlyIfNeeded = false; doResume = true;
        final Intent intent = r.intent;
        final int callingUid = r.launchedFromUid;
        
        int launchFlags = intent.getFlags();
        
        ActivityRecord notTop = (launchFlags&Intent.FLAG_ACTIVITY_PREVIOUS_IS_TOP)
                != 0 ? r : null;

        // 省略代码：是否需要 Intent.FLAG_ACTIVITY_NEW_TASK

        boolean addingToTask = false;

        // 确定要启动Activity的task
        if (r.packageName != null) {
            // 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.
            ActivityRecord top = topRunningNonDelayedActivityLocked(notTop);
            if (top != null && r.resultTo == null) {
                if (top.realActivity.equals(r.realActivity)) {
                    if (top.app != null && top.app.thread != null) {
                        if ((launchFlags&Intent.FLAG_ACTIVITY_SINGLE_TOP) != 0
                            || r.launchMode == ActivityInfo.LAUNCH_SINGLE_TOP
                            || r.launchMode == ActivityInfo.LAUNCH_SINGLE_TASK) {
                            logStartActivity(EventLogTags.AM_NEW_INTENT, top, top.task);
                            // For paranoia, make sure we have correctly
                            // resumed the top activity.
                            if (doResume) {
                                resumeTopActivityLocked(null);
                            }
                            
                            top.deliverNewIntentLocked(callingUid, r.intent);
                            return START_DELIVERED_TO_TOP;
                        }
                    }
                }
            }

        }

        boolean newTask = false;

        // Should this be considered a new task?
        if (r.resultTo == null && !addingToTask
                && (launchFlags&Intent.FLAG_ACTIVITY_NEW_TASK) != 0) {
            // todo: should do better management of integers.
            mService.mCurTask++;
            if (mService.mCurTask <= 0) {
                mService.mCurTask = 1;
            }
            r.task = new TaskRecord(mService.mCurTask, r.info, intent,
                    (r.info.flags&ActivityInfo.FLAG_CLEAR_TASK_ON_LAUNCH) != 0);
            if (DEBUG_TASKS) Slog.v(TAG, "Starting new activity " + r
                    + " in new task " + r.task);
            newTask = true;
            if (mMainStack) {
                mService.addRecentTaskLocked(r.task);
            }
            
        } else if (sourceRecord != null) {
            
            // An existing activity is starting this new activity, so we want
            // to keep the new one in the same task as the one that is starting
            // it.
            r.task = sourceRecord.task;

        }

        
        startActivityLocked(r, newTask, doResume);
        return START_SUCCESS;
    }

ActivityStack#startActivityLocked

    private final void startActivityLocked(ActivityRecord r, boolean newTask,
            boolean doResume) {
            // newTask = true;  doResume = true;
        final int NH = mHistory.size();

        int addPos = -1;

        // Place a new activity at top of stack, so it is next to interact
        // with the user.
        if (addPos < 0) {
            addPos = NH;
        }
        
        
        // Slot the activity into the history stack and proceed
        mHistory.add(addPos, r);
        r.inHistory = true;
        r.frontOfTask = newTask;
        r.task.numActivities++;
        

        if (doResume) {
            resumeTopActivityLocked(null);
        }
    }

ActivityStack#resumeTopActivityLocked

    final boolean resumeTopActivityLocked(ActivityRecord prev) {
        // prev == null;
        // Find the first activity that is not finishing.
        ActivityRecord next = topRunningActivityLocked(null);

        // Remember how we'll process this pause/resume situation, and ensure
        // that the state is reset however we wind up proceeding.
        final boolean userLeaving = mUserLeaving;
        mUserLeaving = false;

        if (next == null) {
            // There are no more activities!  Let's just start up the
            // Launcher...
            if (mMainStack) {
                return mService.startHomeActivityLocked();
            }
        }

        next.delayedResume = false;
        
        // If the top activity is the resumed one, nothing to do.
        if (mResumedActivity == next && next.state == ActivityState.RESUMED) {
            // Make sure we have executed any pending transitions, since there
            // should be nothing left to do at this point.
            mService.mWindowManager.executeAppTransition();
            mNoAnimActivities.clear();
            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 ((mService.mSleeping || mService.mShuttingDown)
                && mLastPausedActivity == next && next.state == ActivityState.PAUSED) {
            // Make sure we have executed any pending transitions, since there
            // should be nothing left to do at this point.
            mService.mWindowManager.executeAppTransition();
            mNoAnimActivities.clear();
            return false;
        }
        
        // The activity may be waiting for stop, but that is no longer
        // appropriate for it.
        mStoppingActivities.remove(next);
        mWaitingVisibleActivities.remove(next);

        if (DEBUG_SWITCH) Slog.v(TAG, "Resuming " + next);

        // If we are currently pausing an activity, then don't do anything
        // until that is done.
        if (mPausingActivity != null) {
            if (DEBUG_SWITCH) Slog.v(TAG, "Skip resume: pausing=" + mPausingActivity);
            return false;
        }
        
        // We need to start pausing the current activity so the top one
        // can be resumed...
        if (mResumedActivity != null) {
            if (DEBUG_SWITCH) Slog.v(TAG, "Skip resume: need to start pausing");
            startPausingLocked(userLeaving, false);
            return true;
        }

        return true;
    }

ActivityStack#startPausingLocked

    private final void startPausingLocked(boolean userLeaving, boolean uiSleeping) {
    // uiSleeping = false;

        ActivityRecord prev = mResumedActivity;
        
        mResumedActivity = null;
        mPausingActivity = prev;
        mLastPausedActivity = prev;
        prev.state = ActivityState.PAUSING;
        prev.task.touchActiveTime();

        mService.updateCpuStats();
        
        if (prev.app != null && prev.app.thread != null) {
            try {
                
                prev.app.thread.schedulePauseActivity(prev, prev.finishing, userLeaving,
                        prev.configChangeFlags);
                if (mMainStack) {
                    mService.updateUsageStats(prev, false);
                }
            } catch (Exception e) {
                // Ignore exception, if process died other code will cleanup.
                Slog.w(TAG, "Exception thrown during pause", e);
                mPausingActivity = null;
                mLastPausedActivity = null;
            }
        }

        // If we are not going to sleep, we want to ensure the device is
        // awake until the next activity is started.
        if (!mService.mSleeping && !mService.mShuttingDown) {
            mLaunchingActivity.acquire();
            if (!mHandler.hasMessages(LAUNCH_TIMEOUT_MSG)) {
                // To be safe, don't allow the wake lock to be held for too long.
                Message msg = mHandler.obtainMessage(LAUNCH_TIMEOUT_MSG);
                mHandler.sendMessageDelayed(msg, LAUNCH_TIMEOUT);
            }
        }


        if (mPausingActivity != null) {
            // Have the window manager pause its key dispatching until the new
            // activity has started.  If we're pausing the activity just because
            // the screen is being turned off and the UI is sleeping, don't interrupt
            // key dispatch; the same activity will pick it up again on wakeup.
            if (!uiSleeping) {
                prev.pauseKeyDispatchingLocked();
            } else {
                if (DEBUG_PAUSE) Slog.v(TAG, "Key dispatch not paused for screen off");
            }

            // Schedule a pause timeout in case the app doesn't respond.
            // We don't give it much time because this directly impacts the
            // responsiveness seen by the user.
            Message msg = mHandler.obtainMessage(PAUSE_TIMEOUT_MSG);
            msg.obj = prev;
            mHandler.sendMessageDelayed(msg, PAUSE_TIMEOUT);
            if (DEBUG_PAUSE) Slog.v(TAG, "Waiting for pause to complete...");
        }
    }
    

ActivityThread#ApplicationThread#schedulePauseActivity

        public final void schedulePauseActivity(IBinder token, boolean finished,
                boolean userLeaving, int configChanges) {
            queueOrSendMessage(
                    finished ? H.PAUSE_ACTIVITY_FINISHING : H.PAUSE_ACTIVITY,
                    token,
                    (userLeaving ? 1 : 0),
                    configChanges);
        }

                case PAUSE_ACTIVITY:
                    handlePauseActivity((IBinder)msg.obj, false, msg.arg1 != 0, msg.arg2);
                    maybeSnapshot();
                    break;

ActivityThread#handlePauseActivity

    private final void handlePauseActivity(IBinder token, boolean finished,
            boolean userLeaving, int configChanges) {
        ActivityClientRecord r = mActivities.get(token);
        if (r != null) {
            //Slog.v(TAG, "userLeaving=" + userLeaving + " handling pause of " + r);
            if (userLeaving) {
                performUserLeavingActivity(r);
            }

            r.activity.mConfigChangeFlags |= configChanges;
            Bundle state = performPauseActivity(token, finished, true);

            // Make sure any pending writes are now committed.
            QueuedWork.waitToFinish();
            
            // Tell the activity manager we have paused.
            try {
                ActivityManagerNative.getDefault().activityPaused(token, state);
            } catch (RemoteException ex) {
            }
        }
    }

ActivityManagerService#activityPaused

    public final void activityPaused(IBinder token, Bundle icicle) {
        // Refuse possible leaked file descriptors
        if (icicle != null && icicle.hasFileDescriptors()) {
            throw new IllegalArgumentException("File descriptors passed in Bundle");
        }

        final long origId = Binder.clearCallingIdentity();
        mMainStack.activityPaused(token, icicle, false);
        Binder.restoreCallingIdentity(origId);
    }

ActivityStack#activityPaused

    final void activityPaused(IBinder token, Bundle icicle, boolean timeout) {
        if (DEBUG_PAUSE) Slog.v(
            TAG, "Activity paused: token=" + token + ", icicle=" + icicle
            + ", timeout=" + timeout);

        ActivityRecord r = null;

        synchronized (mService) {
            int index = indexOfTokenLocked(token);
            if (index >= 0) {
                r = (ActivityRecord)mHistory.get(index);
                if (!timeout) {
                    r.icicle = icicle;
                    r.haveState = true;
                }
                mHandler.removeMessages(PAUSE_TIMEOUT_MSG, r);
                if (mPausingActivity == r) {
                    r.state = ActivityState.PAUSED;
                    completePauseLocked();
                }
            }
        }
    }

ActivityStack#completePauseLocked

    private final void completePauseLocked() {
        ActivityRecord prev = mPausingActivity;
        
        if (prev != null) {
            
            mPausingActivity = null;
        }

        if (!mService.mSleeping && !mService.mShuttingDown) {
            resumeTopActivityLocked(prev);
        } else {
            
        }
    }

ActivityStack#resumeTopActivityLocked

    final boolean resumeTopActivityLocked(ActivityRecord prev) {
        // Find the first activity that is not finishing.
        ActivityRecord next = topRunningActivityLocked(null);

        // Remember how we'll process this pause/resume situation, and ensure
        // that the state is reset however we wind up proceeding.
        final boolean userLeaving = mUserLeaving;
        mUserLeaving = false;

        if (next == null) {
            // There are no more activities!  Let's just start up the
            // Launcher...
            if (mMainStack) {
                return mService.startHomeActivityLocked();
            }
        }

        next.delayedResume = false;
        
        
        // The activity may be waiting for stop, but that is no longer
        // appropriate for it.
        mStoppingActivities.remove(next);
        mWaitingVisibleActivities.remove(next);


        if (next.app != null && next.app.thread != null) {
            // 应用已启动的情况

        } else {
         // 应用未启动的情况。
            // Whoops, need to restart this activity!
            if (!next.hasBeenLaunched) {
                next.hasBeenLaunched = true;
            } else {
                if (SHOW_APP_STARTING_PREVIEW) {
                    mService.mWindowManager.setAppStartingWindow(
                            next, next.packageName, next.theme,
                            next.nonLocalizedLabel,
                            next.labelRes, next.icon, null, true);
                }
                
            }
            startSpecificActivityLocked(next, true, true);
        }

        return true;
    }

ActivityStack#startSpecificActivityLocked

    private final void startSpecificActivityLocked(ActivityRecord r,
            boolean andResume, boolean checkConfig) {
        // Is this activity's application already running?
        ProcessRecord app = mService.getProcessRecordLocked(r.processName,
                r.info.applicationInfo.uid);
        
        
        if (app != null && app.thread != null) {
            try {
                realStartActivityLocked(r, app, andResume, checkConfig);
                return;
            } catch (RemoteException e) {
                Slog.w(TAG, "Exception when starting activity "
                        + r.intent.getComponent().flattenToShortString(), e);
            }

        }

        mService.startProcessLocked(r.processName, r.info.applicationInfo, true, 0,
                "activity", r.intent.getComponent(), false);
    }

ActivityManagerService#startProcessLocked

    final ProcessRecord startProcessLocked(String processName,
            ApplicationInfo info, boolean knownToBeDead, int intentFlags,
            String hostingType, ComponentName hostingName, boolean allowWhileBooting) {
        ProcessRecord app = getProcessRecordLocked(processName, info.uid);
        
        String hostingNameStr = hostingName != null
                ? hostingName.flattenToShortString() : null;
        
        if (app == null) {
            app = newProcessRecordLocked(null, info, processName);
            mProcessNames.put(processName, info.uid, app);
        } else {
            // If this is a new package in the process, add the package to the list
            app.addPackage(info.packageName);
        }

        startProcessLocked(app, hostingType, hostingNameStr);
        return (app.pid != 0) ? app : null;
    }

ActivityManagerService#startProcessLocked

    private final void startProcessLocked(ProcessRecord app,
            String hostingType, String hostingNameStr) {
        if (app.pid > 0 && app.pid != MY_PID) {
            synchronized (mPidsSelfLocked) {
                mPidsSelfLocked.remove(app.pid);
                mHandler.removeMessages(PROC_START_TIMEOUT_MSG, app);
            }
            app.pid = 0;
        }

        mProcessesOnHold.remove(app);

        updateCpuStats();
        
        System.arraycopy(mProcDeaths, 0, mProcDeaths, 1, mProcDeaths.length-1);
        mProcDeaths[0] = 0;
        
        try {
            int uid = app.info.uid;
            int[] gids = null;
            try {
                gids = mContext.getPackageManager().getPackageGids(
                        app.info.packageName);
            } catch (PackageManager.NameNotFoundException e) {
                Slog.w(TAG, "Unable to retrieve gids", e);
            }
            
            int pid = Process.start("android.app.ActivityThread",
                    mSimpleProcessManagement ? app.processName : null, uid, uid,
                    gids, debugFlags, null);
            
            if (app.persistent) {
                Watchdog.getInstance().processStarted(app.processName, pid);
            }
            
            
            if (pid == 0 || pid == MY_PID) {
                ...
            } else if (pid > 0) {
                app.pid = pid;
                app.removed = false;
                synchronized (mPidsSelfLocked) {
                    this.mPidsSelfLocked.put(pid, app);
                    Message msg = mHandler.obtainMessage(PROC_START_TIMEOUT_MSG);
                    msg.obj = app;
                    mHandler.sendMessageDelayed(msg, PROC_START_TIMEOUT);
                }
            } else {....}
        } catch (RuntimeException e) {....}
    }

ActivityThread#main

    public static final void main(String[] args) {
        SamplingProfilerIntegration.start();

        Process.setArgV0("<pre-initialized>");

        Looper.prepareMainLooper();
        if (sMainThreadHandler == null) {
            sMainThreadHandler = new Handler();
        }

        ActivityThread thread = new ActivityThread();
        thread.attach(false);

        Looper.loop();

        thread.detach();
        String name = (thread.mInitialApplication != null)
            ? thread.mInitialApplication.getPackageName()
            : "<unknown>";
        Slog.i(TAG, "Main thread of " + name + " is now exiting");
    }

    private final void attach(boolean system) {
        sThreadLocal.set(this);
        mSystemThread = system;
        if (!system) {
            
            IActivityManager mgr = ActivityManagerNative.getDefault();
            try {
                mgr.attachApplication(mAppThread);
            } catch (RemoteException ex) {
            }
        }
        
    }

ActivityManagerService#attachApplication

    public final void attachApplication(IApplicationThread thread) {
        synchronized (this) {
            int callingPid = Binder.getCallingPid();
            final long origId = Binder.clearCallingIdentity();
            attachApplicationLocked(thread, callingPid);
            Binder.restoreCallingIdentity(origId);
        }
    }

ActivityManagerService#attachApplicationLocked

    private final boolean attachApplicationLocked(IApplicationThread thread,
            int pid) {

        // Find the application record that is being attached...  either via
        // the pid if we are running in multiple processes, or just pull the
        // next app record if we are emulating process with anonymous threads.
        ProcessRecord app;
        if (pid != MY_PID && pid >= 0) {
            synchronized (mPidsSelfLocked) {
                app = mPidsSelfLocked.get(pid);
            }
        }

        String processName = app.processName;
        try {
            thread.asBinder().linkToDeath(new AppDeathRecipient(
                    app, pid, thread), 0);
        } catch (RemoteException e) {
            
        }
        
        app.thread = thread;
        app.curAdj = app.setAdj = -100;
        app.curSchedGroup = Process.THREAD_GROUP_DEFAULT;
        app.setSchedGroup = Process.THREAD_GROUP_BG_NONINTERACTIVE;
        app.forcingToForeground = null;
        app.foregroundServices = false;
        app.debugging = false;

        mHandler.removeMessages(PROC_START_TIMEOUT_MSG, app);

        boolean normalMode = mProcessesReady || isAllowedWhileBooting(app.info);
        List providers = normalMode ? generateApplicationProvidersLocked(app) : null;
        
        
        try {
            ensurePackageDexOpt(app.instrumentationInfo != null
                    ? app.instrumentationInfo.packageName
                    : app.info.packageName);
            if (app.instrumentationClass != null) {
                ensurePackageDexOpt(app.instrumentationClass.getPackageName());
            }
            // 程序启动的的初始化，Application的创建和生成
            thread.bindApplication(processName, app.instrumentationInfo != null
                    ? app.instrumentationInfo : app.info, providers,
                    app.instrumentationClass, app.instrumentationProfileFile,
                    app.instrumentationArguments, app.instrumentationWatcher, testMode, 
                    isRestrictedBackupMode || !normalMode,
                    mConfiguration, getCommonServicesLocked());
            updateLruProcessLocked(app, false, true);
            app.lastRequestedGc = app.lastLowMemory = SystemClock.uptimeMillis();
        } catch (Exception e) {
            
        }

        boolean badApp = false;
        boolean didSomething = false;

        // See if the top visible activity is waiting to run in this process...
        ActivityRecord hr = mMainStack.topRunningActivityLocked(null);
        if (hr != null && normalMode) {
            if (hr.app == null && app.info.uid == hr.info.applicationInfo.uid
                    && processName.equals(hr.processName)) {
                try {
                    if (mMainStack.realStartActivityLocked(hr, app, true, true)) {
                        didSomething = true;
                    }
                } catch (Exception e) {
                   ...
                }
            } else {
                mMainStack.ensureActivitiesVisibleLocked(hr, null, processName, 0);
            }
        }

        return true;
    }

ActivityStack#realStartActivityLocked

    final boolean realStartActivityLocked(ActivityRecord r,
            ProcessRecord app, boolean andResume, boolean checkConfig)
            throws RemoteException {

        r.startFreezingScreenLocked(app, 0);
        mService.mWindowManager.setAppVisibility(r, true);

        r.app = app;

        int idx = app.activities.indexOf(r);
        if (idx < 0) {
            app.activities.add(r);
        }
        mService.updateLruProcessLocked(app, true, true);

        try {
            
            List<ResultInfo> results = null;
            List<Intent> newIntents = null;
            if (andResume) {
                results = r.results;
                newIntents = r.newIntents;
            }
            
            
            mService.ensurePackageDexOpt(r.intent.getComponent().getPackageName());
            app.thread.scheduleLaunchActivity(new Intent(r.intent), r,
                    System.identityHashCode(r),
                    r.info, r.icicle, results, newIntents, !andResume,
                    mService.isNextTransitionForward());
            
            
        } catch (RemoteException e) {
            
        }

        if (andResume) {
            // As part of the process of launching, ActivityThread also performs
            // a resume.
            r.state = ActivityState.RESUMED;
            r.icicle = null;
            r.haveState = false;
            r.stopped = false;
            mResumedActivity = r;
            r.task.touchActiveTime();
            completeResumeLocked(r);
            pauseIfSleepingLocked();                
        } else {
            
        }
        
        return true;
    }

ApplicationThread#scheduleLaunchActivity

        // we use token to identify this activity without having to send the
        // activity itself back to the activity manager. (matters more with ipc)
        public final void scheduleLaunchActivity(Intent intent, IBinder token, int ident,
                ActivityInfo info, Bundle state, List<ResultInfo> pendingResults,
                List<Intent> pendingNewIntents, boolean notResumed, boolean isForward) {
            ActivityClientRecord r = new ActivityClientRecord();

            r.token = token;
            r.ident = ident;
            r.intent = intent;
            r.activityInfo = info;
            r.state = state;

            r.pendingResults = pendingResults;
            r.pendingIntents = pendingNewIntents;

            r.startsNotResumed = notResumed;
            r.isForward = isForward;

            queueOrSendMessage(H.LAUNCH_ACTIVITY, r);
        }

        case LAUNCH_ACTIVITY: {
            ActivityClientRecord r = (ActivityClientRecord)msg.obj;

            r.packageInfo = getPackageInfoNoCheck(
                  r.activityInfo.applicationInfo);
            handleLaunchActivity(r, null);
        } break;

ActivityThread#handleLaunchActivity

    private final void handleLaunchActivity(ActivityClientRecord r, Intent customIntent) {

        Activity a = performLaunchActivity(r, customIntent);

        if (a != null) {
            r.createdConfig = new Configuration(mConfiguration);
            Bundle oldState = r.state;
            handleResumeActivity(r.token, false, r.isForward);
        }
    }

ActivityThread#performLaunchActivity

    private final Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {
        // System.out.println("##### [" + System.currentTimeMillis() + "] ActivityThread.performLaunchActivity(" + r + ")");

        ActivityInfo aInfo = r.activityInfo;
        if (r.packageInfo == null) {
            r.packageInfo = getPackageInfo(aInfo.applicationInfo,
                    Context.CONTEXT_INCLUDE_CODE);
        }

        ComponentName component = r.intent.getComponent();
        if (component == null) {
            component = r.intent.resolveActivity(
                mInitialApplication.getPackageManager());
            r.intent.setComponent(component);
        }

        if (r.activityInfo.targetActivity != null) {
            component = new ComponentName(r.activityInfo.packageName,
                    r.activityInfo.targetActivity);
        }

        Activity activity = null;
        try {
            java.lang.ClassLoader cl = r.packageInfo.getClassLoader();
            activity = mInstrumentation.newActivity(
                    cl, component.getClassName(), r.intent);
            r.intent.setExtrasClassLoader(cl);
            if (r.state != null) {
                r.state.setClassLoader(cl);
            }
        } catch (Exception e) { ... }

        try {
            Application app = r.packageInfo.makeApplication(false, mInstrumentation);

            if (activity != null) {
                ContextImpl appContext = new ContextImpl();
                appContext.init(r.packageInfo, r.token, this);
                appContext.setOuterContext(activity);
                CharSequence title = r.activityInfo.loadLabel(appContext.getPackageManager());
                Configuration config = new Configuration(mConfiguration);
                
                activity.attach(appContext, this, getInstrumentation(), r.token,
                        r.ident, app, r.intent, r.activityInfo, title, r.parent,
                        r.embeddedID, r.lastNonConfigurationInstance,
                        r.lastNonConfigurationChildInstances, config);

                if (customIntent != null) {
                    activity.mIntent = customIntent;
                }
                r.lastNonConfigurationInstance = null;
                r.lastNonConfigurationChildInstances = null;
                activity.mStartedActivity = false;
                int theme = r.activityInfo.getThemeResource();
                if (theme != 0) {
                    activity.setTheme(theme);
                }

                activity.mCalled = false;
                mInstrumentation.callActivityOnCreate(activity, r.state);
                
                r.activity = activity;
                r.stopped = true;
                
            }
            r.paused = true;

            mActivities.put(r.token, r);

        } catch (SuperNotCalledException e) {
            ...
        } catch (Exception e) {
            ...
        }

        return activity;
    }

ActivityThread# handleResumeActivity

    final void handleResumeActivity(IBinder token, boolean clearHide, boolean isForward) {
        

        ActivityClientRecord r = performResumeActivity(token, clearHide);

        if (r != null) {
            final Activity a = r.activity;

            final int forwardBit = isForward ?
                    WindowManager.LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION : 0;

            // If the window hasn't yet been added to the window manager,
            // and this guy didn't finish itself or start another activity,
            // then go ahead and add the window.
            boolean willBeVisible = !a.mStartedActivity;
            if (!willBeVisible) {
                try {
                    willBeVisible = ActivityManagerNative.getDefault().willActivityBeVisible(
                            a.getActivityToken());
                } catch (RemoteException e) {
                }
            }
            if (r.window == null && !a.mFinished && willBeVisible) {
                r.window = r.activity.getWindow();
                View decor = r.window.getDecorView();
                decor.setVisibility(View.INVISIBLE);
                ViewManager wm = a.getWindowManager();
                WindowManager.LayoutParams l = r.window.getAttributes();
                a.mDecor = decor;
                l.type = WindowManager.LayoutParams.TYPE_BASE_APPLICATION;
                l.softInputMode |= forwardBit;
                if (a.mVisibleFromClient) {
                    a.mWindowAdded = true;
                    wm.addView(decor, l);
                }

            // If the window has already been added, but during resume
            // we started another activity, then don't yet make the
            // window visible.
            } else if (!willBeVisible) {
                if (localLOGV) Slog.v(
                    TAG, "Launch " + r + " mStartedActivity set");
                r.hideForNow = true;
            }

            // The window is now visible if it has been added, we are not
            // simply finishing, and we are not starting another activity.
            if (!r.activity.mFinished && willBeVisible
                    && r.activity.mDecor != null && !r.hideForNow) {
                if (r.newConfig != null) {
                    if (DEBUG_CONFIGURATION) Slog.v(TAG, "Resuming activity "
                            + r.activityInfo.name + " with newConfig " + r.newConfig);
                    performConfigurationChanged(r.activity, r.newConfig);
                    r.newConfig = null;
                }
                if (localLOGV) Slog.v(TAG, "Resuming " + r + " with isForward="
                        + isForward);
                WindowManager.LayoutParams l = r.window.getAttributes();
                if ((l.softInputMode
                        & WindowManager.LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION)
                        != forwardBit) {
                    l.softInputMode = (l.softInputMode
                            & (~WindowManager.LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION))
                            | forwardBit;
                    if (r.activity.mVisibleFromClient) {
                        ViewManager wm = a.getWindowManager();
                        View decor = r.window.getDecorView();
                        wm.updateViewLayout(decor, l);
                    }
                }
                r.activity.mVisibleFromServer = true;
                mNumVisibleActivities++;
                if (r.activity.mVisibleFromClient) {
                    r.activity.makeVisible();
                }
            }

            r.nextIdle = mNewActivities;
            mNewActivities = r;
            if (localLOGV) Slog.v(
                TAG, "Scheduling idle handler for " + r);
            Looper.myQueue().addIdleHandler(new Idler());

        } else {
            // If an exception was thrown when trying to resume, then
            // just end this activity.
            try {
                ActivityManagerNative.getDefault()
                    .finishActivity(token, Activity.RESULT_CANCELED, null);
            } catch (RemoteException ex) {
            }
        }
    }