Launcher启动过程

private void startOtherServices(@NonNull TimingsTraceAndSlog t) {
    ...
    // We now tell the activity manager it is okay to run third party
    // code.  It will call back into us once it has gotten to the state
    // where third party code can really run (but before it has actually
    // started launching the initial applications), for us to complete our
    // initialization.
    //启动Launcher入口
    mActivityManagerService.systemReady(() -> {
            Slog.i(TAG, "Making services ready");
            t.traceBegin("StartActivityManagerReadyPhase");
            mSystemServiceManager.startBootPhase(t, SystemService.PHASE_ACTIVITY_MANAGER_READY);
    ...
}

public ActivityManagerService(Context systemContext, ActivityTaskManagerService atm) {
     ...
     mAtmInternal = LocalServices.getService(ActivityTaskManagerInternal.class);
 }
public void systemReady(final Runnable goingCallback, @NonNull TimingsTraceAndSlog t) {
    synchronized(this) {
            if (mSystemReady) {
                // If we're done calling all the receivers, run the next "boot phase" passed in
                // by the SystemServer
                if (goingCallback != null) {
                    goingCallback.run();
                }
                t.traceEnd(); // PhaseActivityManagerReady
                return;
            }
    ...
    if (bootingSystemUser) {
                t.traceBegin("startHomeOnAllDisplays");
                mAtmInternal.startHomeOnAllDisplays(currentUserId, "systemReady");
                t.traceEnd();
    }
    ...
}

private void start() {
    //添加ActivityTaskManagerInternal
    LocalServices.addService(ActivityTaskManagerInternal.class, mInternal);
}
@Override
public boolean startHomeOnAllDisplays(int userId, String reason) {
    synchronized (mGlobalLock) {
        return mRootWindowContainer.startHomeOnAllDisplays(userId, reason);
    }
}

boolean startHomeOnAllDisplays(int userId, String reason) {
        boolean homeStarted = false;
        for (int i = getChildCount() - 1; i >= 0; i--) {
            final int displayId = getChildAt(i).mDisplayId;
            homeStarted |= startHomeOnDisplay(userId, reason, displayId);
        }
        return homeStarted;
    }
boolean startHomeOnDisplay(int userId, String reason, int displayId) {
        return startHomeOnDisplay(userId, reason, displayId, false /* allowInstrumenting */,
                false /* fromHomeKey */);
    }

boolean startHomeOnDisplay(int userId, String reason, int displayId, boolean allowInstrumenting,
            boolean fromHomeKey) {
        // Fallback to top focused display or default display if the displayId is invalid.
        if (displayId == INVALID_DISPLAY) {
            final Task rootTask = getTopDisplayFocusedRootTask();
            displayId = rootTask != null ? rootTask.getDisplayId() : DEFAULT_DISPLAY;
        }

        final DisplayContent display = getDisplayContent(displayId);
        return display.reduceOnAllTaskDisplayAreas((taskDisplayArea, result) ->
                        result | startHomeOnTaskDisplayArea(userId, reason, taskDisplayArea,
                                allowInstrumenting, fromHomeKey),
                false /* initValue */);
    }
boolean startHomeOnTaskDisplayArea(int userId, String reason, TaskDisplayArea taskDisplayArea,
            boolean allowInstrumenting, boolean fromHomeKey) {
    if (taskDisplayArea == getDefaultTaskDisplayArea()) {
        	//获取启动信息
            homeIntent = mService.getHomeIntent();
            aInfo = resolveHomeActivity(userId, homeIntent);
        } else if (shouldPlaceSecondaryHomeOnDisplayArea(taskDisplayArea)) {
            Pair<ActivityInfo, Intent> info = resolveSecondaryHomeActivity(userId, taskDisplayArea);
            aInfo = info.first;
            homeIntent = info.second;
        }
        if (aInfo == null || homeIntent == null) {
            return false;
        }

        if (!canStartHomeOnDisplayArea(aInfo, taskDisplayArea, allowInstrumenting)) {
            return false;
        }
    final String myReason = reason + ":" + userId + ":" + UserHandle.getUserId(
                aInfo.applicationInfo.uid) + ":" + taskDisplayArea.getDisplayId();
    //启动Launcher
    mService.getActivityStartController().startHomeActivity(homeIntent, aInfo, myReason,
                taskDisplayArea);
}

String mTopAction = Intent.ACTION_MAIN;
Intent getHomeIntent() {
        Intent intent = new Intent(mTopAction, mTopData != null ? Uri.parse(mTopData) : null);
        intent.setComponent(mTopComponent);
        intent.addFlags(Intent.FLAG_DEBUG_TRIAGED_MISSING);
    	//FACTORY_TEST_LOW_LEVEL 低级工厂模式
        if (mFactoryTest != FactoryTest.FACTORY_TEST_LOW_LEVEL) {
            intent.addCategory(Intent.CATEGORY_HOME);
        }
        return intent;
}
ActivityStartController getActivityStartController() {
    return mActivityStartController;
}

void startHomeActivity(Intent intent, ActivityInfo aInfo, String reason,
            TaskDisplayArea taskDisplayArea) {
    ...
    if (rootHomeTask.mInResumeTopActivity) {
            // If we are in resume section already, home activity will be initialized, but not
            // resumed (to avoid recursive resume) and will stay that way until something pokes it
            // again. We need to schedule another resume.
            mSupervisor.scheduleResumeTopActivities();
        }
}

<manifest
    xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.android.launcher3">
    <uses-sdk android:targetSdkVersion="33" android:minSdkVersion="26"/>
    <!--
    Manifest entries specific to Launcher3. This is merged with AndroidManifest-common.xml.
    Refer comments around specific entries on how to extend individual components.
    -->

    <application
        android:backupAgent="com.android.launcher3.LauncherBackupAgent"
        android:fullBackupOnly="true"
        android:fullBackupContent="@xml/backupscheme"
        android:hardwareAccelerated="true"
        android:debuggable="true"
        android:icon="@drawable/ic_launcher_home"
        android:label="@string/derived_app_name"
        android:theme="@style/AppTheme"
        android:largeHeap="@bool/config_largeHeap"
        android:restoreAnyVersion="true"
        android:supportsRtl="true" >

        <!--
        Main launcher activity. When extending only change the name, and keep all the
        attributes and intent filters the same
        -->
        <activity
            android:name="com.android.launcher3.Launcher"
            android:launchMode="singleTask"
            android:clearTaskOnLaunch="true"
            android:stateNotNeeded="true"
            android:windowSoftInputMode="adjustPan"
            android:screenOrientation="unspecified"
            android:configChanges="keyboard|keyboardHidden|mcc|mnc|navigation|orientation|screenSize|screenLayout|smallestScreenSize"
            android:resizeableActivity="true"
            android:resumeWhilePausing="true"
            android:taskAffinity=""
            android:exported="true"
            android:enabled="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <action android:name="android.intent.action.SHOW_WORK_APPS" />
                <category android:name="android.intent.category.HOME" />
                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.MONKEY"/>
                <category android:name="android.intent.category.LAUNCHER_APP" />
            </intent-filter>
            <meta-data
                android:name="com.android.launcher3.grid.control"
                android:value="${packageName}.grid_control" />
        </activity>

    </application>
</manifest>

import com.android.launcher3.model.BgDataModel.Callbacks;
public class Launcher extends StatefulActivity<LauncherState>
        implements LauncherExterns, Callbacks, InvariantDeviceProfile.OnIDPChangeListener,
        PluginListener<LauncherOverlayPlugin>, LauncherOverlayCallbacks {
            
    private LauncherModel Model; 
            
	@Override
	@TargetApi(Build.VERSION_CODES.S)
	protected void onCreate(Bundle savedInstanceState) {
     	 ...
    	 LauncherAppState app = LauncherAppState.getInstance(this);
    	 mOldConfig = new Configuration(getResources().getConfiguration());
    	 mModel = app.getModel();
   	  ...
   	  if (!mModel.addCallbacksAndLoad(this)) {
            if (!internalStateHandled) {
                Log.d(BAD_STATE, "Launcher onCreate not binding sync, prevent drawing");
                // If we are not binding synchronously, pause drawing until initial bind complete,
                // so that the system could continue to show the device loading prompt
                mOnInitialBindListener = Boolean.FALSE::booleanValue;
            }
        }
	}
}

import static com.android.launcher3.util.Executors.MODEL_EXECUTOR;

public boolean addCallbacksAndLoad(Callbacks callbacks) {
        synchronized (mLock) {
            addCallbacks(callbacks);
            return startLoader(new Callbacks[] { callbacks });
        }
}
public void addCallbacks(Callbacks callbacks) {
            mCallbacksList.add(callbacks)
}
public Callbacks[] getCallbacks() {
        return mCallbacksList.toArray(new Callbacks[mCallbacksList.size()]);
}
private boolean startLoader(Callbacks[] newCallbacks) {
    	   ...
           // If there is already one running, tell it to stop.
           boolean wasRunning = stopLoader();
		   final Callbacks[] callbacksList = bindAllCallbacks ? getCallbacks() : newCallbacks;
           LoaderResults loaderResults = new LoaderResults(
                        mApp, mBgDataModel, mBgAllAppsList, callbacksList);
           if (bindDirectly) {
                 // Divide the set of loaded items into those that we are binding synchronously,
                 // and everything else that is to be bound normally (asynchronously).
                 loaderResults.bindWorkspace(bindAllCallbacks);
                 // For now, continue posting the binding of AllApps as there are other
                 // issues that arise from that.
                 loaderResults.bindAllApps();
                 loaderResults.bindDeepShortcuts();
                 loaderResults.bindWidgets();
                 return true;
             } else {
                 stopLoader();
                 mLoaderTask = new LoaderTask(
                         mApp, mBgAllAppsList, mBgDataModel, mModelDelegate, loaderResults);
                 // Always post the loader task, instead of running directly
                 // (even on same thread) so that we exit any nested synchronized blocks
                 MODEL_EXECUTOR.post(mLoaderTask);
             }    
}
private boolean stopLoader() {
        synchronized (mLock) {
            LoaderTask oldTask = mLoaderTask;
            mLoaderTask = null;
            if (oldTask != null) {
                oldTask.stopLocked();
                return true;
            }
            return false;
        }
    }
 public LoaderTransaction beginLoader(LoaderTask task) throws CancellationException {
        return new LoaderTransaction(task);
    }
public class LoaderTransaction implements AutoCloseable {
        private final LoaderTask mTask;
        private LoaderTransaction(LoaderTask task) throws CancellationException {
            synchronized (mLock) {
                mTask = task;
                mIsLoaderTaskRunning = true;
                mModelLoaded = false;
            }
        }
        public void commit() {
            synchronized (mLock) {
                // Everything loaded bind the data.
                mModelLoaded = true;
            }
        }
    }

public class LoaderTask implements Runnable {
    private final LoaderResults mResults;
	public LoaderTask(LauncherAppState app, AllAppsList bgAllAppsList, BgDataModel dataModel,
            ModelDelegate modelDelegate, LoaderResults results) {
        mApp = app;
        mBgAllAppsList = bgAllAppsList;
        mBgDataModel = dataModel;
        mModelDelegate = modelDelegate;
        mResults = results;

        mLauncherApps = mApp.getContext().getSystemService(LauncherApps.class);
        mUserManager = mApp.getContext().getSystemService(UserManager.class);
        mUserCache = UserCache.INSTANCE.get(mApp.getContext());
        mSessionHelper = InstallSessionHelper.INSTANCE.get(mApp.getContext());
        mIconCache = mApp.getIconCache();
	}
	public void run() {
	 try (LauncherModel.LoaderTransaction transaction = mApp.getModel().beginLoader(this)) {
    	 try {
             //加载工作区信息
              loadWorkspace(allShortcuts, memoryLogger);
         } finally {
               Trace.endSection();
      	}
         //绑定工作区信息
         mResults.bindWorkspace(true /* incrementBindId */);
		 // Notify the installer packages of packages with active installs on the first screen.
         sendFirstScreenActiveInstallsBroadcast();
    	 try {
             //加载系统已经安装的应用程序信息
          	allActivityList = loadAllApps();
         } finally {
             Trace.endSection();
         }
         mResults.bindAllApps();
         mResults.bindDeepShortcuts();
         mResults.bindWidgets();
         transaction.commit();
    }
} 

public BaseLoaderResults(LauncherAppState app, BgDataModel dataModel,
            AllAppsList allAppsList, Callbacks[] callbacksList, LooperExecutor uiExecutor) {
        mUiExecutor = uiExecutor;
        mApp = app;
        mBgDataModel = dataModel;
        mBgAllAppsList = allAppsList;
        mCallbacksList = callbacksList;
    }
public void bindAllApps() {
        // shallow copy
        AppInfo[] apps = mBgAllAppsList.copyData();
        int flags = mBgAllAppsList.getFlags();
        executeCallbacksTask(c -> c.bindAllApplications(apps, flags), mUiExecutor);
    }
protected void executeCallbacksTask(CallbackTask task, Executor executor) {
        executor.execute(() -> {
            if (mMyBindingId != mBgDataModel.lastBindId) {
                Log.d(TAG, "Too many consecutive reloads, skipping obsolete data-bind");
                return;
            }
            for (Callbacks cb : mCallbacksList) {
                task.execute(cb);
            }
        });
    }

ActivityAllAppsContainerView<Launcher> mAppsView;

@Override
    @TargetApi(Build.VERSION_CODES.S)
        public void bindAllApplications(AppInfo[] apps, int flags) {
        mAppsView.getAppsStore().setApps(apps, flags);
        PopupContainerWithArrow.dismissInvalidPopup(this);
        if (Utilities.ATLEAST_S) {
            Trace.endAsyncSection(DISPLAY_ALL_APPS_TRACE_METHOD_NAME,
                    DISPLAY_ALL_APPS_TRACE_COOKIE);
        }
    }

public AllAppsStore getAppsStore() {
        return mAllAppsStore;
}
private void onAppsUpdated() {
        mHasWorkApps = Stream.of(mAllAppsStore.getApps()).anyMatch(mWorkManager.getMatcher());
        if (!isSearching()) {
            rebindAdapters();
            if (mHasWorkApps) {
                mWorkManager.reset();
            }
        }
    }

public void setApps(AppInfo[] apps, int flags) {
        mApps = apps;
        mModelFlags = flags;
        notifyUpdate();
    }
private void notifyUpdate() {
        if (mDeferUpdatesFlags != 0) {
            mUpdatePending = true;
            return;
        }
        for (OnUpdateListener listener : mUpdateListeners) {
            listener.onAppsUpdated();
        }
    }

protected BaseAllAppsContainerView(Context context, AttributeSet attrs, int defStyleAttr) {
     mAllAppsStore.addUpdateListener(this::onAppsUpdated);
}
	@Override
    protected void rebindAdapters(boolean force) {
        super.rebindAdapters(force);
        if (!FeatureFlags.ENABLE_DEVICE_SEARCH.get()
                || getMainAdapterProvider().getDecorator() == null) {
            return;
        }

        RecyclerView.ItemDecoration decoration = getMainAdapterProvider().getDecorator();
        mAH.stream()
                .map(adapterHolder -> adapterHolder.mRecyclerView)
                .filter(Objects::nonNull)
                .forEach(v -> {
                    v.removeItemDecoration(decoration); // Remove in case it is already added.
                    v.addItemDecoration(decoration);
                });
    }
//packages/apps/Launcher3/src/com/android/launcher3/allapps/BaseAllAppsContainerView.java
 public class AdapterHolder {
        public static final int MAIN = 0;
        public static final int WORK = 1;
        public static final int SEARCH = 2;

        private final int mType;
        public final BaseAllAppsAdapter<T> mAdapter;
        final RecyclerView.LayoutManager mLayoutManager;
        final AlphabeticalAppsList<T> mAppsList;
        final Rect mPadding = new Rect();
        AllAppsRecyclerView mRecyclerView;

        AdapterHolder(int type) {
            mType = type;
            mAppsList = new AlphabeticalAppsList<>(mActivityContext,
                    isSearch() ? null : mAllAppsStore,
                    isWork() ? mWorkManager.getAdapterProvider() : null);

            BaseAdapterProvider[] adapterProviders =
                    isWork() ? new BaseAdapterProvider[]{mMainAdapterProvider,
                            mWorkManager.getAdapterProvider()}
                            : new BaseAdapterProvider[]{mMainAdapterProvider};

            mAdapter = createAdapter(mAppsList, adapterProviders);
            mAppsList.setAdapter(mAdapter);
            mLayoutManager = mAdapter.getLayoutManager();
        }
	@Override
    protected BaseAllAppsAdapter<T> createAdapter(AlphabeticalAppsList<T> appsList,
            BaseAdapterProvider[] adapterProviders) {
        return new AllAppsGridAdapter<>(mActivityContext, getLayoutInflater(), appsList,
                adapterProviders);
    }

public BaseAllAppsAdapter(T activityContext, LayoutInflater inflater,
            AlphabeticalAppsList<T> apps, BaseAdapterProvider[] adapterProviders) {
        Resources res = activityContext.getResources();
        mActivityContext = activityContext;
        mApps = apps;
        mEmptySearchMessage = res.getString(R.string.all_apps_loading_message);
        mLayoutInflater = inflater;

        mOnIconClickListener = mActivityContext.getItemOnClickListener();

        mAdapterProviders = adapterProviders;
        mExtraHeight = res.getDimensionPixelSize(R.dimen.all_apps_height_extra);
    }	
	@Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        switch (viewType) {
            case VIEW_TYPE_ICON:
                int layout = !FeatureFlags.ENABLE_TWOLINE_ALLAPPS.get() ? R.layout.all_apps_icon
                        : R.layout.all_apps_icon_twoline;
                BubbleTextView icon = (BubbleTextView) mLayoutInflater.inflate(
                        layout, parent, false);
                icon.setLongPressTimeoutFactor(1f);
                icon.setOnFocusChangeListener(mIconFocusListener);
                icon.setOnClickListener(mOnIconClickListener);
                icon.setOnLongClickListener(mOnIconLongClickListener);
                // Ensure the all apps icon height matches the workspace icons in portrait mode.
                icon.getLayoutParams().height =
                        mActivityContext.getDeviceProfile().allAppsCellHeightPx;
                if (FeatureFlags.ENABLE_TWOLINE_ALLAPPS.get()) {
                    icon.getLayoutParams().height += mExtraHeight;
                }
                return new ViewHolder(icon);
            case VIEW_TYPE_EMPTY_SEARCH:
                return new ViewHolder(mLayoutInflater.inflate(R.layout.all_apps_empty_search,
                        parent, false));
            case VIEW_TYPE_SEARCH_MARKET:
                View searchMarketView = mLayoutInflater.inflate(R.layout.all_apps_search_market,
                        parent, false);
                searchMarketView.setOnClickListener(mMarketSearchClickListener);
                return new ViewHolder(searchMarketView);
            case VIEW_TYPE_ALL_APPS_DIVIDER:
                return new ViewHolder(mLayoutInflater.inflate(
                        R.layout.all_apps_divider, parent, false));
            default:
                BaseAdapterProvider adapterProvider = getAdapterProvider(viewType);
                if (adapterProvider != null) {
                    return adapterProvider.onCreateViewHolder(mLayoutInflater, parent, viewType);
                }
                throw new RuntimeException("Unexpected view type" + viewType);
        }
    }
	@Override
    public int getItemViewType(int position) {
        AdapterItem item = mApps.getAdapterItems().get(position);
        return item.viewType;
    }

	@Override
    public View.OnClickListener getItemOnClickListener() {
        return ItemClickHandler.INSTANCE;
    }

public static final OnClickListener INSTANCE = ItemClickHandler::onClick;

    private static void onClick(View v) {
        // Make sure that rogue clicks don't get through while allapps is launching, or after the
        // view has detached (it's possible for this to happen if the view is removed mid touch).
        if (v.getWindowToken() == null) return;

        Launcher launcher = Launcher.getLauncher(v.getContext());
        if (!launcher.getWorkspace().isFinishedSwitchingState()) return;

        Object tag = v.getTag();
        //tag instance 为AppInfo
        if (tag instanceof WorkspaceItemInfo) {
            onClickAppShortcut(v, (WorkspaceItemInfo) tag, launcher);
        } else if (tag instanceof FolderInfo) {
            if (v instanceof FolderIcon) {
                onClickFolderIcon(v);
            }
        } else if (tag instanceof AppInfo) {
            startAppShortcutOrInfoActivity(v, (AppInfo) tag, launcher);
        } else if (tag instanceof LauncherAppWidgetInfo) {
            if (v instanceof PendingAppWidgetHostView) {
                onClickPendingWidget((PendingAppWidgetHostView) v, launcher);
            }
        } else if (tag instanceof SearchActionItemInfo) {
            onClickSearchAction(launcher, (SearchActionItemInfo) tag);
        }
    }
private static void startAppShortcutOrInfoActivity(View v, ItemInfo item, Launcher launcher) {
        TestLogging.recordEvent(
                TestProtocol.SEQUENCE_MAIN, "start: startAppShortcutOrInfoActivity");
        Intent intent;
        if (item instanceof ItemInfoWithIcon
                && (((ItemInfoWithIcon) item).runtimeStatusFlags
                & ItemInfoWithIcon.FLAG_INSTALL_SESSION_ACTIVE) != 0) {
            ItemInfoWithIcon appInfo = (ItemInfoWithIcon) item;
            intent = new PackageManagerHelper(launcher)
                    .getMarketIntent(appInfo.getTargetComponent().getPackageName());
        } else {
            intent = item.getIntent();
        }
        if (intent == null) {
            throw new IllegalArgumentException("Input must have a valid intent");
        }
        if (item instanceof WorkspaceItemInfo) {
            WorkspaceItemInfo si = (WorkspaceItemInfo) item;
            if (si.hasStatusFlag(WorkspaceItemInfo.FLAG_SUPPORTS_WEB_UI)
                    && Intent.ACTION_VIEW.equals(intent.getAction())) {
                // make a copy of the intent that has the package set to null
                // we do this because the platform sometimes disables instant
                // apps temporarily (triggered by the user) and fallbacks to the
                // web ui. This only works though if the package isn't set
                intent = new Intent(intent);
                intent.setPackage(null);
            }
            if ((si.options & WorkspaceItemInfo.FLAG_START_FOR_RESULT) != 0) {
                launcher.startActivityForResult(item.getIntent(), 0);
                InstanceId instanceId = new InstanceIdSequence().newInstanceId();
                launcher.logAppLaunch(launcher.getStatsLogManager(), item, instanceId);
                return;
            }
        }
        if (v != null && launcher.supportsAdaptiveIconAnimation(v)) {
            // Preload the icon to reduce latency b/w swapping the floating view with the original.
            FloatingIconView.fetchIcon(launcher, v, item, true /* isOpening */);
        }
    	//启动应用程序
        launcher.startActivitySafely(v, intent, item);
    }

public class Launcher extends StatefulActivity<LauncherState>
        implements LauncherExterns, Callbacks, InvariantDeviceProfile.OnIDPChangeListener,
        PluginListener<LauncherOverlayPlugin>, LauncherOverlayCallbacks {
            
	@Override
    public boolean startActivitySafely(View v, Intent intent, ItemInfo item) {
        if (!hasBeenResumed()) {
            // Workaround an issue where the WM launch animation is clobbered when finishing the
            // recents animation into launcher. Defer launching the activity until Launcher is
            // next resumed.
            addOnResumeCallback(() -> startActivitySafely(v, intent, item));
            if (mOnDeferredActivityLaunchCallback != null) {
                mOnDeferredActivityLaunchCallback.run();
                mOnDeferredActivityLaunchCallback = null;
            }
            return true;
        }

        boolean success = super.startActivitySafely(v, intent, item);
        if (success && v instanceof BubbleTextView) {
            // This is set to the view that launched the activity that navigated the user away
            // from launcher. Since there is no callback for when the activity has finished
            // launching, enable the press state and keep this reference to reset the press
            // state when we return to launcher.
            BubbleTextView btv = (BubbleTextView) v;
            btv.setStayPressed(true);
            addOnResumeCallback(() -> btv.setStayPressed(false));
        }
        return success;
    }        
}

default boolean startActivitySafely( View v, Intent intent, @Nullable ItemInfo item) {
        Context context = (Context) this;
        if (isAppBlockedForSafeMode() && !PackageManagerHelper.isSystemApp(context, intent)) {
            Toast.makeText(context, R.string.safemode_shortcut_error, Toast.LENGTH_SHORT).show();
            return false;
        }
        Bundle optsBundle = (v != null) ? getActivityLaunchOptions(v, item).toBundle() : null;
        UserHandle user = item == null ? null : item.user;
        // Prepare intent
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        if (v != null) {
            intent.setSourceBounds(Utilities.getViewBounds(v));
        }
        try {
            boolean isShortcut = (item instanceof WorkspaceItemInfo)
                    && (item.itemType == LauncherSettings.Favorites.ITEM_TYPE_SHORTCUT
                    || item.itemType == LauncherSettings.Favorites.ITEM_TYPE_DEEP_SHORTCUT)
                    && !((WorkspaceItemInfo) item).isPromise();
            if (isShortcut) {
                // Shortcuts need some special checks due to legacy reasons.
                startShortcutIntentSafely(intent, optsBundle, item);
            } else if (user == null || user.equals(Process.myUserHandle())) {
                // Could be launching some bookkeeping activity
                //启动应用程序
                context.startActivity(intent, optsBundle);
            } else {
                context.getSystemService(LauncherApps.class).startMainActivity(
                        intent.getComponent(), user, intent.getSourceBounds(), optsBundle);
            }
            if (item != null) {
                InstanceId instanceId = new InstanceIdSequence().newInstanceId();
                logAppLaunch(getStatsLogManager(), item, instanceId);
            }
            return true;
        } catch (NullPointerException | ActivityNotFoundException | SecurityException e) {
            Toast.makeText(context, R.string.activity_not_found, Toast.LENGTH_SHORT).show();
            Log.e(TAG, "Unable to launch. tag=" + item + " intent=" + intent, e);
        }
        return false;
    }