Launcher3学习记录-Launcher第一次启动时的快捷方式、Widget加载流程

 

Launcher3的主Activity是Launcher.java，在onCreate()方法中可以找到数据下载的入口。mModel 是类LauncherModel的引用。

        if (!mModel.startLoader(mWorkspace.getRestorePage())) {
            // If we are not binding synchronously, show a fade in animation when
            // the first page bind completes.
            mDragLayer.setAlpha(0);
        } else {
            setWorkspaceLoading(true);
        }

在startLoader方法中可以看到，启动了一个名为LoaderTask的子线程。

    public boolean startLoader(int synchronousBindPage) {
        // Enable queue before starting loader. It will get disabled in Launcher#finishBindingItems
        InstallShortcutReceiver.enableInstallQueue();
        synchronized (mLock) {
            // Don't bother to start the thread if we know it's not going to do anything
            if (mCallbacks != null && mCallbacks.get() != null) {
                final Callbacks oldCallbacks = mCallbacks.get();
                // Clear any pending bind-runnables from the synchronized load process.
                runOnMainThread(new Runnable() {
                    public void run() {
                        oldCallbacks.clearPendingBinds();
                    }
                });

                // If there is already one running, tell it to stop.
                stopLoaderLocked();
                mLoaderTask = new LoaderTask(mApp.getContext(), synchronousBindPage);
                // TODO: mDeepShortcutsLoaded does not need to be true for synchronous bind.
                if (synchronousBindPage != PagedView.INVALID_RESTORE_PAGE && mAllAppsLoaded
                        && mWorkspaceLoaded && mDeepShortcutsLoaded && !mIsLoaderTaskRunning) {
                    mLoaderTask.runBindSynchronousPage(synchronousBindPage);
                    return true;
                } else {
                    sWorkerThread.setPriority(Thread.NORM_PRIORITY);
                    sWorker.post(mLoaderTask);
                }
            }
        }
        return false;
    }

可以看到，LoaderTask 类 实现了Runnable接口，run()方法中明确了加载的三步骤：1、loadAndBindWorkspace()  加载桌面，包括加载桌面上的应用、widget、快捷方式等图标；2、loadAndBindAllApps() 加载AllApps 界面；3、loadAndBindDeepShortcuts() 加载 deep shortcuts ，这个是7.1的ROM上才会有的功能。

    private class LoaderTask implements Runnable {
        public void run() {
            synchronized (mLock) {
                if (mStopped) {
                    return;
                }
                mIsLoaderTaskRunning = true;
            }
            // Optimize for end-user experience: if the Launcher is up and // running with the
            // All Apps interface in the foreground, load All Apps first. Otherwise, load the
            // workspace first (default).
            keep_running: {
                if (DEBUG_LOADERS) Log.d(TAG, "step 1: loading workspace");
                loadAndBindWorkspace();

                if (mStopped) {
                    break keep_running;
                }

                waitForIdle();

                // second step
                if (DEBUG_LOADERS) Log.d(TAG, "step 2: loading all apps");
                loadAndBindAllApps();

                waitForIdle();

                // third step
                if (DEBUG_LOADERS) Log.d(TAG, "step 3: loading deep shortcuts");
                loadAndBindDeepShortcuts();
            }

            // Clear out this reference, otherwise we end up holding it until all of the
            // callback runnables are done.
            mContext = null;

            synchronized (mLock) {
                // If we are still the last one to be scheduled, remove ourselves.
                if (mLoaderTask == this) {
                    mLoaderTask = null;
                }
                mIsLoaderTaskRunning = false;
                mHasLoaderCompletedOnce = true;
            }
        }
    }

接下来看下loadAndBindWorkspace() 方法，其中loadWorkspace()方法 加载数据，bindWorkspace()方法 将快捷方式和widget显示到界面上。

        private void loadAndBindWorkspace() {
            mIsLoadingAndBindingWorkspace = true;

            // Load the workspace
            if (DEBUG_LOADERS) {
                Log.d(TAG, "loadAndBindWorkspace mWorkspaceLoaded=" + mWorkspaceLoaded);
            }

            if (!mWorkspaceLoaded) {
                loadWorkspace();
                synchronized (LoaderTask.this) {
                    if (mStopped) {
                        return;
                    }
                    mWorkspaceLoaded = true;
                }
            }

            // Bind the workspace
            bindWorkspace(mPageToBindFirst);
        }

loadWorkspace()方法就比较复杂了，但是大致分为几部：1、加载launcher的默认布局；2、查询并遍历数据库，将数据缓存起来，同时将异常数据添加到待删除数组中，比如被禁用的应用、已卸载的应用 等异常数据；3、删除异常数据，异常的图标、异常的文件夹、异常的页面；4、重新整理剩下的数据。

        private void loadWorkspace() {
            ...
            Log.d(TAG, "loadWorkspace: loading default favorites");
            LauncherSettings.Settings.call(contentResolver, LauncherSettings.Settings.METHOD_LOAD_DEFAULT_FAVORITES);
            
                sBgWorkspaceScreens.addAll(loadWorkspaceScreensDb(mContext));//加载页面顺序
                
                final Uri contentUri = LauncherSettings.Favorites.CONTENT_URI;
                if (DEBUG_LOADERS) Log.d(TAG, "loading model from " + contentUri);
                final Cursor c = contentResolver.query(contentUri, null, null, null, null);
                while (!mStopped && c.moveToNext()) {
                    int itemType = c.getInt(itemTypeIndex);
                    container = c.getInt(containerIndex);
                    switch (itemType) {
                    case LauncherSettings.Favorites.ITEM_TYPE_APPLICATION:
                    case LauncherSettings.Favorites.ITEM_TYPE_SHORTCUT:
                    case LauncherSettings.Favorites.ITEM_TYPE_DEEP_SHORTCUT:
                    ...
                    sBgWorkspaceItems.add(info);
                    sBgItemsIdMap.put(info.id, info);
                    break;
                    case LauncherSettings.Favorites.ITEM_TYPE_FOLDER:
                    ...
                    sBgWorkspaceItems.add(folderInfo);
                    sBgItemsIdMap.put(folderInfo.id, folderInfo);
                    sBgFolders.put(folderInfo.id, folderInfo);
                    break;
                    case LauncherSettings.Favorites.ITEM_TYPE_APPWIDGET:
                    case LauncherSettings.Favorites.ITEM_TYPE_CUSTOM_APPWIDGET:
                    sBgItemsIdMap.put(appWidgetInfo.id, appWidgetInfo);
                    sBgAppWidgets.add(appWidgetInfo);
                    break;
                    }
                }
            ...
        }

这段加载过程将数据库中有用的数据，基本都加载到内存中来了，下面是各个数据的注释：

    // sBgItemsIdMap maps *all* the ItemInfos (shortcuts, folders, and widgets) created by
    // LauncherModel to their ids
    static final LongArrayMap<ItemInfo> sBgItemsIdMap = new LongArrayMap<>();

    // sBgWorkspaceItems is passed to bindItems, which expects a list of all folders and shortcuts
    //       created by LauncherModel that are directly on the home screen (however, no widgets or
    //       shortcuts within folders).
    static final ArrayList<ItemInfo> sBgWorkspaceItems = new ArrayList<ItemInfo>();

    // sBgAppWidgets is all LauncherAppWidgetInfo created by LauncherModel. Passed to bindAppWidget()
    static final ArrayList<LauncherAppWidgetInfo> sBgAppWidgets =
        new ArrayList<LauncherAppWidgetInfo>();

    // sBgFolders is all FolderInfos created by LauncherModel. Passed to bindFolders()
    static final LongArrayMap<FolderInfo> sBgFolders = new LongArrayMap<>();

    // sBgWorkspaceScreens is the ordered set of workspace screens.
    static final ArrayList<Long> sBgWorkspaceScreens = new ArrayList<Long>();

加载完数据，接下来就得将数据转化成View绑定到界面了，bindWorkspace()方法中可以看到，分别调了bindWorkspaceScreens、bindWorkspaceItems方法，而这两个方法中，又分别调到了Launcher.java的bindScreens、bindItems、bindAppWidget

        private void bindWorkspace(int synchronizeBindPage) {
            ...
            bindWorkspaceScreens(oldCallbacks, orderedScreenIds);

            Executor mainExecutor = new DeferredMainThreadExecutor();
            // Load items on the current page.
            bindWorkspaceItems(oldCallbacks, currentWorkspaceItems, currentAppWidgets, mainExecutor);

            // In case of validFirstPage, only bind the first screen, and defer binding the
            // remaining screens after first onDraw (and an optional the fade animation whichever
            // happens later).
            // This ensures that the first screen is immediately visible (eg. during rotation)
            // In case of !validFirstPage, bind all pages one after other.
            final Executor deferredExecutor =
                    validFirstPage ? new ViewOnDrawExecutor(mHandler) : mainExecutor;

            mainExecutor.execute(new Runnable() {
                @Override
                public void run() {
                    Callbacks callbacks = tryGetCallbacks(oldCallbacks);
                    if (callbacks != null) {
                        callbacks.finishFirstPageBind(
                                validFirstPage ? (ViewOnDrawExecutor) deferredExecutor : null);
                    }
                }
            });

            bindWorkspaceItems(oldCallbacks, otherWorkspaceItems, otherAppWidgets, deferredExecutor);
            ...
        }
        private void bindWorkspaceScreens(final Callbacks oldCallbacks,
                final ArrayList<Long> orderedScreens) {
            final Runnable r = new Runnable() {
                @Override
                public void run() {
                    Callbacks callbacks = tryGetCallbacks(oldCallbacks);
                    if (callbacks != null) {
                        callbacks.bindScreens(orderedScreens);
                    }
                }
            };
            runOnMainThread(r);
        }

        private void bindWorkspaceItems(final Callbacks oldCallbacks,
                final ArrayList<ItemInfo> workspaceItems,
                final ArrayList<LauncherAppWidgetInfo> appWidgets,
                final Executor executor) {

            // Bind the workspace items
            int N = workspaceItems.size();
            for (int i = 0; i < N; i += ITEMS_CHUNK) {
                final int start = i;
                final int chunkSize = (i+ITEMS_CHUNK <= N) ? ITEMS_CHUNK : (N-i);
                final Runnable r = new Runnable() {
                    @Override
                    public void run() {
                        Callbacks callbacks = tryGetCallbacks(oldCallbacks);
                        if (callbacks != null) {
                            callbacks.bindItems(workspaceItems, start, start+chunkSize,
                                    false);
                        }
                    }
                };
                executor.execute(r);
            }

            // Bind the widgets, one at a time
            N = appWidgets.size();
            for (int i = 0; i < N; i++) {
                final LauncherAppWidgetInfo widget = appWidgets.get(i);
                final Runnable r = new Runnable() {
                    public void run() {
                        Callbacks callbacks = tryGetCallbacks(oldCallbacks);
                        if (callbacks != null) {
                            callbacks.bindAppWidget(widget);
                        }
                    }
                };
                executor.execute(r);
            }
        }

通过下面代码可以看到，bindScreens()方法跟踪到最后，Workspace的 addView()方法，将一个CellLayout 添加到Workspace；而bindItems()方法跟踪到最后，走到了 CellLayout的 addViewToCellLayout()方法，被添加到CellLayout的ShortcutAndWidgetContainer 中去了。

    @Override
    public void bindScreens(ArrayList<Long> orderedScreenIds) {
        ...
        bindAddScreens(orderedScreenIds);
        ...
    }

    private void bindAddScreens(ArrayList<Long> orderedScreenIds) {
        int count = orderedScreenIds.size();
        for (int i = 0; i < count; i++) {
            long screenId = orderedScreenIds.get(i);
            if (!FeatureFlags.QSB_ON_FIRST_SCREEN || screenId != Workspace.FIRST_SCREEN_ID) {
                // No need to bind the first screen, as its always bound.
                mWorkspace.insertNewWorkspaceScreenBeforeEmptyScreen(screenId);
            }
        }
    }
    @Override
    public void bindItems(final ArrayList<ItemInfo> shortcuts, final int start, final int end,
                          final boolean forceAnimateIcons) {
        ...
        Workspace workspace = mWorkspace;
        long newShortcutsScreenId = -1;
        for (int i = start; i < end; i++) {
            final ItemInfo item = shortcuts.get(i);

            // Short circuit if we are loading dock items for a configuration which has no dock
            if (item.container == LauncherSettings.Favorites.CONTAINER_HOTSEAT &&
                    mHotseat == null) {
                continue;
            }

            final View view;
            switch (item.itemType) {
                case LauncherSettings.Favorites.ITEM_TYPE_APPLICATION:
                case LauncherSettings.Favorites.ITEM_TYPE_SHORTCUT:
                case LauncherSettings.Favorites.ITEM_TYPE_DEEP_SHORTCUT:
                    ShortcutInfo info = (ShortcutInfo) item;
                    view = createShortcut(info);
                    break;
                case LauncherSettings.Favorites.ITEM_TYPE_FOLDER:
                    view = FolderIcon.fromXml(R.layout.folder_icon, this,
                            (ViewGroup) workspace.getChildAt(workspace.getCurrentPage()),
                            (FolderInfo) item, mIconCache);
                    break;
                default:
                    throw new RuntimeException("Invalid Item Type");
            }
            ...
            workspace.addInScreenFromBind(view, item.container, item.screenId, item.cellX,
                    item.cellY, 1, 1);
            if (animateIcons) {
                // Animate all the applications up now
                view.setAlpha(0f);
                view.setScaleX(0f);
                view.setScaleY(0f);
                bounceAnims.add(createNewAppBounceAnimation(view, i));
                newShortcutsScreenId = item.screenId;
            }
        }
        ...
    }
    /**
     * Add the views for a widget to the workspace.
     *
     * Implementation of the method from LauncherModel.Callbacks.
     */
    public void bindAppWidget(final LauncherAppWidgetInfo item) {
        ...
        final LauncherAppWidgetProviderInfo appWidgetInfo;

        if (item.hasRestoreFlag(LauncherAppWidgetInfo.FLAG_PROVIDER_NOT_READY)) {
            // If the provider is not ready, bind as a pending widget.
            appWidgetInfo = null;
        } else if (item.hasRestoreFlag(LauncherAppWidgetInfo.FLAG_ID_NOT_VALID)) {
            // The widget id is not valid. Try to find the widget based on the provider info.
            appWidgetInfo = mAppWidgetManager.findProvider(item.providerName, item.user);
        } else {
            appWidgetInfo = mAppWidgetManager.getLauncherAppWidgetInfo(item.appWidgetId);
        }
        ...

        if (item.restoreStatus == LauncherAppWidgetInfo.RESTORE_COMPLETED) {
            ...
            item.minSpanX = appWidgetInfo.minSpanX;
            item.minSpanY = appWidgetInfo.minSpanY;
            addAppWidgetToWorkspace(
                    mAppWidgetHost.createView(this, item.appWidgetId, appWidgetInfo),
                    item, appWidgetInfo, false);
        } else {
            PendingAppWidgetHostView view = new PendingAppWidgetHostView(this, item, false);
            view.updateIcon(mIconCache);
            view.updateAppWidget(null);
            view.setOnClickListener(this);
            addAppWidgetToWorkspace(view, item, null, false);
        }
        ...
    }

    private void addAppWidgetToWorkspace(
            AppWidgetHostView hostView, LauncherAppWidgetInfo item,
            LauncherAppWidgetProviderInfo appWidgetInfo, boolean insert) {
        hostView.setTag(item);
        item.onBindAppWidget(this, hostView);

        hostView.setFocusable(true);
        hostView.setOnFocusChangeListener(mFocusHandler);

        mWorkspace.addInScreen(hostView, item.container, item.screenId,
                item.cellX, item.cellY, item.spanX, item.spanY, insert);

        if (!item.isCustomWidget()) {
            addWidgetToAutoAdvanceIfNeeded(hostView, appWidgetInfo);
        }
    }

    public void insertNewWorkspaceScreenBeforeEmptyScreen(long screenId) {
        // Find the index to insert this view into.  If the empty screen exists, then
        // insert it before that.
        int insertIndex = mScreenOrder.indexOf(EXTRA_EMPTY_SCREEN_ID);
        if (insertIndex < 0) {
            insertIndex = mScreenOrder.size();
        }
        insertNewWorkspaceScreen(screenId, insertIndex);
    }

    public CellLayout insertNewWorkspaceScreen(long screenId, int insertIndex) {
        if (mWorkspaceScreens.containsKey(screenId)) {
            throw new RuntimeException("Screen id " + screenId + " already exists!");
        }

        // Inflate the cell layout, but do not add it automatically so that we can get the newly
        // created CellLayout.
        CellLayout newScreen = (CellLayout) mLauncher.getLayoutInflater().inflate(
                        R.layout.workspace_screen, this, false /* attachToRoot */);
        newScreen.setOnLongClickListener(mLongClickListener);
        newScreen.setOnClickListener(mLauncher);
        newScreen.setSoundEffectsEnabled(false);
        mWorkspaceScreens.put(screenId, newScreen);
        mScreenOrder.add(insertIndex, screenId);
        addView(newScreen, insertIndex);

        if (mLauncher.getAccessibilityDelegate().isInAccessibleDrag()) {
            newScreen.enableAccessibleDrag(true, CellLayout.WORKSPACE_ACCESSIBILITY_DRAG);
        }

        return newScreen;
    }

    // At bind time, we use the rank (screenId) to compute x and y for hotseat items.
    // See implementation for parameter definition.
    public void addInScreenFromBind(View child, long container, long screenId, int x, int y,
            int spanX, int spanY) {
        addInScreen(child, container, screenId, x, y, spanX, spanY, false, true);
    }
    
    void addInScreen(View child, long container, long screenId, int x, int y, int spanX, int spanY,
            boolean insert) {
        addInScreen(child, container, screenId, x, y, spanX, spanY, insert, false);
    }
    void addInScreen(View child, long container, long screenId, int x, int y, int spanX, int spanY,
            boolean insert, boolean computeXYFromRank) {
        ...
        final CellLayout layout;
        if (container == LauncherSettings.Favorites.CONTAINER_HOTSEAT) {
            layout = mLauncher.getHotseat().getLayout();
            ...
        } else {
            layout = getScreenWithId(screenId);
            ...
        }
        ...
        if (!layout.addViewToCellLayout(child, insert ? 0 : -1, childId, lp, markCellsAsOccupied)) {
            // TODO: This branch occurs when the workspace is adding views
            // outside of the defined grid
            // maybe we should be deleting these items from the LauncherModel?
            Log.e(TAG, "Failed to add to item at (" + lp.cellX + "," + lp.cellY + ") to CellLayout");
        }
        ...
    }

    public boolean addViewToCellLayout(View child, int index, int childId, LayoutParams params,
            boolean markCells) {
        final LayoutParams lp = params;

        // Hotseat icons - remove text
        if (child instanceof BubbleTextView) {
            BubbleTextView bubbleChild = (BubbleTextView) child;
            bubbleChild.setTextVisibility(!mIsHotseat);
        }

        child.setScaleX(getChildrenScale());
        child.setScaleY(getChildrenScale());

        // Generate an id for each view, this assumes we have at most 256x256 cells
        // per workspace screen
        if (lp.cellX >= 0 && lp.cellX <= mCountX - 1 && lp.cellY >= 0 && lp.cellY <= mCountY - 1) {
            // If the horizontal or vertical span is set to -1, it is taken to
            // mean that it spans the extent of the CellLayout
            if (lp.cellHSpan < 0) lp.cellHSpan = mCountX;
            if (lp.cellVSpan < 0) lp.cellVSpan = mCountY;

            child.setId(childId);
            if (LOGD) {
                Log.d(TAG, "Adding view to ShortcutsAndWidgetsContainer: " + child);
            }
            mShortcutsAndWidgets.addView(child, index, lp);

            if (markCells) markCellsAsOccupiedForView(child);

            return true;
        }
        return false;
    }

到这里，Launcher第一次启动时 加载快捷方式、Widget的流程就结束了。