?桌面應用圖標流程

前言

本人工作上碰到這么一個需求，開發一款濾鏡引擎，將桌面上所有的圖標進行統一的濾鏡化，這就需要了解一下整個桌面去取圖標的過程，了解了整個過程，找到真正拿圖標的地方，在真正取圖標的地方將圖片進行替換，或者濾鏡化，之前分析情況，現在整理下，與大家分享。本文所用的代碼，是基于Android 5.1

桌面組件介紹

一級菜單

WorkSpace：他是一個ViewGroup，要想在桌面上顯示東西，就得往這個ViewGroup里添加自己的View

BubbleTextView：他是一個TextView，上方是圖標，下方是名稱，在桌面上的圖標都是由這個類表示

FolderIcon：他也是一個ViewGroup，用來表示桌面上的文件夾圖標，里面添加了縮略處理過的bitmap，他的背景圖片就是文件夾的形狀

HotSeat： 他是個FrameLayout，是桌面下方的固定快捷區，包含了幾個常用的圖標，中間的AllApp按鈕是固定位置，也是一個TextView

抽屜頁面 組件

PagedView：他是一個viewgroup，代表進入抽屜頁后的界面，應用圖標需要添加到這個viewgoup里面才能顯示，一個或幾個PagedView 承載了手機上所有的應用圖標

PagedViewIcon：他是一個TextView，和BubblTextView一樣，只是在抽屜容器里換了個名字

桌面加載圖標流程

先來看一張流程圖

桌面Activity 也就是Launcher.java 類，該類里面維護了一個 LauncherModel,該對象會在onCreate 方法中去調用startLoader() 方法，

下面看一下startLoader() 方法的源碼，

public void startLoader(boolean isLaunching, int synchronousBindPage) { synchronized (mLock) { if (DEBUG_LOADERS) { Log.d(TAG, "startLoader isLaunching=" + isLaunching); } // Clear any deferred bind-runnables from the synchronized load process // We must do this before any loading/binding is scheduled below. mDeferredBindRunnables.clear(); // Don't bother to start the thread if we know it's not going to do anything if (mCallbacks != null && mCallbacks.get() != null) { // If there is already one running, tell it to stop. // also, don't downgrade isLaunching if we're already running isLaunching = isLaunching || stopLoaderLocked(); // 這搞了一個異步任務去加載 mLoaderTask = new LoaderTask(mApp.getContext(), isLaunching); if (synchronousBindPage > -1 && mAllAppsLoaded && mWorkspaceLoaded) { mLoaderTask.runBindSynchronousPage(synchronousBindPage); } else { sWorkerThread.setPriority(Thread.NORM_PRIORITY); sWorker.post(mLoaderTask); } } } }

我們看到，這里面有個關鍵的類，loaderTask,見名只義，可以猜到這里面會起一個線程，去加載一些資源。看看里面去加載什么

LoaderTask.java

可以看到LoaderTask實現了Runnable接口，直接去看該類的run() 方法

public void run() { boolean isUpgrade = false; synchronized (mLock) { 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: { // Elevate priority when Home launches for the first time to avoid // starving at boot time. Staring at a blank home is not cool. synchronized (mLock) { if (DEBUG_LOADERS) Log.d(TAG, "Setting thread priority to " + (mIsLaunching ? "DEFAULT" : "BACKGROUND")); android.os.Process.setThreadPriority(mIsLaunching ? Process.THREAD_PRIORITY_DEFAULT : Process.THREAD_PRIORITY_BACKGROUND); } if (DEBUG_LOADERS) Log.d(TAG, "step 1: loading workspace"); //加載一級菜單的方法 isUpgrade = loadAndBindWorkspace(); if (mStopped) { break keep_running; } // Whew! Hard work done. Slow us down, and wait until the UI thread has // settled down. synchronized (mLock) { if (mIsLaunching) { if (DEBUG_LOADERS) Log.d(TAG, "Setting thread priority to BACKGROUND"); android.os.Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND); } } waitForIdle(); // second step if (DEBUG_LOADERS) Log.d(TAG, "step 2: loading all apps"); //加載二級菜單里面的方法 loadAndBindAllApps(); // Restore the default thread priority after we are done loading items synchronized (mLock) { android.os.Process.setThreadPriority(Process.THREAD_PRIORITY_DEFAULT); } } // Update the saved icons if necessary if (DEBUG_LOADERS) Log.d(TAG, "Comparing loaded icons to database icons"); synchronized (sBgLock) { for (Object key : sBgDbIconCache.keySet()) { updateSavedIcon(mContext, (ShortcutInfo) key, sBgDbIconCache.get(key)); } sBgDbIconCache.clear(); } if (AppsCustomizePagedView.DISABLE_ALL_APPS) { // Ensure that all the applications that are in the system are // represented on the home screen. if (!UPGRADE_USE_MORE_APPS_FOLDER || !isUpgrade) { verifyApplications(); } } // 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; } }

可以看到在該類中主要有兩個方法，

loadAndBindWorkSpace(), WorkSpace是一級菜單里面的容器類，該方法是加載一及菜單的方法

loadAndBindAllapp() ,這是抽屜內二級菜單的加載方法

下面著重分析下這兩個方法的加載流程

loadAndBindWorkSpace()

這里加載主要分為兩個流程一個是 loadWorkSpace 另一個是 bindWorkSpace,可以看下源代碼

private boolean loadAndBindWorkspace() { mIsLoadingAndBindingWorkspace = true; // Load the workspace if (DEBUG_LOADERS) { Log.d(TAG, "loadAndBindWorkspace mWorkspaceLoaded=" + mWorkspaceLoaded); } boolean isUpgradePath = false; if (!mWorkspaceLoaded) { isUpgradePath = loadWorkspace(); synchronized (LoaderTask.this) { if (mStopped) { return isUpgradePath; } mWorkspaceLoaded = true; } } // Bind the workspace bindWorkspace(-1, isUpgradePath); return isUpgradePath; }

可以看到并沒有直接去加載，而是先判斷了一些條件，然后去加載

loadWorkSpace() 方法比較長大概分為三步，

初始化后面要用到的對象實例

final long t = DEBUG_LOADERS ? SystemClock.uptimeMillis() : 0; final Context context = mContext; final ContentResolver contentResolver = context.getContentResolver(); final PackageManager manager = context.getPackageManager(); final AppWidgetManager widgets = AppWidgetManager.getInstance(context); final boolean isSafeMode = manager.isSafeMode(); LauncherAppState app = LauncherAppState.getInstance(); DeviceProfile grid = app.getDynamicGrid().getDeviceProfile(); int countX = (int) grid.numColumns; int countY = (int) grid.numRows;

加載默認配置，并保存數據庫中

synchronized public void loadDefaultFavoritesIfNecessary(int origWorkspaceResId) { String spKey = LauncherAppState.getSharedPreferencesKey(); SharedPreferences sp = getContext().getSharedPreferences(spKey, Context.MODE_PRIVATE); if (sp.getBoolean(EMPTY_DATABASE_CREATED, false)) { int workspaceResId = origWorkspaceResId; // Use default workspace resource if none provided //如果workspaceResId=0，就會加載默認的配置(default_workspace_xxx.xml)，并保存到數據庫中 if (workspaceResId == 0) { workspaceResId = sp.getInt(DEFAULT_WORKSPACE_RESOURCE_ID, R.xml.default_workspace); } // Populate favorites table with initial favorites SharedPreferences.Editor editor = sp.edit(); editor.remove(EMPTY_DATABASE_CREATED); if (origWorkspaceResId != 0) { editor.putInt(DEFAULT_WORKSPACE_RESOURCE_ID, origWorkspaceResId); } mOpenHelper.loadFavorites(mOpenHelper.getWritableDatabase(), workspaceResId); mOpenHelper.setFlagJustLoadedOldDb(); editor.commit(); } }

讀取數據庫，獲取需要加載的應用快捷方式

此段代碼較多，就是去讀取數據庫的一些操作，具體過程是根據一些不同的type 存到不同的list中。

bindWorkSpace()

應用信息讀取完之后，剛才的幾個變量中就存儲了該信息，然后將其綁定到workspace中去，這個過程也是很復雜的

創建局部變量，將全局變量的信息復制過來，單獨進行操作

ArrayList workspaceItems = new ArrayList(); ArrayList appWidgets = new ArrayList(); HashMap folders = new HashMap(); HashMap itemsIdMap = new HashMap(); ArrayList orderedScreenIds = new ArrayList(); synchronized (sBgLock) { workspaceItems.addAll(sBgWorkspaceItems); appWidgets.addAll(sBgAppWidgets); folders.putAll(sBgFolders); itemsIdMap.putAll(sBgItemsIdMap); orderedScreenIds.addAll(sBgWorkspaceScreens); } final boolean isLoadingSynchronously = synchronizeBindPage != PagedView.INVALID_RESTORE_PAGE; int currScreen = isLoadingSynchronously ? synchronizeBindPage : oldCallbacks.getCurrentWorkspaceScreen(); if (currScreen >= orderedScreenIds.size()) { // There may be no workspace screens (just hotseat items and an empty page). currScreen = PagedView.INVALID_RESTORE_PAGE; } final int currentScreen = currScreen;// 當前screen final long currentScreenId = currentScreen < 0 ? INVALID_SCREEN_ID : orderedScreenIds.get(currentScreen);// 當前screen id // Load all the items that are on the current page first (and in the process, unbind // all the existing workspace items before we call startBinding() below. unbindWorkspaceItemsOnMainThread();// 先解除綁定

根據item中的screenID將items分成當前screen和其他screen，并進行排序

// Separate the items that are on the current screen, and all the other remaining items ArrayList currentWorkspaceItems = new ArrayList();// 存放當前workspace上的items ArrayList otherWorkspaceItems = new ArrayList();// 存放除當前workspace之外的items ArrayList currentAppWidgets = new ArrayList();// 存放當前workspace上的appwidgets ArrayList otherAppWidgets = new ArrayList();// 存放除當前workspace之外的appwidgets HashMap currentFolders = new HashMap();// 存放當前workspace上的folder HashMap otherFolders = new HashMap();// 存放除當前workspace之外的folder filterCurrentWorkspaceItems(currentScreenId, workspaceItems, currentWorkspaceItems, otherWorkspaceItems);// 過濾items，區分當前screen和其他screen上的items filterCurrentAppWidgets(currentScreenId, appWidgets, currentAppWidgets, otherAppWidgets);// 同上 filterCurrentFolders(currentScreenId, itemsIdMap, folders, currentFolders, otherFolders);// 同上 sortWorkspaceItemsSpatially(currentWorkspaceItems);// 對workspace上的items進行排序，按照從上到下和從左到右的順序 sortWorkspaceItemsSpatially(otherWorkspaceItems);// 同上

runnable執行塊，告訴workspace要開始綁定items了，startBinding方法在Launcher中實現，做一些清除工作

// Tell the workspace that we're about to start binding items r = new Runnable() { public void run() { Callbacks callbacks = tryGetCallbacks(oldCallbacks); if (callbacks != null) { callbacks.startBinding(); } } }; runOnMainThread(r, MAIN_THREAD_BINDING_RUNNABLE);

可以看一下實現類launcher中startBinding()方法

public void startBinding() { // If we're starting binding all over again, clear any bind calls we'd postponed in // the past (see waitUntilResume) -- we don't need them since we're starting binding // from scratch again mBindOnResumeCallbacks.clear(); // Clear the workspace because it's going to be rebound mWorkspace.clearDropTargets(); mWorkspace.removeAllWorkspaceScreens(); mWidgetsToAdvance.clear(); if (mHotseat != null) { mHotseat.resetLayout(); } }

可以看到主要做的是清除和重置工作

綁定workspace screen

bindWorkspaceScreens(oldCallbacks, orderedScreenIds); 具體實現在launcher中

Workspace綁定完成之后，就是將items、widgets和folders放到上面去

loadAndBindAllapp()

可以看到加載過程也是分為兩步：如果所有app已經加載過了，就只需要綁定就行了，否則的話，加載所有app，第一次啟動肯定是加載所有的，我們按照這種情況來分析

1.獲取需要顯示到Launcher中的app列表，創建app圖標

private void loadAndBindAllApps() { if (DEBUG_LOADERS) { Log.d(TAG, "loadAndBindAllApps mAllAppsLoaded=" + mAllAppsLoaded); } if (!mAllAppsLoaded) { loadAllApps(); synchronized (LoaderTask.this) { if (mStopped) { return; } mAllAppsLoaded = true; } } else { onlyBindAllApps(); } }

loadAllApps()

final long loadTime = DEBUG_LOADERS ? SystemClock.uptimeMillis() : 0; final Callbacks oldCallbacks = mCallbacks.get(); if (oldCallbacks == null) { // This launcher has exited and nobody bothered to tell us. Just bail. Log.w(TAG, "LoaderTask running with no launcher (loadAllApps)"); return; } final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null); mainIntent.addCategory(Intent.CATEGORY_LAUNCHER); final List profiles = mUserManager.getUserProfiles(); // Clear the list of apps mBgAllAppsList.clear();// 清除所有app列表 SharedPreferences prefs = mContext.getSharedPreferences( LauncherAppState.getSharedPreferencesKey(), Context.MODE_PRIVATE); for (UserHandleCompat user : profiles) { // Query for the set of apps final long qiaTime = DEBUG_LOADERS ? SystemClock.uptimeMillis() : 0; List apps = mLauncherApps.getActivityList(null, user);// 獲取需要顯示在Launcher上的activity列表 if (DEBUG_LOADERS) { Log.d(TAG, "getActivityList took " + (SystemClock.uptimeMillis()-qiaTime) + "ms for user " + user); Log.d(TAG, "getActivityList got " + apps.size() + " apps for user " + user); } // Fail if we don't have any apps // TODO: Fix this. Only fail for the current user. if (apps == null || apps.isEmpty()) {// 沒有需要顯示的，直接返回 return; } // Sort the applications by name final long sortTime = DEBUG_LOADERS ? SystemClock.uptimeMillis() : 0; Collections.sort(apps, new LauncherModel.ShortcutNameComparator(mLabelCache));// 排序 if (DEBUG_LOADERS) { Log.d(TAG, "sort took " + (SystemClock.uptimeMillis()-sortTime) + "ms"); } // Create the ApplicationInfos for (int i = 0; i < apps.size(); i++) { LauncherActivityInfoCompat app = apps.get(i); // This builds the icon bitmaps. mBgAllAppsList.add(new AppInfo(mContext, app, user, mIconCache, mLabelCache));// 創建應用圖標對象，并添加到所有APP列表中 } if (ADD_MANAGED_PROFILE_SHORTCUTS && !user.equals(UserHandleCompat.myUserHandle())) { // Add shortcuts for packages which were installed while launcher was dead. String shortcutsSetKey = INSTALLED_SHORTCUTS_SET_PREFIX + mUserManager.getSerialNumberForUser(user); Set packagesAdded = prefs.getStringSet(shortcutsSetKey, Collections.EMPTY_SET); HashSet newPackageSet = new HashSet(); for (LauncherActivityInfoCompat info : apps) { String packageName = info.getComponentName().getPackageName(); if (!packagesAdded.contains(packageName) && !newPackageSet.contains(packageName)) { InstallShortcutReceiver.queueInstallShortcut(info, mContext); } newPackageSet.add(packageName); } prefs.edit().putStringSet(shortcutsSetKey, newPackageSet).commit(); } } // Huh? Shouldn't this be inside the Runnable below? final ArrayList added = mBgAllAppsList.added;// 獲取自上次更新（notify()廣播）后新增加的應用清單，如果是開機初次啟動Launcher，那么added就是mBgAllAppsList mBgAllAppsList.added = new ArrayList();// 將AllAppsList的added清空，不影響后續新增的app // Post callback on main thread mHandler.post(new Runnable() { public void run() { final long bindTime = SystemClock.uptimeMillis(); final Callbacks callbacks = tryGetCallbacks(oldCallbacks); if (callbacks != null) { callbacks.bindAllApplications(added); if (DEBUG_LOADERS) { Log.d(TAG, "bound " + added.size() + " apps in " + (SystemClock.uptimeMillis() - bindTime) + "ms"); } } else { Log.i(TAG, "not binding apps: no Launcher activity"); } } }); if (DEBUG_LOADERS) { Log.d(TAG, "Icons processed in " + (SystemClock.uptimeMillis() - loadTime) + "ms"); }

綁定app--bindAllApplications

public void bindAllApplications(final ArrayList apps) { if (LauncherAppState.isDisableAllApps()) {// 判斷是否禁用所有app,就是所有應用都顯示在一級目錄 if (mIntentsOnWorkspaceFromUpgradePath != null) { if (LauncherModel.UPGRADE_USE_MORE_APPS_FOLDER) { getHotseat().addAllAppsFolder(mIconCache, apps, mIntentsOnWorkspaceFromUpgradePath, Launcher.this, mWorkspace); } mIntentsOnWorkspaceFromUpgradePath = null; } if (mAppsCustomizeContent != null) { mAppsCustomizeContent.onPackagesUpdated( LauncherModel.getSortedWidgetsAndShortcuts(this)); } } else { if (mAppsCustomizeContent != null) { mAppsCustomizeContent.setApps(apps); mAppsCustomizeContent.onPackagesUpdated(LauncherModel.getSortedWidgetsAndShortcuts(this)); } } if (mLauncherCallbacks != null) { mLauncherCallbacks.bindAllApplications(apps); } }

可以看到無論是一級桌面拿圖標，還是抽屜頁面拿圖標，都是去走，IconCache的getIcon()方法，

IconCache

getIcon()

public Bitmap getIcon(ComponentName component, ResolveInfo resolveInfo, HashMap labelCache) { synchronized (mCache) { if (resolveInfo == null || component == null) { return null; } CacheEntry entry = cacheLocked(component, resolveInfo, labelCache); return entry.icon; } }

這里判斷一下條件，會去走cacheLocked() 方法

cacheLocked()

private CacheEntry cacheLocked(ComponentName componentName, ResolveInfo info, HashMap labelCache) { CacheEntry entry = mCache.get(componentName); if (entry == null) { entry = new CacheEntry(); mCache.put(componentName, entry); ComponentName key = LauncherModel.getComponentNameFromResolveInfo(info); if (labelCache != null && labelCache.containsKey(key)) { entry.title = labelCache.get(key).toString(); } else { entry.title = info.loadLabel(mPackageManager).toString(); if (labelCache != null) { labelCache.put(key, entry.title); } } if (entry.title == null) { entry.title = info.activityInfo.name; } entry.icon = Utilities.createIconBitmap( getFullResIcon(info), mContext); } return entry; }

這個方法里面。就是最終去拿圖標的方法，里面去拿一些必要信息，去給entry賦值

?