android显示过程,Android 桌面加载图标过程分析
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
總結
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