Android4.4 Framework分析——Android默认Home应用Launcher3的加载过程分析

本文主要介绍Android4.4默认Home应用Launcher3的启动过程和Launcher3的数据加载过程。Launcher的启动是开机时，ActivityManagerService准备好后开始的，下图是它的启动序列图：



step1，SystemServer中，ActivityManagerService准备好了。

step3，

boolean resumeTopActivitiesLocked(ActivityStack targetStack, ActivityRecord target,
Bundle targetOptions) {
if (targetStack == null) {
targetStack = getFocusedStack(); //获得mHomeStack
}
boolean result = false;
for (int stackNdx = mStacks.size() - 1; stackNdx >= 0; --stackNdx) {
final ActivityStack stack = mStacks.get(stackNdx);
if (isFrontStack(stack)) {
if (stack == targetStack) {
result = stack.resumeTopActivityLocked(target, targetOptions);
} else {
stack.resumeTopActivityLocked(null);
}
}
}
return result;
}

mStacks中已经添加过mHomeStack，mStacks的内容介绍请查看 Android4.4 Framework分析——ActivityManagerService的启动和对Activity的管理
，目前mStacks中只有mHomeStack这个ActivityStacK。

step6，

boolean startHomeActivityLocked(int userId) {
if (mHeadless) {
// Added because none of the other calls to ensureBootCompleted seem to fire
// when running headless.
ensureBootCompleted();
return false;
}
Intent intent = getHomeIntent(); //HOME intent
ActivityInfo aInfo =
resolveActivityInfo(intent, STOCK_PM_FLAGS, userId);//查找home应用信息
if (aInfo != null) {
intent.setComponent(new ComponentName(
aInfo.applicationInfo.packageName, aInfo.name));
// Don't do this if the home app is currently being
// instrumented.
aInfo = new ActivityInfo(aInfo);
aInfo.applicationInfo = getAppInfoForUser(aInfo.applicationInfo, userId);
ProcessRecord app = getProcessRecordLocked(aInfo.processName,
aInfo.applicationInfo.uid, true);//home应用未启动，返回null
if (app == null || app.instrumentationClass == null) {
intent.setFlags(intent.getFlags() | Intent.FLAG_ACTIVITY_NEW_TASK);
mStackSupervisor.startHomeActivity(intent, aInfo); //step7
}
}

return true;
}

Intent getHomeIntent() {
Intent intent = new Intent(mTopAction, mTopData != null ? Uri.parse(mTopData) : null);
intent.setComponent(mTopComponent);
if (mFactoryTest != SystemServer.FACTORY_TEST_LOW_LEVEL) {
intent.addCategory(Intent.CATEGORY_HOME);//Home应用的标志
}
return intent;
}

step7~step10，Activity的启动过程参照Android4.4 Framework分析——Launcher中启动应用程序(startActivity)的过程

的step14之后的过程。

step11~step14，开始异步加载应用图标，工作线程sWorkerThread。

step15~step20，加载workspace的图标，step16读取LauncherProvider的Favorites数据，favorites表的数据是Launcher数据库创建时从default_workspace.xml解析读取的。step18绑定图标信息。

step22，睡眠等待空闲进程，然后加载主菜单的所有app图标。

step23，从睡眠中醒来，准备加载所有app图标，包括widget等。

step24，

private void loadAllApps() {
final long loadTime = DEBUG_LOADERS ? SystemClock.uptimeMillis() : 0;
.....
final PackageManager packageManager = mContext.getPackageManager();
final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null); //在PackageManagerService查询所有要显示在桌面上的app
mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);

// Clear the list of apps
mBgAllAppsList.clear();

// Query for the set of apps
final long qiaTime = DEBUG_LOADERS ? SystemClock.uptimeMillis() : 0;
List<ResolveInfo> apps = packageManager.queryIntentActivities(mainIntent, 0);
if (DEBUG_LOADERS) {
Log.d(TAG, "queryIntentActivities took "
+ (SystemClock.uptimeMillis()-qiaTime) + "ms");
Log.d(TAG, "queryIntentActivities got " + apps.size() + " apps");
}
// Fail if we don't have any apps
if (apps == null || apps.isEmpty()) {
return;
}
// Sort the applications by name
final long sortTime = DEBUG_LOADERS ? SystemClock.uptimeMillis() : 0;
Collections.sort(apps,
new LauncherModel.ShortcutNameComparator(packageManager, mLabelCache));//按应用名称排序

// Create the ApplicationInfos
for (int i = 0; i < apps.size(); i++) {
ResolveInfo app = apps.get(i);
// This builds the icon bitmaps.
mBgAllAppsList.add(new AppInfo(packageManager, app,
mIconCache, mLabelCache));
}

// Huh? Shouldn't this be inside the Runnable below?
final ArrayList<AppInfo> added = mBgAllAppsList.added;
mBgAllAppsList.added = new ArrayList<AppInfo>();

// 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); //step26，绑定
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");
}
}
});
}

右键复制图片地址，在浏览器中打开即可查看大图。

未完待续，有不对的地方，请指正。