在之前我们分析了Android6.0系统在启动时安装应用程序的过程，这些应用程序安装好之后，Launcher应用就负责把它们在桌面上展示出来。
一、AMS启动Launcher
Launcher应用是在AMS的systemReady方法中直接调用startHomeActivityLocked启动的，下面是systemReady启动Launcher的代码。
startHomeActivityLocked(mCurrentUserId, "systemReady");我们来看下这个函数，先调用了getHomeIntent方法来获取Intent，然后也是调用resolveActivityInfo函数从PKMS获取ActivityInfo，接着当进程没有启动的话，调用ActivityStackSupervisor的startHomeActivity函数
boolean startHomeActivityLocked(int userId, String reason) {
if (mFactoryTest == FactoryTest.FACTORY_TEST_LOW_LEVEL
&& mTopAction == null) {
// We are running in factory test mode, but unable to find
// the factory test app, so just sit around displaying the
// error message and don't try to start anything.
return false;
}
Intent intent = getHomeIntent();//获取intent
ActivityInfo aInfo =
resolveActivityInfo(intent, STOCK_PM_FLAGS, userId);//获取ActivityInfo
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);
if (app == null || app.instrumentationClass == null) {//进程没有启动调用
EventLog.writeEvent(EventLogTags.AM_PROC_START,"AMS -> startHomeActivityLocked startHomeActivity then startActivityLock : "+ aInfo.processName);
intent.setFlags(intent.getFlags() | Intent.FLAG_ACTIVITY_NEW_TASK);
mStackSupervisor.startHomeActivity(intent, aInfo, reason);
}
}
return true;
}
我们先来看看getHomeIntent这个函数。
Intent getHomeIntent() {
Intent intent = new Intent(mTopAction, mTopData != null ? Uri.parse(mTopData) : null);
intent.setComponent(mTopComponent);
if (mFactoryTest != FactoryTest.FACTORY_TEST_LOW_LEVEL) {
intent.addCategory(Intent.CATEGORY_HOME);
}
return intent;
}
然后我们来看下ActivityStackSupervisor的startHomeActivity函数，它也是调用了startActivityLocked来启动Activity的，在之前的博客分析过这个函数这里我们就不介绍了。
void startHomeActivity(Intent intent, ActivityInfo aInfo, String reason) {
moveHomeStackTaskToTop(HOME_ACTIVITY_TYPE, reason);
startActivityLocked(null /* caller */, intent, null /* resolvedType */, aInfo,
null /* voiceSession */, null /* voiceInteractor */, null /* resultTo */,
null /* resultWho */, 0 /* requestCode */, 0 /* callingPid */, 0 /* callingUid */,
null /* callingPackage */, 0 /* realCallingPid */, 0 /* realCallingUid */,
0 /* startFlags */, null /* options */, false /* ignoreTargetSecurity */,
false /* componentSpecified */,
null /* outActivity */, null /* container */, null /* inTask */);
if (inResumeTopActivity) {
// 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.
scheduleResumeTopActivities();
}
}
二、Launcher启动
接着我们来看下Launcher的AndroidManifest.xml，我们看下其主Activity有一个category为android.intent.category.HOME
<application
android:name="com.android.launcher2.LauncherApplication"
android:label="@string/application_name"
android:icon="@mipmap/ic_launcher_home"
android:hardwareAccelerated="true"
android:largeHeap="@bool/config_largeHeap"
android:supportsRtl="true">
<activity
android:name="com.android.launcher2.Launcher"
android:launchMode="singleTask"
android:clearTaskOnLaunch="true"
android:stateNotNeeded="true"
android:resumeWhilePausing="true"
android:theme="@style/Theme"
android:windowSoftInputMode="adjustPan"
android:screenOrientation="nosensor">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.HOME" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.MONKEY"/>
</intent-filter>
</activity>
......
在Launcher.java的onCreate函数中调用了mModel.startLoader函数
protected void onCreate(Bundle savedInstanceState) {
......
if (!mRestoring) {
if (sPausedFromUserAction) {
// If the user leaves launcher, then we should just load items asynchronously when
// they return.
mModel.startLoader(true, -1);
} else {
// We only load the page synchronously if the user rotates (or triggers a
// configuration change) while launcher is in the foreground
mModel.startLoader(true, mWorkspace.getCurrentPage());
}
}
......
startLoader函数会post一个Runnable消息，我们来看下它的run方法
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();
mLoaderTask = new LoaderTask(mApp, isLaunching);
if (synchronousBindPage > -1 && mAllAppsLoaded && mWorkspaceLoaded) {
mLoaderTask.runBindSynchronousPage(synchronousBindPage);
} else {
sWorkerThread.setPriority(Thread.NORM_PRIORITY);
sWorker.post(mLoaderTask);
}
}
}
}
在它的run方法中会调用loadAndBindAllApps函数，在loadAndBindAllApps函数中又会调用loadAllAppsByBatch函数
public void run() {
synchronized (mLock) {
mIsLoaderTaskRunning = true;
}
final Callbacks cbk = mCallbacks.get();
final boolean loadWorkspaceFirst = cbk != null ? (!cbk.isAllAppsVisible()) : true;
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"));
Process.setThreadPriority(mIsLaunching
? Process.THREAD_PRIORITY_DEFAULT : Process.THREAD_PRIORITY_BACKGROUND);
}
// First step. Load workspace first, this is necessary since adding of apps from
// managed profile in all apps is deferred until onResume. See http://b/17336902.
if (loadWorkspaceFirst) {
if (DEBUG_LOADERS) Log.d(TAG, "step 1: loading workspace");
loadAndBindWorkspace();
} else {
Log.d(TAG, "step 1: special: loading all apps");
loadAndBindAllApps();
}
我们先来看下loadAndBindAllApps函数，这个函数先进入while循环，然后调用了LauncherApps的getActivityList函数，后面又会调用callbacks的bindAllApplications
private void loadAllAppsByBatch() {
final long t = DEBUG_LOADERS ? SystemClock.uptimeMillis() : 0;
......
mBgAllAppsList.clear();
final int profileCount = profiles.size();
for (int p = 0; p < profileCount; p++) {
......
while (i < N && !mStopped) {
if (i == 0) {
final long qiaTime = DEBUG_LOADERS ? SystemClock.uptimeMillis() : 0;
apps = mLauncherApps.getActivityList(null, user);
......
mHandler.post(new Runnable() {
public void run() {
final long t = SystemClock.uptimeMillis();
if (callbacks != null) {
if (firstProfile) {
callbacks.bindAllApplications(added);
} else {
callbacks.bindAppsAdded(added);
}
if (DEBUG_LOADERS) {
Log.d(TAG, "bound " + added.size() + " apps in "
+ (SystemClock.uptimeMillis() - t) + "ms");
}
} else {
Log.i(TAG, "not binding apps: no Launcher activity");
}
}
});
......
我们先来看LauncherApps的getActivityList函数，它先用mService成员变量调用getLauncherActivities函数获取到list<ResolveInfo>，然后封装在ArrayList<LauncherActivityInfo> 中。
public List<LauncherActivityInfo> getActivityList(String packageName, UserHandle user) {
List<ResolveInfo> activities = null;
try {
activities = mService.getLauncherActivities(packageName, user);
} catch (RemoteException re) {
throw new RuntimeException("Failed to call LauncherAppsService");
}
if (activities == null) {
return Collections.EMPTY_LIST;
}
ArrayList<LauncherActivityInfo> lais = new ArrayList<LauncherActivityInfo>();
final int count = activities.size();
for (int i = 0; i < count; i++) {
ResolveInfo ri = activities.get(i);
long firstInstallTime = 0;
try {
firstInstallTime = mPm.getPackageInfo(ri.activityInfo.packageName,
PackageManager.GET_UNINSTALLED_PACKAGES).firstInstallTime;
} catch (NameNotFoundException nnfe) {
// Sorry, can't find package
}
LauncherActivityInfo lai = new LauncherActivityInfo(mContext, ri, user,
firstInstallTime);
if (DEBUG) {
Log.v(TAG, "Returning activity for profile " + user + " : "
+ lai.getComponentName());
}
lais.add(lai);
}
return lais;
}
其service是class LauncherAppsImpl extends ILauncherApps.Stub 下面是getLauncherActivities函数，肯定也是通过PKMS来获取相关Activity的ResolveInfo的。
@Override
public List<ResolveInfo> getLauncherActivities(String packageName, UserHandle user)
throws RemoteException {
ensureInUserProfiles(user, "Cannot retrieve activities for unrelated profile " + user);
if (!isUserEnabled(user)) {
return new ArrayList<ResolveInfo>();
}
final Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);
mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);
mainIntent.setPackage(packageName);
long ident = Binder.clearCallingIdentity();
try {
List<ResolveInfo> apps = mPm.queryIntentActivitiesAsUser(mainIntent, 0 /* flags */,
user.getIdentifier());
return apps;
} finally {
Binder.restoreCallingIdentity(ident);
}
}
最后回调Launcher.java的bindAllApplications函数，最后在这个函数中可以在桌面上展示系统中所有的应用程序了。
public void bindAllApplications(final ArrayList<ApplicationInfo> apps) {
Runnable setAllAppsRunnable = new Runnable() {
public void run() {
if (mAppsCustomizeContent != null) {
mAppsCustomizeContent.setApps(apps);
}
}
};
// Remove the progress bar entirely; we could also make it GONE
// but better to remove it since we know it's not going to be used
View progressBar = mAppsCustomizeTabHost.
findViewById(R.id.apps_customize_progress_bar);
if (progressBar != null) {
((ViewGroup)progressBar.getParent()).removeView(progressBar);
// We just post the call to setApps so the user sees the progress bar
// disappear-- otherwise, it just looks like the progress bar froze
// which doesn't look great
mAppsCustomizeTabHost.post(setAllAppsRunnable);
} else {
// If we did not initialize the spinner in onCreate, then we can directly set the
// list of applications without waiting for any progress bars views to be hidden.
setAllAppsRunnable.run();
}
}
三、显示应用图标
我们再来看下Launcher的onClick函数，当调用showWorkspace可以显示所有应用的图标。
public 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;
}
if (!mWorkspace.isFinishedSwitchingState()) {
return;
}
Object tag = v.getTag();
if (tag instanceof ShortcutInfo) {
// Open shortcut
final Intent intent = ((ShortcutInfo) tag).intent;
int[] pos = new int[2];
v.getLocationOnScreen(pos);
intent.setSourceBounds(new Rect(pos[0], pos[1],
pos[0] + v.getWidth(), pos[1] + v.getHeight()));
boolean success = startActivitySafely(v, intent, tag);
if (success && v instanceof BubbleTextView) {
mWaitingForResume = (BubbleTextView) v;
mWaitingForResume.setStayPressed(true);
}
} else if (tag instanceof FolderInfo) {
if (v instanceof FolderIcon) {
FolderIcon fi = (FolderIcon) v;
handleFolderClick(fi);
}
} else if (v == mAllAppsButton) {
if (isAllAppsVisible()) {
showWorkspace(true);
} else {
onClickAllAppsButton(v);
}
}
}
在showWorkspace中会显示所有的图标
void showWorkspace(boolean animated, Runnable onCompleteRunnable) {
if (mState != State.WORKSPACE) {
boolean wasInSpringLoadedMode = (mState == State.APPS_CUSTOMIZE_SPRING_LOADED);
mWorkspace.setVisibility(View.VISIBLE);
hideAppsCustomizeHelper(State.WORKSPACE, animated, false, onCompleteRunnable);
// Show the search bar (only animate if we were showing the drop target bar in spring
// loaded mode)
if (mSearchDropTargetBar != null) {
mSearchDropTargetBar.showSearchBar(wasInSpringLoadedMode);
}
// We only need to animate in the dock divider if we're going from spring loaded mode
showDockDivider(animated && wasInSpringLoadedMode);
// Set focus to the AppsCustomize button
if (mAllAppsButton != null) {
mAllAppsButton.requestFocus();
}
}
mWorkspace.flashScrollingIndicator(animated);
// Change the state *after* we've called all the transition code
mState = State.WORKSPACE;
// Resume the auto-advance of widgets
mUserPresent = true;
updateRunning();
// Send an accessibility event to announce the context change
getWindow().getDecorView()
.sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED);
}
而点击应用图标，最终会调用Launcher.java的startActivitySafely来启动应用。这里调用的startActivity就是Activity的startActivity函数。
boolean startActivitySafely(View v, Intent intent, Object tag) {
boolean success = false;
try {
success = startActivity(v, intent, tag);
} catch (ActivityNotFoundException e) {
Toast.makeText(this, R.string.activity_not_found, Toast.LENGTH_SHORT).show();
Log.e(TAG, "Unable to launch. tag=" + tag + " intent=" + intent, e);
}
return success;
}
