SystemUI之USB2（Framework UEvent -> SystemUI）
第二节 Framework UEvent -> SystemUI
逻辑主要在Framework里面的NotificationManagerService.java
UsbDeviceManager.java 到framework的NotificationManagerService.java，这里面涉及到通知的分类和排序，通知的显示风格等等，然后通过NotificationListenerService来通知SystemUI.
在SystemUI注册服务，然后在framework层回调，贯通SystemUI以及Framework。
UsbDeviceManager.java中——》
mNotificationManager.notifyAsUser(null, id, notification,
UserHandle.ALL);
调用NotificationManager的notifyAsUser（）往上上传notification，跟到方法里面看下，
路径：framework/base/core/java/android/app/NotificationManager.java
INotificationManager service = getService();//获取IBinder对象
我们看下Notification的addFieldsFromContext方法做了哪些事情：路径：frameworks/base/core/java/android/app/Notification.javapublic static void addFieldsFromContext(Context context, Notification notification) {
addFieldsFromContext(context.getApplicationInfo(), context.getUserId(), notification);
}
/**
* @hide
*/
public static void addFieldsFromContext(ApplicationInfo ai, int userId,
Notification notification) {
notification.extras.putParcelable(EXTRA_BUILDER_APPLICATION_INFO, ai);//"android.appinfo"
notification.extras.putInt(EXTRA_ORIGINATING_USERID, userId);//"android.originatingUserId"
} addFieldsFromContext方法主要实现将当前应用的ApplicationInfo对象保存到“android.appinfo”字段，将当前的userId保存到“android.originatingUserId”字段中。
fixLegacySmalIcon，notify函数会判断notification是否有small icon，如果没有设icon或small icon，用notify方法时会抛出异常。fixLegacySmallIcon方法如下： private void fixLegacySmallIcon(Notification n, String pkg) {
if (n.getSmallIcon() == null && n.icon != 0) {
n.setSmallIcon(Icon.createWithResource(pkg, n.icon));
}
}
完成上面的操作后，调用通知管理类NotificationManagerService的enqueueNotificationWithTag方法，
@Override
public void enqueueNotificationWithTag(String pkg, String opPkg, String tag, int id,
Notification notification, int[] idOut, int userId) throws RemoteException {
enqueueNotificationInternal(pkg, opPkg, Binder.getCallingUid(),
Binder.getCallingPid(), tag, id, notification, idOut, userId);
}
我们看到在enqueueNotificationWithTag方法中调用了enqueueNotificationInternal方法，这里就是通知处理的核心了。
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void enqueueNotificationInternal(final String pkg, final String opPkg, final int callingUid,
final int callingPid, final String tag, final int id, final Notification notification,
int[] idOut, int incomingUserId) {
if (DBG) {
Slog.v(TAG, "enqueueNotificationInternal: pkg=" + pkg + " id=" + id
+ " notification=" + notification);
}
checkCallerIsSystemOrSameApp(pkg);
// 校验UID
final boolean isSystemNotification = isUidSystem(callingUid) || ("android".equals(pkg));
final boolean isNotificationFromListener = mListeners.isListenerPackage(pkg);
final int userId = ActivityManager.handleIncomingUser(callingPid,
callingUid, incomingUserId, true, false, "enqueueNotification", pkg);
final UserHandle user = new UserHandle(userId);
// Fix the notification as best we can.
try {
final ApplicationInfo ai = getContext().getPackageManager().getApplicationInfoAsUser(
pkg, PackageManager.MATCH_DEBUG_TRIAGED_MISSING,
(userId == UserHandle.USER_ALL) ? UserHandle.USER_SYSTEM : userId);
Notification.addFieldsFromContext(ai, userId, notification);
} catch (NameNotFoundException e) {
Slog.e(TAG, "Cannot create a context for sending app", e);
return;
}
mUsageStats.registerEnqueuedByApp(pkg);
// Limit the number of notifications that any given package except the android
// package or a registered listener can enqueue. Prevents DOS attacks and deals with leaks.
// 这里会做一个限制，除了系统级别的应用之外，其他应用的notification数量会做限制,用来防止DOS攻击导致的泄露
if (!isSystemNotification && !isNotificationFromListener) {
synchronized (mNotificationList) {
final float appEnqueueRate = mUsageStats.getAppEnqueueRate(pkg);
if (appEnqueueRate > mMaxPackageEnqueueRate) {
mUsageStats.registerOverRateQuota(pkg);
final long now = SystemClock.elapsedRealtime();
if ((now - mLastOverRateLogTime) > MIN_PACKAGE_OVERRATE_LOG_INTERVAL) {
Slog.e(TAG, "Package enqueue rate is " + appEnqueueRate
+ ". Shedding events. package=" + pkg);
mLastOverRateLogTime = now;
}
return;
}
int count = 0;
final int N = mNotificationList.size();
for (int i=0; i<N; i++) {
final NotificationRecord r = mNotificationList.get(i);
if (r.sbn.getPackageName().equals(pkg) && r.sbn.getUserId() == userId) {
if (r.sbn.getId() == id && TextUtils.equals(r.sbn.getTag(), tag)) {
break; // Allow updating existing notification
}
count++;
if (count >= MAX_PACKAGE_NOTIFICATIONS) {// 同一个应用发送notification数量不能超过50
mUsageStats.registerOverCountQuota(pkg);
Slog.e(TAG, "Package has already posted " + count
+ " notifications. Not showing more. package=" + pkg);
return;
}
}
}
}
}
if (pkg == null || notification == null) {//通知不能为空
throw new IllegalArgumentException("null not allowed: pkg=" + pkg
+ " id=" + id + " notification=" + notification);
}
// Whitelist pending intents.
if (notification.allPendingIntents != null) {
final int intentCount = notification.allPendingIntents.size();
if (intentCount > 0) {
final ActivityManagerInternal am = LocalServices
.getService(ActivityManagerInternal.class);
final long duration = LocalServices.getService(
DeviceIdleController.LocalService.class).getNotificationWhitelistDuration();
for (int i = 0; i < intentCount; i++) {
PendingIntent pendingIntent = notification.allPendingIntents.valueAt(i);
if (pendingIntent != null) {
am.setPendingIntentWhitelistDuration(pendingIntent.getTarget(), duration);
}
}
}
}
// Sanitize inputs
notification.priority = clamp(notification.priority, Notification.PRIORITY_MIN,
Notification.PRIORITY_MAX);
// setup local book-keeping
// 验证完条件后，将前面传递进来的Notification封装成一个StatusBarNotification对象,
final StatusBarNotification n = new StatusBarNotification(
pkg, opPkg, id, tag, callingUid, callingPid, 0, notification,
user);
// 封装NotificationRecord对象
final NotificationRecord r = new NotificationRecord(getContext(), n);
mHandler.post(new EnqueueNotificationRunnable(userId, r));
idOut[0] = id;
}
开启线程，异步处理。 private class EnqueueNotificationRunnable implements Runnable {
private final NotificationRecord r;
private final int userId;
EnqueueNotificationRunnable(int userId, NotificationRecord r) {
this.userId = userId;
this.r = r;
};
@Override
public void run() {
synchronized (mNotificationList) {
final StatusBarNotification n = r.sbn;
if (DBG) Slog.d(TAG, "EnqueueNotificationRunnable.run for: " + n.getKey());
NotificationRecord old = mNotificationsByKey.get(n.getKey());
if (old != null) {
// Retain ranking information from previous record
r.copyRankingInformation(old);
}
final int callingUid = n.getUid();
final int callingPid = n.getInitialPid();
final Notification notification = n.getNotification();
final String pkg = n.getPackageName();
final int id = n.getId();
final String tag = n.getTag();
final boolean isSystemNotification = isUidSystem(callingUid) ||
("android".equals(pkg));
// Handle grouped notifications and bail out early if we
// can to avoid extracting signals.
handleGroupedNotificationLocked(r, old, callingUid, callingPid);
// This conditional is a dirty hack to limit the logging done on
// behalf of the download manager without affecting other apps.
if (!pkg.equals("com.android.providers.downloads")
|| Log.isLoggable("DownloadManager", Log.VERBOSE)) {
int enqueueStatus = EVENTLOG_ENQUEUE_STATUS_NEW;
if (old != null) {
enqueueStatus = EVENTLOG_ENQUEUE_STATUS_UPDATE;
}
EventLogTags.writeNotificationEnqueue(callingUid, callingPid,
pkg, id, tag, userId, notification.toString(),
enqueueStatus);
}
mRankingHelper.extractSignals(r);
final boolean isPackageSuspended = isPackageSuspendedForUser(pkg, callingUid);
// blocked apps 判断pkg是否可以显示通知
if (r.getImportance() == NotificationListenerService.Ranking.IMPORTANCE_NONE
|| !noteNotificationOp(pkg, callingUid) || isPackageSuspended) {
if (!isSystemNotification) {//不拦截系统通知
if (isPackageSuspended) {
Slog.e(TAG, "Suppressing notification from package due to package "
+ "suspended by administrator.");
mUsageStats.registerSuspendedByAdmin(r);
} else {
Slog.e(TAG, "Suppressing notification from package by user request.");
mUsageStats.registerBlocked(r);
}
return;
}
}
// tell the ranker service about the notification
if (mRankerServices.isEnabled()) {
mRankerServices.onNotificationEnqueued(r);
// TODO delay the code below here for 100ms or until there is an answer
}
// 获取是否已经发送过此notification
int index = indexOfNotificationLocked(n.getKey());
if (index < 0) {
// 如果是新发送的notification,就走新增流程.
mNotificationList.add(r);
mUsageStats.registerPostedByApp(r);
} else {
//如果有发送过，就获取oldNtificationRecord，后面走更新流程 mStatusBar.updateNotification(r.statusBarKey, n)
old = mNotificationList.get(index);
mNotificationList.set(index, r);
mUsageStats.registerUpdatedByApp(r, old);
// Make sure we don't lose the foreground service state.
notification.flags |=
old.getNotification().flags & Notification.FLAG_FOREGROUND_SERVICE;
r.isUpdate = true;
}
Slog.d(TAG, "NotificationRecord, r = "+r);
mNotificationsByKey.put(n.getKey(), r);
// Ensure if this is a foreground service that the proper additional
// flags are set.
if ((notification.flags & Notification.FLAG_FOREGROUND_SERVICE) != 0) {
notification.flags |= Notification.FLAG_ONGOING_EVENT
| Notification.FLAG_NO_CLEAR;
}
applyZenModeLocked(r);
mRankingHelper.sort(mNotificationList);//将mNotificationList排序
// 如果notification设置了smallIcon，调用所有NotificationListeners的notifyPostedLocked方法，
// 通知有新的notification，传入的参数为上面封装成的StatusBarNotification对象.
if (notification.getSmallIcon() != null) {
StatusBarNotification oldSbn = (old != null) ? old.sbn : null;
mListeners.notifyPostedLocked(n, oldSbn);
} else {
Slog.e(TAG, "Not posting notification without small icon: " + notification);
if (old != null && !old.isCanceled) {
mListeners.notifyRemovedLocked(n);
}
// ATTENTION: in a future release we will bail out here
// so that we do not play sounds, show lights, etc. for invalid
// notifications
Slog.e(TAG, "WARNING: In a future release this will crash the app: "
+ n.getPackageName());
}
// buzzBeepBlinkLocked方法负责对消息进行处理。
// 通知status bar显示该notification,确认是否需要声音，震动和闪光，如果需要，那么就发出声音，震动和闪光
buzzBeepBlinkLocked(r);
}
}
} 到这里，就开始进入SystemUI了。
// 如果notification设置了smallIcon，调用所有NotificationListeners的notifyPostedLocked方法， // 通知有新的notification，传入的参数为上面封装成的StatusBarNotification对象. if (notification.getSmallIcon() != null) { StatusBarNotification oldSbn = (old != null) ? old.sbn : null; mListeners.notifyPostedLocked(n, oldSbn); } else { Slog.e(TAG, "Not posting notification without small icon: " + notification); if (old != null && !old.isCanceled) { mListeners.notifyRemovedLocked(n); } // ATTENTION: in a future release we will bail out here // so that we do not play sounds, show lights, etc. for invalid // notifications Slog.e(TAG, "WARNING: In a future release this will crash the app: " + n.getPackageName()); }
其中，mListeners为NotificationListeners，为内部类。查看方法notifyPostedLocked（）
/** * asynchronously notify all listeners about a new notification * * <p> * Also takes care of removing a notification that has been visible to a listener before, * but isn't anymore. */ public void notifyPostedLocked(StatusBarNotification sbn, StatusBarNotification oldSbn) { // Lazily initialized snapshots of the notification. TrimCache trimCache = new TrimCache(sbn); 通知所有的监听者关于这个新通知， for (final ManagedServiceInfo info : mServices) { boolean sbnVisible = isVisibleToListener(sbn, info); boolean oldSbnVisible = oldSbn != null ? isVisibleToListener(oldSbn, info) : false; // This notification hasn't been and still isn't visible -> ignore. if (!oldSbnVisible && !sbnVisible) { continue; } final NotificationRankingUpdate update = makeRankingUpdateLocked(info); // This notification became invisible -> remove the old one. if (oldSbnVisible && !sbnVisible) { final StatusBarNotification oldSbnLightClone = oldSbn.cloneLight(); mHandler.post(new Runnable() { @Override public void run() { notifyRemoved(info, oldSbnLightClone, update); } }); continue; } final StatusBarNotification sbnToPost = trimCache.ForListener(info); mHandler.post(new Runnable() { @Override public void run() { notifyPosted(info, sbnToPost, update); } }); } }
然后在notifyPosted()方法里面推送通知，我们来看下这个方法：
private void notifyPosted(final ManagedServiceInfo info, final StatusBarNotification sbn, NotificationRankingUpdate rankingUpdate) { final INotificationListener listener = (INotificationListener)info.service; StatusBarNotificationHolder sbnHolder = new StatusBarNotificationHolder(sbn); try { listener.onNotificationPosted(sbnHolder, rankingUpdate); } catch (RemoteException ex) { Log.e(TAG, "unable to notify listener (posted): " + listener, ex); } }
然后监听者调用onNotificationPosted（）继续往上推送
路径：frameworks/base/core/java/android/service/notification/INotificationListener.aidl
INotificationManager.aidl BaseStatusBar.java
目录：frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/BaseStatusBar.java
在BaseStatusBar.java 里面注册NotificationListenerService。
try { mNotificationListener.registerAsSystemService(mContext, new ComponentName(mContext.getPackageName(), getClass().getCanonicalName()), UserHandle.USER_ALL); } catch (RemoteException e) { Log.e(TAG, "Unable to register notification listener", e); }！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！！
在registerAsSystemService中调用registerListener方法。这个方法在INotificationManager.stub中声明了，而INotificationManager.stub 跟NotificationManagerService进行了绑定。so 跟进了NotificationManagerService.java
frameworks/base/core/java/android/app/INotificationManager.aidl
framework/base/services/core/java/com/android/server/notification/NotificationManagerService.java
在NotificationManagerService.java里面
private final IBinder mService = new INotificationManager.Stub()
----> NotificationManagerService.java在实例化INotificationManager.stub 对象的时候，对registerListener 进行了override。在这个方法中，它首先去调用enforceSystemOrSystemUI，接着才去registerService。很显然，想要的答案就在enforceSystemOrSystemUI 中。so 跟进enforceSystemOrSystemUI。这个方法呢，也是在实例化INotificationManager.stub 对象mService的时候，对其 进行了override。
这样NotificationManagerService和NotificationListenerService连接上，可以吧消息传到systemUI进去。