Android 7.0 NotificationManagerService源码分析(应用层App，Fragmework中Service层，SystemUI系统App)

缺乏、安全感 2022-05-19 06:21 180阅读 0赞

前言：

> 国产ROM定制化比较复杂，最近在做Notification的适配工作。了解Notification源码走向，才知道国产ROM系统对Notification拦截点，找到相应办法绕过。话题有些绕远了，这里还是讲解Notification源码走向。

本篇，介绍，如何从应用层，到远程的Server进程(系统进程)，再到SystemUI(系提APP)渲染展示Notification。

#### **1. 应用层中发出关于Notification的信息** ####

`android.app.NotificationManager`类中：

创建好的Notification，调用`notify()` 加入

public void notify(int id, Notification notification){
            notify(null, id, notification);
    }

接下来，调用多态同名方法:

public void notify(String tag, int id, Notification notification){
            notifyAsUser(tag, id, notification, new UserHandle(UserHandle.myUserId()));
    }

接下来，调用`notifyAsUser`:

public void notifyAsUser(String tag, int id, Notification notification, UserHandle user){
            int[] idOut = new int[1];
            INotificationManager service = getService();
            String pkg = mContext.getPackageName();
            //为Notification添加一些关于程序的信息
            Notification.addFieldsFromContext(mContext, notification);
            if (notification.sound != null) {
                notification.sound = notification.sound.getCanonicalUri();
                if (StrictMode.vmFileUriExposureEnabled()) {
                    notification.sound.checkFileUriExposed("Notification.sound");
                }
            }
            //为Notifcation设置SmallIcon
            fixLegacySmallIcon(notification, pkg);
            if (mContext.getApplicationInfo().targetSdkVersion > Build.VERSION_CODES.LOLLIPOP_MR1) {
                if (notification.getSmallIcon() == null) {
                    throw new IllegalArgumentException("Invalid notification (no valid small icon): "
                            + notification);
                }
            }
            if (localLOGV) Log.v(TAG, pkg + ": notify(" + id + ", " + notification + ")");
            final Notification copy = Builder.maybeCloneStrippedForDelivery(notification);
            try {
                //远程调用 NotificationManagerService
                service.enqueueNotificationWithTag(pkg, mContext.getOpPackageName(), tag, id,
                        copy, idOut, user.getIdentifier());
                if (id != idOut[0]) {
                    Log.w(TAG, "notify: id corrupted: sent " + id + ", got back " + idOut[0]);
                }
            } catch (RemoteException e) {
                throw e.rethrowFromSystemServer();
            }
        }

先看下，Notification类中的`addFieldsFromContext()`：添加一些程序的基本信息

/** * @hide */
        public 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);
            notification.extras.putInt(EXTRA_ORIGINATING_USERID, userId);
        }

再来看下getService()：

/** @hide */
    static public INotificationManager getService(){
            if (sService != null) {
                return sService;
            }
            IBinder b = ServiceManager.getService("notification");
            sService = INotificationManager.Stub.asInterface(b);
            return sService;
    }

可知，INotifcationManger是一个aidl生成的java类，通过binder调用到对应的远程服务中。

#### **2. 远程的Server进程** ####

在`com.android.server.notification.NotificationManagerService`类中：

private final IBinder mService = new INotificationManager.Stub() {
            //.....省略部分源码
    
            /** * 远程客户端，跨进程调用到这里。 */
            @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);
            }
    }

接下来，看下`enqueueNotificationInternal()`:

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) {
            //.... 检查Notification的个数限制，和相应Pending intents白名单的源码，这里省略
    
            //将Notification相关信息到StatusBarNotification中
            final StatusBarNotification n = new StatusBarNotification(
                    pkg, opPkg, id, tag, callingUid, callingPid, 0, notification,
                    user);
            final NotificationRecord r = new NotificationRecord(getContext(), n);
            mHandler.post(new EnqueueNotificationRunnable(userId, r));
        }

接下来，在看下EnqueueNotificationRunnable类：

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;
                    //...app拦截规则，设置Notication为前台服务的flag，这里省略对应源码。
    
                    if (notification.getSmallIcon() != null) {
                        StatusBarNotification oldSbn = (old != null) ? old.sbn : null;
                        //通知所有的
                        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());
                    }
                    // 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);
                }
            }
        }

接下来，继续查看在NotificationManagerService.NotificationListeners类中：

public class NotificationListeners extends ManagedServices { 
            //....省略部分源码
    
            /** * 异步通知所有监听器，关于新的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);
                // for循环方式，跨进程,通知到每一个INotificationLister
                for (final ManagedServiceInfo info : mServices) {
                    boolean sbnVisible = isVisibleToListener(sbn, info);
                    boolean oldSbnVisible = oldSbn != null ? isVisibleToListener(oldSbn, info) : false;
                  //省略Notification不可见检查操作，和更新，这里省略该源码
                   final StatusBarNotification sbnToPost =  trimCache.ForListener(info);
                    mHandler.post(new Runnable() {
                        @Override
                        public void run() {
                            notifyPosted(info, sbnToPost, update);
                        }
                    });
                }
            }      
    }

接下来，查看NotificationManagerService中`notifyPosted()`:

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);
                }
    }

INotificationListener 是一个aidl生成Java类，用于远程调用。实际上INotificationListener对象是NotificationListenerSevice类中的NotificationListenerWrapper对象。详情,查看[Android 7.0 NotificationListenerService源码分析][Android 7.0 NotificationListenerService]

在来看一下NotificationListeners，是一个用于保持追踪监听器的MangedServices对象。 那INotificationLister又是如何添加进去的呢？

搜索NotificationManagerService会发现，

private final IBinder mService = new INotificationManager.Stub() {
            @Override
        public void registerListener(final INotificationListener listener,
                    final ComponentName component, final int userid) {
                enforceSystemOrSystemUI("INotificationManager.registerListener");
                mListeners.registerService(listener, component, userid);
       }
    
     }

顺带来，查看下`buzzBeepBlinkLocked()`： 对Notification各种设置参数

@VisibleForTesting
    void buzzBeepBlinkLocked(NotificationRecord record) {
            boolean buzz = false;
            boolean beep = false;
            boolean blink = false;
            final Notification notification = record.sbn.getNotification();
            //.......省略部分源码
    
            // light
            // release the light
            boolean wasShowLights = mLights.remove(key);
            if ((notification.flags & Notification.FLAG_SHOW_LIGHTS) != 0 && aboveThreshold
                    && ((record.getSuppressedVisualEffects()
                    & NotificationListenerService.SUPPRESSED_EFFECT_SCREEN_OFF) == 0)) {
                mLights.add(key);
                updateLightsLocked();
                if (mUseAttentionLight) {
                    mAttentionLight.pulse();
                }
                blink = true;
            } else if (wasShowLights) {
                updateLightsLocked();
            }
            if (buzz || beep || blink) {
                if (((record.getSuppressedVisualEffects()
                        & NotificationListenerService.SUPPRESSED_EFFECT_SCREEN_OFF) != 0)) {
                    if (DBG) Slog.v(TAG, "Suppressed SystemUI from triggering screen on");
                } else {
                    EventLogTags.writeNotificationAlert(key,
                            buzz ? 1 : 0, beep ? 1 : 0, blink ? 1 : 0);
                    mHandler.post(mBuzzBeepBlinked);
                }
            }
        }

#### **3. SystemUI渲染展示Notification** ####

SystemUI系统app中BaseStatubar类:

public void start() {
        //....省略部分源码
    
        // Set up the initial notification state.
        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);
            }
    }
    
     private final NotificationListenerService mNotificationListener =
                new NotificationListenerService() {
            // ... 省略部分源码
            @Override
            public void onNotificationPosted(final StatusBarNotification sbn,
                    final RankingMap rankingMap) {
                if (DEBUG) Log.d(TAG, "onNotificationPosted: " + sbn);
                if (sbn != null) {
                    mHandler.post(new Runnable() {
                        @Override
                        public void run() {
                            // ... 省略部分源码
                            if (isUpdate) {
                                updateNotification(sbn, rankingMap);
                            } else {
                                addNotification(sbn, rankingMap, null /* oldEntry */);
                            }
                        }
                    });
                }
            }
    
        };

接下来，查看`addNotification()`:

该方法是一个抽象方法，在PhoenStatubar中具体实现：

@Override
        public void addNotification(StatusBarNotification notification, RankingMap ranking,
                Entry oldEntry) {
            if (DEBUG) Log.d(TAG, "addNotification key=" + notification.getKey());
    
            mNotificationData.updateRanking(ranking);
            Entry shadeEntry = createNotificationViews(notification);
            if (shadeEntry == null) {
                return;
            }
            boolean isHeadsUped = shouldPeek(shadeEntry);
            if (isHeadsUped) {
                mHeadsUpManager.showNotification(shadeEntry);
                // Mark as seen immediately
                setNotificationShown(notification);
            }
    
            if (!isHeadsUped && notification.getNotification().fullScreenIntent != null) {
                if (shouldSuppressFullScreenIntent(notification.getKey())) {
                    if (DEBUG) {
                        Log.d(TAG, "No Fullscreen intent: suppressed by DND: " + notification.getKey());
                    }
                } else if (mNotificationData.getImportance(notification.getKey())
                        < NotificationListenerService.Ranking.IMPORTANCE_MAX) {
                    if (DEBUG) {
                        Log.d(TAG, "No Fullscreen intent: not important enough: "
                                + notification.getKey());
                    }
                } else {
                    // Stop screensaver if the notification has a full-screen intent.
                    // (like an incoming phone call)
                    awakenDreams();
    
                    // not immersive & a full-screen alert should be shown
                    if (DEBUG)
                        Log.d(TAG, "Notification has fullScreenIntent; sending fullScreenIntent");
                    try {
                        EventLog.writeEvent(EventLogTags.SYSUI_FULLSCREEN_NOTIFICATION,
                                notification.getKey());
                        notification.getNotification().fullScreenIntent.send();
                        shadeEntry.notifyFullScreenIntentLaunched();
                        MetricsLogger.count(mContext, "note_fullscreen", 1);
                    } catch (PendingIntent.CanceledException e) {
                    }
                }
            }
            addNotificationViews(shadeEntry, ranking);
            // Recalculate the position of the sliding windows and the titles.
            setAreThereNotifications();
        }

接下来，查看BaseStatuBar的`addNotificationViews()`:

protected void addNotificationViews(Entry entry, RankingMap ranking) {
            if (entry == null) {
                return;
            }
            // Add the expanded view and icon.
            mNotificationData.add(entry, ranking);
            updateNotifications();
        }

将通知添加到NotificationData中，调用更新方法。

接下来,查看`updateNotifications()`:

@Override
        protected void updateNotifications() {
            mNotificationData.filterAndSort();
    
            updateNotificationShade();
            mIconController.updateNotificationIcons(mNotificationData);
        }

将通知排序,更新通知栏，和通知栏的icon。

接下来，查看`updateNotificationShade`：

private void updateNotificationShade() {
            if (mStackScroller == null) return;
    
            // Do not modify the notifications during collapse.
            if (isCollapsing()) {
                addPostCollapseAction(new Runnable() {
                    @Override
                    public void run() {
                        updateNotificationShade();
                    }
                });
                return;
            }
    
            ArrayList<Entry> activeNotifications = mNotificationData.getActiveNotifications();
            ArrayList<ExpandableNotificationRow> toShow = new ArrayList<>(activeNotifications.size());
            final int N = activeNotifications.size();
            for (int i=0; i<N; i++) {
                Entry ent = activeNotifications.get(i);
                int vis = ent.notification.getNotification().visibility;
    
                // Display public version of the notification if we need to redact.
                final boolean hideSensitive =
                        !userAllowsPrivateNotificationsInPublic(ent.notification.getUserId());
                boolean sensitiveNote = vis == Notification.VISIBILITY_PRIVATE;
                boolean sensitivePackage = packageHasVisibilityOverride(ent.notification.getKey());
                boolean sensitive = (sensitiveNote && hideSensitive) || sensitivePackage;
                boolean showingPublic = sensitive && isLockscreenPublicMode();
                if (showingPublic) {
                    updatePublicContentView(ent, ent.notification);
                }
                ent.row.setSensitive(sensitive, hideSensitive);
                if (ent.autoRedacted && ent.legacy) {
                    // TODO: Also fade this? Or, maybe easier (and better), provide a dark redacted form
                    // for legacy auto redacted notifications.
                    if (showingPublic) {
                        ent.row.setShowingLegacyBackground(false);
                    } else {
                        ent.row.setShowingLegacyBackground(true);
                    }
                }
                if (mGroupManager.isChildInGroupWithSummary(ent.row.getStatusBarNotification())) {
                    ExpandableNotificationRow summary = mGroupManager.getGroupSummary(
                            ent.row.getStatusBarNotification());
                    List<ExpandableNotificationRow> orderedChildren =
                            mTmpChildOrderMap.get(summary);
                    if (orderedChildren == null) {
                        orderedChildren = new ArrayList<>();
                        mTmpChildOrderMap.put(summary, orderedChildren);
                    }
                    orderedChildren.add(ent.row);
                } else {
                    toShow.add(ent.row);
                }
    
            }
    
            ArrayList<ExpandableNotificationRow> toRemove = new ArrayList<>();
            for (int i=0; i< mStackScroller.getChildCount(); i++) {
                View child = mStackScroller.getChildAt(i);
                if (!toShow.contains(child) && child instanceof ExpandableNotificationRow) {
                    toRemove.add((ExpandableNotificationRow) child);
                }
            }
    
            for (ExpandableNotificationRow remove : toRemove) {
                if (mGroupManager.isChildInGroupWithSummary(remove.getStatusBarNotification())) {
                    // we are only transfering this notification to its parent, don't generate an animation
                    mStackScroller.setChildTransferInProgress(true);
                }
                if (remove.isSummaryWithChildren()) {
                    remove.removeAllChildren();
                }
                mStackScroller.removeView(remove);
                mStackScroller.setChildTransferInProgress(false);
            }
    
            removeNotificationChildren();
    
            for (int i=0; i<toShow.size(); i++) {
                View v = toShow.get(i);
                if (v.getParent() == null) {
                    mStackScroller.addView(v);
                }
            }
    
            addNotificationChildrenAndSort();
    
            // So after all this work notifications still aren't sorted correctly.
            // Let's do that now by advancing through toShow and mStackScroller in
            // lock-step, making sure mStackScroller matches what we see in toShow.
            int j = 0;
            for (int i = 0; i < mStackScroller.getChildCount(); i++) {
                View child = mStackScroller.getChildAt(i);
                if (!(child instanceof ExpandableNotificationRow)) {
                    // We don't care about non-notification views.
                    continue;
                }
    
                ExpandableNotificationRow targetChild = toShow.get(j);
                if (child != targetChild) {
                    // Oops, wrong notification at this position. Put the right one
                    // here and advance both lists.
                    mStackScroller.changeViewPosition(targetChild, i);
                }
                j++;
    
            }
    
            // clear the map again for the next usage
            mTmpChildOrderMap.clear();
    
            updateRowStates();
            updateSpeedbump();
            updateClearAll();
            updateEmptyShadeView();
    
            updateQsExpansionEnabled();
            mShadeUpdates.check();
        }

一个通知对应一个ExpandableNotificationRow，添加到NotificationStackScrollLayout类。

接下来，看下StatusBarIconController类中`updateNotificationIcons()`

public void updateNotificationIcons(NotificationData notificationData) {
           mNotificationIconAreaController.updateNotificationIcons(notificationData);
    }

接下来，看下NotificationIconAreaController类中`updateNotificationIcons()`更新显示出来Notification

/** * Updates the notifications with the given list of notifications to display. */
        public void updateNotificationIcons(NotificationData notificationData) {
            final LinearLayout.LayoutParams params = generateIconLayoutParams();
    
            ArrayList<NotificationData.Entry> activeNotifications =
                    notificationData.getActiveNotifications();
            final int size = activeNotifications.size();
            ArrayList<StatusBarIconView> toShow = new ArrayList<>(size);
    
            // Filter out ambient notifications and notification children.
            for (int i = 0; i < size; i++) {
                NotificationData.Entry ent = activeNotifications.get(i);
                if (shouldShowNotification(ent, notificationData)) {
                    toShow.add(ent.icon);
                }
            }
    
            ArrayList<View> toRemove = new ArrayList<>();
            for (int i = 0; i < mNotificationIcons.getChildCount(); i++) {
                View child = mNotificationIcons.getChildAt(i);
                if (!toShow.contains(child)) {
                    toRemove.add(child);
                }
            }
    
            final int toRemoveCount = toRemove.size();
            for (int i = 0; i < toRemoveCount; i++) {
                mNotificationIcons.removeView(toRemove.get(i));
            }
    
            for (int i = 0; i < toShow.size(); i++) {
                View v = toShow.get(i);
                if (v.getParent() == null) {
                    mNotificationIcons.addView(v, i, params);
                }
            }
    
            // Re-sort notification icons
            final int childCount = mNotificationIcons.getChildCount();
            for (int i = 0; i < childCount; i++) {
                View actual = mNotificationIcons.getChildAt(i);
                StatusBarIconView expected = toShow.get(i);
                if (actual == expected) {
                    continue;
                }
                mNotificationIcons.removeView(expected);
                mNotificationIcons.addView(expected, i);
            }
    
            applyNotificationIconsTint();
        }

**总结一下，Notification的流程走向：**

App运用层：

> NotificationManager.notify
> 
> –>NotificationManager.notifyAsUser()
> 
> –>INotificationManager.enqueueNotificationWithTag()

Fragmewrok框架中远程server进程：

> NotificationManagerService.enqueueNotificationWithTag()
> 
> –>NotificationManagerService.enqueueNotificationInternal()
> 
> –>NotificationManagerService.EnqueueNotificationRunnable
> 
> –>NotificationManagerService.PostNotificationRunnable
> 
> –>NotificationManagerService.NotificationListeners.notifyPostedLocked()
> 
> –>NotificationManagerService.NotificationListeners.notifyPosted()

SystemUI.apk中：

> BaseStatusBar.INotificationListener.onNotificationPosted()
> 
> –>PhoneStatusBar.addNotification()
> 
> –>BaseStatusBar.addNotificationViews()
> 
> –>PhoneStatusBar.updateNotifications()

--------------------

**资源参考**：

*  [https://www.2cto.com/kf/201707/656464.html][https_www.2cto.com_kf_201707_656464.html]
 *  [https://blog.csdn.net/self\_study/article/details/51055769][https_blog.csdn.net_self_study_article_details_51055769]

[Android 7.0 NotificationListenerService]: https://blog.csdn.net/hexingen/article/details/81147536
[https_www.2cto.com_kf_201707_656464.html]: https://www.2cto.com/kf/201707/656464.html
[https_blog.csdn.net_self_study_article_details_51055769]: https://blog.csdn.net/self_study/article/details/51055769