Notification framework层的处理流程分析

转载自：http://fortianwei.iteye.com/blog/1180020

相关文件:

framework/base/core/java/android/app/NotificationManager.java

framework/base/services/java/com/android/server/NotificationManagerService.java{@hide} extends INotificationManager.Stub

framework/base/services/java/com/android/server/StatusBarManagerService.java  extends IStatusBarService.Stub

 

 

framework/base/core/java/com/android/internal/statusbar/StatusBarNotification  implements Parcelable

framework/base/core/java/com/android/internal/statusbar/IStatusBar.aidl

framework/base/core/java/com/android/internal/statusbar/IStatusBarService.aidl

framework/base/core/java/com/android/internal/statusbar/StatusBarNotification.aidl

 

framework/base/packages/SystemUI/src/com/android/systemui/statusbar/StatusBarService.java extends Service implements CommandQueue.Callbacks

framework/base/packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java extends IStatusBar.Stub

1>.系统启动的时候：framework/base/services/java/com/android/server/SystemServer.java中：

  try {
         Slog.i(TAG, "Status Bar");
         statusBar = new StatusBarManagerService(context);
         ServiceManager.addService(Context.STATUS_BAR_SERVICE, statusBar);
 } catch (Throwable e) {
          Slog.e(TAG, "Failure starting StatusBarManagerService", e);
 }

 try {
         Slog.i(TAG, "Notification Manager");
          notification = new NotificationManagerService(context, statusBar, lights);

          ServiceManager.addService(Context.NOTIFICATION_SERVICE, notification);
 } catch (Throwable e) {
          Slog.e(TAG, "Failure starting Notification Manager", e);
 }

 

  注册状态栏管理和通知管理这两个服务。

2>.在StatusBarManagerService.java中，有addNotification，removeNotification,updateNotification等方法用于管理传递给他的通知对象。这个类是一些管理方法，实际执行相关动作的是在IStatusBar.java里面，这个是framework/base/core/java/com/android/internal/statusbar/IStatusBar.aidl自动生成的用于IPC的类。

拿addNotification方法示范：

 public IBinder addNotification(StatusBarNotification notification) {
                 synchronized (mNotifications) {
                 IBinder key = new Binder();
                 mNotifications.put(key, notification);
                 if (mBar != null) {
                 try {
                     mBar.addNotification(key, notification);
                   } catch (RemoteException ex) {
                }
             }
             return key;
         }
       }

 这里的mBar其实就是IStatusBar的实例

 volatile IStatusBar mBar;

 为了防止NPE，每次使用mBar都先判断是否为null，mBar是在方法registerStatusBar中传递进来的。

 public void registerStatusBar(IStatusBar bar, StatusBarIconList iconList,
             List<IBinder> notificationKeys, List<StatusBarNotification> notifications) {
         enforceStatusBarService();

         Slog.i(TAG, "registerStatusBar bar=" + bar);
         mBar = bar;
         synchronized (mIcons) {
             iconList.copyFrom(mIcons);
         }
         synchronized (mNotifications) {
             for (Map.Entry<IBinder,StatusBarNotification> e: mNotifications.entrySet()) {
                 notificationKeys.add(e.getKey());
                 notifications.add(e.getValue());
             }
         }
         }

 framework/base/packages/SystemUI/src/com/android/systemui/statusbar/CommandQueue.java实现IStatusBar.java接口，

framework/base/packages/SystemUI/src/com/android/systemui/statusbar/StatusBarService.java提供IStatusBar相关服务。

CommandQueue.java中，IStatusBar.java里面对应的方法是用callback的形式调用的，callback的实现当然就在对应的服务提供类也就是StatusBarService.java中提供的啦。

CommandQueue.java中：

 public void addNotification(IBinder key, StatusBarNotification notification) {
         synchronized (mList) {
             NotificationQueueEntry ne = new NotificationQueueEntry();
             ne.key = key;
             ne.notification = notification;
             mHandler.obtainMessage(MSG_ADD_NOTIFICATION, 0, 0, ne).sendToTarget();
                 //这句话对应的mHandler执行语句是：
                 //  final NotificationQueueEntry ne = (NotificationQueueEntry)msg.obj;
             // mCallbacks.addNotification(ne.key, ne.notification);
                 //也就是调用回调函数里面的addNotification。
         }
     }

 在StatusBarService.java中：

 mCommandQueue = new CommandQueue(this, iconList);//StatusBarService实现了CommandQueue中的CommandQueue.Callbacks接口
         mBarService = IStatusBarService.Stub.asInterface(
                 ServiceManager.getService(Context.STATUS_BAR_SERVICE));
         try {
                 //将IStatusBar实现类的对象传递到StatusBarManagerService.java中，这里的mCommandQueue就是上面对应的mBar啦。
             mBarService.registerStatusBar(mCommandQueue, iconList, notificationKeys, notifications);
         } catch (RemoteException ex) {
             // If the system process isn't there we're doomed anyway.
         }

 

 最终执行状态栏更新通知等事件都是在实现的CommandQueue.Callbacks里面执行。还是以addNotification为例：

 

 public void addNotification(IBinder key, StatusBarNotification notification) {
         boolean shouldTick = true;
         if (notification.notification.fullScreenIntent != null) {
             shouldTick = false;
             Slog.d(TAG, "Notification has fullScreenIntent; sending fullScreenIntent");
             try {
                 notification.notification.fullScreenIntent.send();
             } catch (PendingIntent.CanceledException e) {
             }
         }

         StatusBarIconView iconView = addNotificationViews(key, notification);
         if (iconView == null) return;
           //。。。以下省略N字。

大致流程就是:调用StatusBarManagerService.java中的addNotification方法->（mBar不为空的话）执行mBar.addNotification(key, notification);->对应的是CommandQueue中的addNotification(IBinder key, StatusBarNotification notification)->CommandQueue中的mCallbacks.addNotification(ne.key, ne.notification);->StatusBarService中的addNotification。

 

3>.上面是提供相关功能的一些类，具体的notification的管理类是framework/base/services/java/com/android/server/NotificationManagerService.java，从该类的定义public class NotificationManagerService extends INotificationManager.Stub可以知道

他是用来实现接口中INotificationManager中定义的相关方法并向外部提供服务的类。主要向外提供public void enqueueNotificationWithTag(String pkg, String tag, int id, Notification notification,int[] idOut)方法。该方法实际上是调用public void enqueueNotificationInternal(String pkg, int callingUid, int callingPid,String tag, int id, Notification notification, int[] idOut)，他里面提供了notification的具体处理方法。

摘取部分代码片段看看： 

 

 

 if (notification.icon != 0) {
                 StatusBarNotification n = new StatusBarNotification(pkg, id, tag,
                         r.uid, r.initialPid, notification);
                 if (old != null && old.statusBarKey != null) {
                     r.statusBarKey = old.statusBarKey;
                     long identity = Binder.clearCallingIdentity();
                     try {
                         mStatusBar.updateNotification(r.statusBarKey, n);
                     }
                     finally {
                         Binder.restoreCallingIdentity(identity);
                     }
                 } else {
                     //省略。。。

 

 当判断好需要更新通知的时候调用mStatusBar.updateNotification(r.statusBarKey, n);方法，这个就是StatusBarManagerService.java中的addNotification方法，这样就进入上面所说的处理流程了。

 

 

4>. 在3中的NotificationManagerService.java是管理notification的服务，服务嘛就是用来调用的，调用他的就是大家熟悉的NotificationManager了。

在NotificationManager.java中，有一个隐藏方法，用来得到INotificationManager接口对应的服务提供类，也就是NotificationManagerService了。

 

 

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

 再看看更熟悉的notify方法，其实是执行：

 

 public void notify(String tag, int id, Notification notification)
     {
         int[] idOut = new int[1];
         INotificationManager service = getService();
         String pkg = mContext.getPackageName();
         if (localLOGV) Log.v(TAG, pkg + ": notify(" + id + ", " + notification + ")");
         try {
             service.enqueueNotificationWithTag(pkg, tag, id, notification, idOut);
             if (id != idOut[0]) {
                 Log.w(TAG, "notify: id corrupted: sent " + id + ", got back " + idOut[0]);
             }
         } catch (RemoteException e) {
         }
     }

 service.enqueueNotificationWithTag(pkg, tag, id, notification, idOut);也就是3中提到的那个对外公开的服务方法了，这样就进入了上面提到的处理流程了。

分析比较好的博客地址：http://blog.csdn.net/longwuxu/article/details/25542199