Notification framework层的处理流程分析(3)

        } 
        } 
 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：
Java代码 
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：
Java代码 
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.