Notification framework层的处理流程分析(2)

  拿addNotification方法示范：
Java代码 
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
Java代码 
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。
Java代码 
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()); 
            }