Notification framework层的处理流程分析

google了一段时间发现没人写notification在framework中具体怎么实现的，感到很奇怪，是我搜索有问题？哎，不管了，反正工作需要，自己琢磨琢磨吧。

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：
Java代码
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：
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());
            }
        }
        }
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);
&n

补充：移动开发 , Android ,