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：

 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。