INotificationManager的实现
INotificationManager

interface INotificationManager
{
void enqueueNotification(String pkg, int id, in Notification notification, inout int[] idReceived);
void cancelNotification(String pkg, int id);
void cancelAllNotifications(String pkg);

void enqueueToast(String pkg, ITransientNotification callback, int duration);
void cancelToast(String pkg, ITransientNotification callback);
}

实现类是:com.android.server.NotificationManagerService