Question

调用了 getService，如下：

  private static INotificationManager sService;

  static private INotificationManager getService() {
    if (sService != null) {
      return sService;
    }
    sService = INotificationManager.Stub.asInterface(ServiceManager.getService("notification"));
    return sService;
  }

得到 INotificationManager 服务，再调用 enqueueToast 方法，参数有三个，包名，TN，时间。INofiticationManager 接口的具体实现类是 NotificationManagerService 类，源码位置： frameworks\base\services\core\java\com\android\server\notification\NotificationManagerService.java