在iOS 5中，通知由Notification Center管理。您必须在通知中心（以编程方式）注册您的应用程序，或（以非编程方式）转到设置>通知并选择适当的设置，例如启用通知中心，选择提醒方式等。

In iOS 5, notifications are managed by Notification Center. You have to register your application with the Notification Center (programmatically), or (non-programmatically) go to Settings > Notifications and select appropriate settings i.e. enable Notification Center, select Alert Style, and others.

您可以使用以下代码注册您的应用程序使用Notification Center（以编程方式），将其放入 applicationDidFinishLaunching：：

You can use following piece of code to register your application with Notification Center (programmatically), by putting it in applicationDidFinishLaunching::

// Although Register For Remote Notifications is not required for Local Notifications,
// but in iOS 5's Notifications, we have to register otherwise the system doesn't register/recognize
// the notifications posted from the application. Note that this behavior is not documented
// as of Oct 2011, and it's possible that it's a bug and will be handled in the future releases.

[[UIApplication sharedApplication] registerForRemoteNotificationTypes: 
 UIRemoteNotificationTypeAlert |
 UIRemoteNotificationTypeSound];

HTH。