您的应用程序无法知道它是否已被卸载。此外，我不相信苹果会告诉你你的应用程序是否已卸载。

There isn't a way that your app will know if it is uninstalled. Also I do not believe there is anyway Apple will tell you if your app is uninstalled.

苹果推送通知服务的反馈服务确实提供了一种了解设备是否无法接收通知的方法。但是，这并不保证设备已卸载，只是因为任何原因无法接收推送通知。

Apples Push Notification Service's FeedBack Service does provide a way to know if a device cannot receive a notification. However this does not guarantee that the device was uninstalled, only that it, for whatever reason, can not receive push notifications.

如果提供商尝试向应用程序发送推送通知，但设备上不再存在该应用程序，设备会向Apple推送通知服务报告该事实。当用户卸载应用程序时，通常会发生这种情况。如果设备报告应用程序的失败传递尝试，则APN需要某种方式通知提供者，以便它可以避免向该设备发送通知。这样做可以减少不必要的消息开销并提高整体系统性能。

If a provider attempts to deliver a push notification to an application, but the application no longer exists on the device, the device reports that fact to Apple Push Notification Service. This situation often happens when the user has uninstalled the application. If a device reports failed-delivery attempts for an application, APNs needs some way to inform the provider so that it can refrain from sending notifications to that device. Doing this reduces unnecessary message overhead and improves overall system performance.

为此，Apple推送通知服务包含一个反馈服务，APN通过每个应用程序的设备列表不断更新有失败的交付尝试。

For this purpose Apple Push Notification Service includes a feedback service that APNs continually updates with a per-application list of devices for which there were failed-delivery attempts.