这是iOS 11.0中的一个问题

根据我的测试：

这在设备上的Xcode 9.2 / iOS 11.2.1中工作正常(不是模拟器)

重置模拟器后第一次工作,随后不起作用,但是在设备上它重复工作.

码：

let queue = OperationQueue()

func requestPermissions(for permissions: CKApplicationPermissions,completionHandler: @escaping (CKApplicationPermissionStatus,Error?) -> ()) {

    CKContainer.default().requestApplicationPermission(permissions) { status,error in

        if let error = error {

            print("Error for requesting \(permissions) - \(error)")
        }

        let statusMessage : String

        switch status {

        case .granted:
            statusMessage = "Granted"
        case .denied:
            statusMessage = "Denied"
        case .couldNotComplete:
            statusMessage = "Could not complete"
        case .initialState:
            statusMessage = "Initial state"
        }

        print("Permission - \(statusMessage)")

        completionHandler(status,error)
    }
}


private func discoverAllUsers() {

    let operation = CKDiscoverAllUserIdentitiesOperation()

    operation.userIdentityDiscoveredBlock = { userIdentity in

        print("userIdentity = \(userIdentity)")
    }

    operation.discoverAllUserIdentitiesCompletionBlock = { error in

        if let error = error {

            print("Discover all users Error: \(error) ")
        }
        else {
            print("Discover all users completed successfully")
        }
    }

    queue.addOperation(operation)
}