CloudKit 订阅未在 iOS10 上保存

Question

我正在关注'CloudKit Best Practices' WWDC talk关于添加订阅的内容，iOS10 中似乎有所改变。

下面的代码返回“成功！”，但我的“AllChanges”订阅从未出现在 CloudKit 仪表板的订阅类型中。

我正在使用 Xcode 8 beta 6。

    let subscription = CKDatabaseSubscription(subscriptionID:"AllChanges")
    let notificationInfo = CKNotificationInfo()
    notificationInfo.shouldSendContentAvailable = true
    subscription.notificationInfo = notificationInfo

    let operation = CKModifySubscriptionsOperation(subscriptionsToSave: [subscription], subscriptionIDsToDelete: [])
    operation.modifySubscriptionsCompletionBlock =  {
        (modifiedSubscriptions: [CKSubscription]?, deletedSubscriptionIDs: [String]?, error: Error?) -> Void in

        if error != nil {
            print(error!.localizedDescription)
        } else {
            print("Success!")
        }
    }
    operation.qualityOfService = .utility
    privateDatabase.add(operation)

Answer 1

我在 CKDatabaseSubscription 上遇到过同样的问题，其他许多人也遇到过：

• https://forums.developer.apple.com/thread/53546
• https://forums.developer.apple.com/thread/61267
• https://forums.developer.apple.com/thread/64071
• https://forums.developer.apple.com/thread/63917

我先列出一些注意事项，以防他们解释您的问题：

• 订阅通常不会出现在“开发者”CloudKit 仪表板中（它们存在，但未显示 - 最简单的测试方法是重命名订阅并查看 CloudKit 是否抱怨重复订阅）
• 推送通知不会发送到模拟器

解决方案：

解决此问题的方法是创建一个自定义私有区域并将我的所有数据保存到该区域（仅适用于私有数据库）。然后我会收到关于该区域的任何更改的推送通知。

您将需要创建区域（-检查 CKAccountStatus = .available 和 -before- 任何记录保存）：

let operation = CKModifyRecordZonesOperation(recordZonesToSave: [CKRecordZone(zoneName: "MyCustomZone")], recordZoneIDsToDelete: nil)
operation.modifyRecordZonesCompletionBlock = { (savedRecordZones: [CKRecordZone]?, deletedRecordZoneIDs: [CKRecordZoneID]?, error: Error?) in
    if let error = error {
        print("Error creating record zone \(error.localizedDescription)")
    }
}
privateDatabase?.add(operation)

然后在保存记录时使用该区域：

let record = CKRecord(recordType: "MyRecordType", zoneID: CKRecordZone(zoneName: "MyCustomZone")) 
// you can save zone to CKRecordID instead, if you want a custom id

然后跳过 CKFetchDatabaseChangesOperation（因为我们已经知道我们的区域），并使用 CKFetchRecordZoneChangesOptions 代替：

let options = CKFetchRecordZoneChangesOptions()
options.previousServerChangeToken = myCachedChangeToken
let operation = CKFetchRecordZoneChangesOperation(
    recordZoneIDs: [myCustomZoneId],
    optionsByRecordZoneID: [myCustomZoneId: options]
)
operation.fetchAllChanges = true
operation.recordChangedBlock = { (record: CKRecord) -> Void in
        ... do something
}
operation.recordWithIDWasDeletedBlock = { (recordId: CKRecordID, recordType: String) -> Void in
        ... do something
}
operation.recordZoneFetchCompletionBlock = { (recordZoneId, changeToken, tokenData, isMoreComing, error) in
    if let error = error {
        print("Error recordZoneFetchCompletionBlock: \(error.localizedDescription)")
        return
    }
    myCachedChangeToken = changeToken
}
privateDatabase?.add(operation)