检索更改的 CloudKit 条记录时识别记录更改的类型

Question

我正在尝试使用 CloudKit 同步和本地 CoreData 来完成一个应用程序。大多数操作都按预期工作，但我找不到确定 CloudKit 报告的更改类型的方法。我得到了更改的记录，但我需要知道更改是编辑、新记录还是删除。任何指导将不胜感激。

这是我认为可以配置为识别我需要对 CoreData 进行的编辑类型的代码片段。 Xcode10.2.1iOS12.2Swift（最新）

func fetchZoneChangesInZones( _ zones : [CKRecordZone.ID], _ completionHandler: @escaping (Error?) -> Void) {

    var fetchConfigurations = [CKRecordZone.ID : CKFetchRecordZoneChangesOperation.ZoneConfiguration]()

    for zone in zones {
        if let changeToken = UserDefaults.standard.zoneChangeToken(forZone: zone) {
            let configuration = CKFetchRecordZoneChangesOperation.ZoneConfiguration(previousServerChangeToken: changeToken, resultsLimit: nil, desiredKeys: nil)
            fetchConfigurations[zone] = configuration
        }//if let changeToken

    }//for in

    let operation = CKFetchRecordZoneChangesOperation(recordZoneIDs: zones, configurationsByRecordZoneID: fetchConfigurations)

    operation.fetchAllChanges = true

    var changedPatients = [CKRecord]()
    var changedCategory1s = [CKRecord]()

    //I thought that I should be able to query for the change type here and make separate arrays for each change type
    operation.recordChangedBlock = { record in
        if record.recordType == "Patient" {
            changedPatients.append(record)
        }
    }//recordChangedBlock

    operation.fetchRecordZoneChangesCompletionBlock = { [weak self] error in
        for record in changedPatients {
            //my actions here - need to choose new, changed or delete
            self!.saveCKRecordToCoreData(record: record)
        }//for record in

        completionHandler(error)

    }//fetchRecordZoneChangesCompletionBlock

    operation.recordZoneFetchCompletionBlock = { recordZone, changeToken, data, moreComing, error in
        UserDefaults.standard.set(changeToken, forZone: recordZone)
    }//recordZoneFetchCompletionBlock

    privateDatabase.add(operation)

}//fetchZoneChangesInZones

Answer 1

我在 swift 中表现不佳，但我会 post 在 objective c 中，因此您可以将其转换为 swift

首先，如果您想在记录被编辑、删除或创建时收到通知，您需要注册推送通知。
然后订阅更新将此块添加到 didFinishLaunchingWithOptions


    - (void)subscribeToEventChanges
    {
        BOOL isSubscribed = [[NSUserDefaults standardUserDefaults] boolForKey:@"subscribedToUpdates"];
        if (isSubscribed == NO) {
        NSPredicate *predicate = [NSPredicate predicateWithFormat:@"TRUEPREDICATE"];

        CKQuerySubscription *subscription = [[CKQuerySubscription alloc] initWithRecordType:@"Patient" predicate:predicate options:CKQuerySubscriptionOptionsFiresOnRecordCreation | CKQueryNotificationReasonRecordDeleted | CKQueryNotificationReasonRecordUpdated];

        CKNotificationInfo *CKNotification=[[CKNotificationInfo alloc]init];
        CKNotification.shouldSendContentAvailable=YES;
        CKNotification.soundName=@"";
        subscription.notificationInfo=CKNotification;
        CKDatabase *publicDatabase = [[CKContainer containerWithIdentifier:@"your container identifir"] privateCloudDatabase];

        [publicDatabase saveSubscription:subscription completionHandler:^(CKSubscription * _Nullable subscription, NSError * _Nullable error) {
            if (error) {
                // Handle here the error
            } else {
                // Save that we have subscribed successfully to keep track and avoid trying to subscribe again
                [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"subscribedToUpdates"];
                [[NSUserDefaults standardUserDefaults] synchronize];
            }
        }];
        }
    }

您将在 didReceiveRemoteNotification

这是一段代码


    - (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo {

      CKNotification *cloudKitNotification = [CKNotification notificationFromRemoteNotificationDictionary:userInfo];
        if (cloudKitNotification.notificationType == CKNotificationTypeQuery) {
            CKQueryNotification *queryNotification = (CKQueryNotification *)cloudKitNotification;

            if (queryNotification.queryNotificationReason == CKQueryNotificationReasonRecordDeleted) {
                // If the record has been deleted in CloudKit then delete the local copy here

            } else {
                // If the record has been created or changed, we fetch the data from CloudKit
                CKDatabase *database;
                if (queryNotification.databaseScope) {
                    database = [[CKContainer containerWithIdentifier:@"your container identifier"] privateCloudDatabase];
                }

    [database fetchRecordWithID:queryNotification.recordID completionHandler:^(CKRecord * _Nullable record, NSError * _Nullable error) {
                    if (error) {
                        // Handle the error here
                    } else {

                  if (queryNotification.queryNotificationReason == CKQueryNotificationReasonRecordUpdated) {
                            // Use the information in the record object to modify your local data
    }else{
                            // Use the information in the record object to create a new local object

    }



    }
            }];
     }
    }

}

Answer 2

该解决方案是针对正在使用的操作版本的单独方法。我已经收到通知，只是无法判断它们是更新、创建还是删除。只需在核心数据中搜索 recordName（这是一个 UUID）即可处理更新和创建。如果找到，则编辑，如果没有创建。问题是删除 - 使用 fetchRecordZoneChangesCompletionBlock 无法识别删除。但是，操作族有一个方法只是报告删除 - operation.recordWithIDWasDeletedBlock。我修改了之前的代码，添加了删除代码如下图

我的单一数据库订阅覆盖了整个私有数据库，因此没有必要订阅每个记录类型。

operation.fetchRecordZoneChangesCompletionBlock = { error in
        for record in changedPatients {

            //search for the record in coredata
            if self.isSingleCoreDataRecord(ckRecord: record) {
                //if found - then modify
                self.saveUpdatedCloudKitRecordToCoreData(record: record)
            } else {
                //else add new
                self.saveCKRecordToCoreData(record: record)
            }

        }//for record in

        completionHandler(error)

}//fetchRecordZoneChangesCompletionBlock


operation.recordWithIDWasDeletedBlock = { (recordID, recordType) in

        //delete the core data record here
        let ckRecordToDelete = CKRecord(recordType: recordType, recordID: recordID)

        self.removeOnePatientRecordFromCoreData(ckRecord: ckRecordToDelete)

}//recordWithIDWasDeletedBlock

检索更改的 CloudKit 条记录时识别记录更改的类型

Identify Type of Record Change when Retrieving Changed CloudKit Records

core-data

ios

cloudkit