检索更改的CloudKit记录时识别记录更改类型

Question

我正在尝试使用CloudKit同步和本地CoreData完成一个应用程序。大多数操作都像预期的那样工作，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。如有任何指导，将不胜感激。

下面是我认为可以配置的代码，以识别我需要对CoreData进行的编辑类型。Xcode 10.2.1 iOS 12.2 Swift (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

解决方案是正在使用的操作版本上的单独方法。我已经收到通知了，只是不知道它们是更新、创建还是删除。可以通过搜索recordName( UUID)的核心数据来处理更新和创建。如果找到，然后编辑，如果没有创建。问题是删除-使用fetchRecordZoneChangesCompletionBlock无法识别删除。然而，操作族有一个仅用于报告删除( operation.recordWithIDWasDeletedBlock )的方法。我修改了以前的代码，并添加了如下所示的删除代码。

我的单个数据库订阅涵盖了整个私有数据库，因此不需要订阅每种记录类型。

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

Answer 2

我不太擅长斯威夫特，但我会在目标c中发布，这样你就可以把它转换成斯威夫特。

1. 首先，如果要通知某个记录是否已被编辑、删除或创建，则需要注册推送通知。
2. 然后订阅更新，在didFinishLaunchingWithOptions中添加此块

    - (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];
            }
        }];
        }
    }

1. 您将在didReceiveRemoteNotification中收到通知

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

    }



    }
            }];
     }
    }

}