Iphone CKQueryOperation获取最后一条记录

我需要拿到cloudkit中的最后一张唱片。这是我的密码：

 CKContainer *container = [CKContainer containerWithIdentifier:containerID];
    CKDatabase *publicDatabase = [container publicCloudDatabase];
    CKQuery *query = [[CKQuery alloc] initWithRecordType:recordType
                                               predicate:[NSPredicate predicateWithFormat:@"TRUEPREDICATE"]];
     CKQueryOperation *queryOp = [[CKQueryOperation alloc] initWithQuery:query];

    queryOp.desiredKeys = @[@"record.recordID.recordName"];
    queryOp.recordFetchedBlock = ^(CKRecord *record)
    {
        //do something
    };

     queryOp.queryCompletionBlock = ^(CKQueryCursor *cursor, NSError *error)
    {
        NSLog(@"CKQueryCursor  error %@", error);
    };

    queryOp.resultsLimit = CKQueryOperationMaximumResults;
    [publicDatabase addOperation:queryOp];

我的问题是如何修改代码以获得cloudkit中的最后一条记录

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我非常感谢您的帮助

您可以在创建数据上进行升序排序，然后只需请求1个这样的结果（代码是Swift）：

添加排序：

query.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]

限制结果：

queryOp.resultsLimit = 1

Objective-C版本

    NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO];
query.sortDescriptors = @[sortDescriptor];

有一项记录：

queryOp.resultsLimit = 1;

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设置resultsLimit似乎对我不起作用，但是无论如何都要设置它，并使用时间戳或记录创建日期对结果进行排序。然后将结果存储在数组中，并根据排序顺序使用第一个或最后一个项目

    CKContainer *container = [CKContainer containerWithIdentifier:containerID];
    CKDatabase *publicDatabase = [container publicCloudDatabase];
    CKQuery *query = [[CKQuery alloc] initWithRecordType:recordType predicate:[NSPredicate predicateWithFormat:@"TRUEPREDICATE"]];

    NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO];
    query.sortDescriptors = @[sortDescriptor];

    CKQueryOperation *queryOp = [[CKQueryOperation alloc] initWithQuery:query];
    queryOp.desiredKeys = @[@"record.recordID.recordName"];
    queryOp.recordFetchedBlock = ^(CKRecord *record)
    {
        //do something
        recordArray.append(record)
    };

    queryOp.queryCompletionBlock = ^(CKQueryCursor *cursor, NSError *error)
    {
        NSLog(@"CKQueryCursor  error %@", error);
        let myLastRecord = recordArray[recordArray.count - 1]
    };

    queryOp.resultsLimit = CKQueryOperationMaximumResults;
    [publicDatabase addOperation:queryOp];

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结果限制似乎对我没有影响