CloudKit:按创建日期排序查询结果

Question

从CloudKit加载项目时,我想按创建日期订购结果.我相信现在它正在按记录的第一个属性进行排序.

func loadItems() {
    let predicate = NSPredicate(value: true)
    let query = CKQuery(recordType: "Items", predicate: predicate)
    db.performQuery(query, inZoneWithID: nil) { (results, error) -> Void in
        if error != nil {
            println(error.localizedDescription)
        }

        dispatch_async(dispatch_get_main_queue()) { () -> Void in
            items = results as [CKRecord]
            self.tableView.reloadData()
            println("items: \(items)")
        }
    }
}

Answer 1

这就是我要找的东西:

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

Answer 2

这是Objective-C解决方案.它在Swift中的工作方式类似.

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"TRUEPREDICATE"];
CKDatabase *privateDatabase = [self.myContainer privateCloudDatabase];
CKQuery *query = [[CKQuery alloc] initWithRecordType:@"command" predicate:predicate];
query.sortDescriptors = [NSArray arrayWithObject:[[NSSortDescriptor alloc]initWithKey:@"creationDate" ascending:true]];

有了这个,您可能会收到以下错误消息:

CKError 0x12e874f10:"无效参数"(12/2016); server message ="Field'___createTime'未标记为可排序"; uuid = 468AC2A4-24D6-4A56-81BB-6A2A8027DC15; container ID ="iCloud.com.xxx"

因此,只需在仪表板中对其进行排序: