swift - 如何将 NS 操作 QOS = .UserInteractive 添加到查询功能

Question

我一直在浏览大量论坛和教程，希望能够加快我的 cloudkit 应用程序的速度 - (至少)似乎答案归结为将服务质量功能设置为“UserInteractive”。目前，更新具有 3 条记录的表 Controller 大约需要 2/3 秒，每条记录只有一个字符串变量，通过标签显示。据我所知，将 QoS 设置为用户交互将迫使 UI 更新得更快。但是，我不确定如何正确地完整实现 qos 代码。就目前情况而言，这是我的代码，需要 2/3 秒才能加载。

  func fetch()
    {   
    let publicDatabase = CKContainer.defaultContainer().publicCloudDatabase
    let predicate = NSPredicate(value: true)
    let query = CKQuery(recordType: "Dining", predicate: predicate)

    publicDatabase.performQuery(query, inZoneWithID: nil) { (results, error) -> Void in
        if (error != nil)
        {
            print("Error" + (error?.localizedDescription)!)
        }
        else
        {
            for result in results!
            {    
              self.categories.append(result)
            }

            dispatch_async(dispatch_get_main_queue(), { () -> Void in         
              self.tableView.reloadData()
            })
        }
        }
}
     fetch()   
}

因此，为了获得更快的 UI 响应，我可以实现这样的东西吗？

 func fetch()
    {   
    let publicDatabase =     CKContainer.defaultContainer().publicCloudDatabase
    let predicate = NSPredicate(value: true)
    let query = CKQuery(recordType: "Dining", predicate: predicate)

    publicDatabase.performQuery(query, inZoneWithID: nil) { (results, error) -> Void in
        if (error != nil)
        {
            print("Error" + (error?.localizedDescription)!)
        }
        else
        {
            for result in results!
            {    
              self.categories.append(result)
            }

            let qualityOfServiceClass = QOS_CLASS_UserInteractive
    let Queue = dispatch_get_global_queue(qualityOfServiceClass, 0)
    dispatch_async(Queue, {
    print("This is run on the background queue")

   dispatch_async(dispatch_get_main_queue(), { () -> Void in
   self.tableView.reloadData()
})
})

        }
        }
}
     fetch()   
}

Answer 1

按照以下方式使用查询操作:

func fetch(){
    let publicDatabase = CKContainer.defaultContainer().publicCloudDatabase
    let predicate = NSPredicate(value: true)
    let query = CKQuery(recordType: "Dining", predicate: predicate)
    let queryOperation = CKQueryOperation(query: query)
    queryOperation.qualityOfService = .userInteractive
    queryOperation.recordFetchedBlock = {(record: CKRecord) -> Void in
        // Do things with record
    queryOperation.queryCompletionBlock = {(cursor, error) in
        // Handle error and do things

        }
     }
publicDB.add(queryOperation)
}

请参阅有关 NSOperation 及其实例属性 QualityofService 的文档