CloudKit - 调用performQuery后加载数据

Question

使用CloudKit完成performQuery操作后重新加载我的表。问题是使用来自云的数据重新加载表。我的数据很好，没有任何问题。

我发现这个帖子我认为会解决它，但我不知道何时调用它以及如何调用它。

Wait For Asynchronous Operation To Complete in Swift

- 代码

import UIKit
import CloudKit

class DownloadTableViewController: UITableViewController {

    var rooms: [String] = []
    var appliance: [String] = []
    let container = CKContainer.defaultContainer()
    var publicDatabase: CKDatabase?
    var currentRecord: CKRecord?
    let publicDB = CKContainer.defaultContainer().privateCloudDatabase


    var receivedString = myHouse.houseData

    override func viewDidLoad() {
        super.viewDidLoad()
        rooms.removeAll()
        appliance.removeAll()
        reloadMyData()
        //performQuery()
        // Uncomment the following line to preserve selection between presentations
        // self.clearsSelectionOnViewWillAppear = false

        // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
        // self.navigationItem.rightBarButtonItem = self.editButtonItem()
    }
    override func viewDidAppear(animated: Bool) {
        rooms.removeAll()
        appliance.removeAll()
        reloadMyData()
        print("Calling query")
        performQuery()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        print("Received memory warning")
        // Dispose of any resources that can be recreated.
    }

    // MARK: - Table view data source

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 1
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of rows
        if rooms.count == 0 {
            return 1
        }
        else {
            return rooms.count
        }
    }


    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCellWithIdentifier("downloadTableCell", forIndexPath: indexPath)
            as! DownloadTableViewCell
        print(" rooms: \(rooms.count)")
        // Configure the cell...
        if rooms.count == 0 {
            cell.downloadLabel.text = "Waiting for Cloud Data....."
        }
        else {
            cell.downloadLabel.text = rooms[indexPath.row] + " - " + appliance[indexPath.row]
        }
        return cell
    }


    /*
    // Override to support conditional editing of the table view.
    override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
    // Return false if you do not want the specified item to be editable.
    return true
    }
    */

    /*
    // Override to support editing the table view.
    override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
    if editingStyle == .Delete {
    // Delete the row from the data source
    tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
    } else if editingStyle == .Insert {
    // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
    }
    }
    */

    /*
    // Override to support rearranging the table view.
    override func tableView(tableView: UITableView, moveRowAtIndexPath fromIndexPath: NSIndexPath, toIndexPath: NSIndexPath) {

    }

    func performQuery() {
        //let tempCloudID = "B16AEB76-AA36-491A-B3C7-775602466ECB"
        //application(application: UIApplication!, performFetchWithCompletionHandler completionHandler: ((UIBackgroundFetchResult) -> Void)!)
        // NOT SURE HOW TO CALL THE ABOVE LINE OR WHERE TO CALL IT
        let tempCloudID = myCurrentHouse[5]
        let predicate = NSPredicate(format: "CloudID = %@", tempCloudID)
        //let sort = NSSortDescriptor(key: "Room", ascending: true)

        let query = CKQuery(recordType: "ImagesSaved", predicate: predicate)
        query.sortDescriptors = [NSSortDescriptor(key: "Room", ascending: true)]
        publicDB.performQuery(query, inZoneWithID: nil , completionHandler: ({ results, error in
            if(error != nil) {
                dispatch_async(dispatch_get_main_queue()) {
                    self.notifyUser("Cloud Access Error", message: error!.localizedDescription)
                    print("Error")
                    self.rooms.removeAll()
                    self.appliance.removeAll()
                    self.rooms.append("Cloud Error")
                    self.appliance.append("Connected?")
                    //self.reloadMyData()


                }
            }
            else {
                if results!.count > 0 {
                    self.rooms.removeAll()
                    self.appliance.removeAll()
                    for record in results! {
                        self.rooms.append(record.objectForKey("Room") as! String)
                        self.appliance.append(record.objectForKey("Appliance") as! String)
                        print("I have results from query")
                    }
                    self.reloadMyData()
                }
                else {
                    print("query returned with no results")
                    self.rooms.removeAll()
                    self.appliance.removeAll()
                    self.rooms.append("No Data")
                    self.appliance.append(" ")
                    self.reloadMyData()

                }
            }
        }))
        //self.reloadMyData()
    }
    func notifyUser(title: String, message: String) -> Void {
        let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
        let cancelAction = UIAlertAction(title: "OK", style: .Cancel, handler: nil)
        alert.addAction(cancelAction)
        self.presentViewController(alert, animated: true, completion: nil)
    }
    func reloadMyData() {
        print("Reloading data \(self.rooms.count)")
        self.tableView.reloadData()
    }
}