我在Swift中使用Parse.com，但无法更新TableView

Question

Using the Parse is MBaaS in Swift is making a program that displays the character that you enter in the TextField to TableView,but Part to be updated by pulling the TableView does not go well .

override func viewDidLoad() {
super.viewDidLoad()
self.loadData()
// DataSource
tableView.dataSource = self
// Delegate
tableView.delegate = self
self.pullrefresh()
}
func loadData() {
var query:PFQuery = PFQuery(className: "Comment")
query.orderByDescending("createdAt")
query.findObjectsInBackgroundWithBlock{(objects: [AnyObject]!, error: NSError!) -> Void in
    if (error != nil){
        //error
    }
    for object in objects {
        self.comments.addObject(object)
    }
   self.tableView.reloadData()
}
}
func pullrefresh(){
self.refreshControl = UIRefreshControl()
self.refreshControl.attributedTitle = NSAttributedString(string: "↓pull")
self.refreshControl.addTarget(self, action: "refresh:", forControlEvents: UIControlEvents.ValueChanged)
self.tableView.addSubview(refreshControl)
}
func refresh(sender:AnyObject){
self.loadData()
self.refreshControl.endRefreshing()}

And I wrote this kind of program , but when it pulled to update , you will see the same content .How do should I do to the text that is displayed on another screen to update only those that have not been displayed without displaying ?

Answer 1

Use Grand Central Dispatch. In query.findObjectsInBackgroundWithBlock , replace this:

for object in objects {
     self.comments.addObject(object)
}
self.tableView.reloadData()

with this:

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)) {
        // Task
        for object in objects {
            self.comments.addObject(object)
        }
        dispatch_async(dispatch_get_main_queue()) {
            // UI
            self.tableView.reloadData()
    }
}

Answer 2

Try updating it on the main thread:

dispatch_async(dispatch_get_main_queue(),{
     self.tableView.reloadData()
});