Question

我正在使用Swift，我试图为我的表添加一个拉动刷新功能，但它不会停止刷新我认为我可能有一个问题我的endrefresher也当它刷新时不会停止当你再次刷新应用程序崩溃时出现NSexception错误。我如何结束刷新并刷新页面，如果再次拉下来避免崩溃？继承我的代码：

class HomePage: UITableViewController  {

    var images = [UIImage]()
    var titles = [String]()
    var imageFile = [PFFile]()
    var votingObjects: [PFObject] = []
    var objectIds = [""]

    var refresher: UIRefreshControl!


    override func viewDidLoad() {
        super.viewDidLoad()


        refresher = UIRefreshControl()

        refresher.attributedTitle = NSAttributedString(string: "Pull to refresh")

        refresher.addTarget(self, action: "refresh", forControlEvents: UIControlEvents.ValueChanged)

        self.tableView.addSubview(refresher)

        func refresh() {

        println(PFUser.currentUser())

        println(PFUser.currentUser())

        var query = PFQuery(className:"Post")
        query.orderByDescending("createdAt")
        query.limit = 15
        query.findObjectsInBackgroundWithBlock {
            (objects: [AnyObject]?, error: NSError?) -> Void in
            if error == nil  {
                println("Successfully retrieved \(objects!.count) scores.")
                println(objects!)
                for objectRow in objects! {
                    let object = objectRow as! PFObject


                    if let objectIds = object["objectId"] as? String {
                        self.objectIds.append(objectIds)
                    }
                    if let title = object["Title"] as? String {
                        self.titles.append(title)
                    }
                    if let imgFile = object["imageFile"] as? PFFile {
                        self.imageFile.append(imgFile)
                    }
                    self.votingObjects.append(object)
                    self.refresher.endRefreshing()

                }
                dispatch_async(dispatch_get_main_queue(), {
                    self.tableView.reloadData() // Updating the tableView on the main thread - important. Do some research on Grand Central Dispatch :)

                })
            } else {
                println(error)
                // Error
            }
        }
    }

        refresh()

    }

Answer 1

在此处设置刷新器以在完成时调用函数refresh：

refresher.addTarget(self, action: "refresh", forControlEvents: UIControlEvents.ValueChanged)

所以我们需要实现这个功能：

func refresh(){
    println("Refresh")
    refresher.endRefreshing()
}

现在将调用此函数并且刷新将停止

刷新没有结束，再次拉下来时会出错

1 个答案: