异步tableview更新

Question

我正在使用uitableview来显示我生成的一些数据。数据被分成特定的类，然后在每个单元格中使用。当页面加载时，它显示一个空白的表视图，但是一旦我点击搜索栏并键入一个字母，单元格就会出现在屏幕上。我相信这可能是一个异步问题？我想发布一张图片，但我需要10个代表点:( 我应该这样，只有当我从服务器上获取数据时才会发生这种情况。当我硬编码数据时，它会在初始加载屏幕上显示它

代码：

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    if tableView == self.searchDisplayController!.searchResultsTableView {
        return self.filteredProducts.count
    } else {
        return self.products.count
    }
}

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    //ask for a reusable cell from the tableview, the tableview will create a new one if it doesn't have any
    let cell = self.tableView.dequeueReusableCellWithIdentifier("Cell") as UITableViewCell!

    var product : Product
    // Check to see whether the normal table or search results table is being displayed and set the Candy object from the appropriate array
    if tableView == self.searchDisplayController!.searchResultsTableView {
        product = filteredProducts[indexPath.row]
    } else {
        product = products[indexPath.row]
    }

    // Configure the cell
    cell.textLabel!.text = product.title

    println(product.title)
    println(cell)
    cell.accessoryType = UITableViewCellAccessoryType.DisclosureIndicator

    return cell
}

func filterContentForSearchText(searchText: String, scope: String = "All") {
    self.filteredProducts = self.products.filter(
        {
            ( product : Product) -> Bool in
            var categoryMatch = (scope == "All") || (product.category == scope)
            var stringMatch = product.title.rangeOfString(searchText)
            return categoryMatch && (stringMatch != nil)
    })
}

func searchDisplayController(controller: UISearchDisplayController!, shouldReloadTableForSearchString searchString: String!) -> Bool {
    let scopes = self.searchDisplayController!.searchBar.scopeButtonTitles as [String]
    let selectedScope = scopes[self.searchDisplayController!.searchBar.selectedScopeButtonIndex] as String
    self.filterContentForSearchText(searchString, scope: selectedScope)
    return true
}

func searchDisplayController(controller: UISearchDisplayController!,
    shouldReloadTableForSearchScope searchOption: Int) -> Bool {
        let scope = self.searchDisplayController!.searchBar.scopeButtonTitles as [String]
        self.filterContentForSearchText(self.searchDisplayController!.searchBar.text, scope: scope[searchOption])
        return true
}

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    self.performSegueWithIdentifier("productDetail", sender: tableView)
}

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
    if segue.identifier == "productDetail" {
        let productDetailViewController = segue.destinationViewController as ProductDetailViewController


        if sender as UITableView == self.searchDisplayController!.searchResultsTableView {
            let indexPath = self.searchDisplayController!.searchResultsTableView.indexPathForSelectedRow()!
            let destinationTitle = self.filteredProducts[indexPath.row].title
            productDetailViewController.title = destinationTitle
            productDetailViewController.productPriceText = String(self.products[indexPath.row].title)
            productDetailViewController.productTitleText = self.products[indexPath.row].title
            productDetailViewController.productDescriptionText = self.products[indexPath.row].description
        } else {
            let indexPath = self.tableView.indexPathForSelectedRow()!
            let destinationTitle = self.products[indexPath.row].title
            productDetailViewController.title = destinationTitle
        }

    }