使用reloadRowsAtIndexPaths或reloadSections会导致Tableview Cell闪烁

Question

我尝试使用reloadRowsAtIndexPaths或reloadSections重新加载特定的tableView单元格，当该单元格中的分段开关发生变化时（这反过来又改变了UIScrollView内的UICollectionView那个细胞）。使用此选项会导致最后一个tableView单元格（与重新加载的单元格无关）闪烁：单元格的背景会短暂变为黑色。最后一个tableView单元格与另一个不同，因为它包含backgroundView（参见下图）。 tableView中的所有单元格都清晰，//tableView cellForRowAtIndexPath case .cellToReload: let cell = tableView.dequeueReusableCellWithIdentifier("graphs", forIndexPath: indexPath) as! WeatherTableViewCell cell.selectionStyle = UITableViewCellSelectionStyle.None let segmentControl = cell.viewWithTag(1) as! UISegmentedControl segmentControl.selectedSegmentIndex = segment segmentControl.addTarget(self, action: "segmentAction:", forControlEvents: .ValueChanged) cell.graph.delegate = self cell.graph.showsHorizontalScrollIndicator = false if segment == 0 || segment == 1 { cell.graph.contentSize.width = cell.frame.width * 2.0 } else { cell.graph.contentSize.width = cell.frame.width } cell.graph.contentSize.height = cell.graph.frame.height let ConditionsView = UIView(frame: CGRectMake(20, 0, cell.graph.contentSize.width, cell.graph.contentSize.height)) cell.backgroundColor = UIColor.clearColor() switch (segment) { //create new view and add as a subview to cell.graph case .flickeringCell: let cell = tableView.dequeueReusableCellWithIdentifier("weeklyWeatherCell", forIndexPath: indexPath) as! WeatherTableViewCell cell.selectionStyle = UITableViewCellSelectionStyle.None cell.forecastCollectionView.delegate = self cell.forecastCollectionView.dataSource = self cell.forecastCollectionView.reloadData() cell.forecastCollectionView.tag = indexPath.row cell.forecastCollectionView.showsHorizontalScrollIndicator = false cell.backgroundColor = UIColor.clearColor() cell.forecastCollectionView.backgroundView = cell.backgroundView cell.forecastCollectionView.backgroundColor = cell.backgroundColor return cell func segmentAction(sender: UISegmentedControl) { let path = NSIndexSet(index: 1) switch sender.selectedSegmentIndex { case 0: segment = 0 tableView.reloadSections(path, withRowAnimation: .Fade) case 1: segment = 1 tableView.reloadSections(path, withRowAnimation: .Fade) case 2: segment = 2 tableView.reloadSections(path, withRowAnimation: .Fade) default: break } } //Table background func createGradientForTable { let gradientLayer = CAGradientLayer() ... gradientLayer.startPoint = CGPoint(x: 0, y: 0) gradientLayer.endPoint = CGPoint(x: 0, y: 1) let backgroundView = UIView(frame: sender.tableView.frame) backgroundView.layer.insertSublayer(gradientLayer, atIndex: 0) sender.tableView.backgroundView = backgroundView } 控制背景颜色渐变。

       #####################
        # Uploading multiple# 
        #     Images        #
        #####################


        $files = $_FILES;
        $count = count($_FILES['uploadfile']['name']);
        for($i=0; $i<$count; $i++)
                {
                $_FILES['uploadfile']['name']= $files['uploadfile']['name'][$i];
                $_FILES['uploadfile']['type']= $files['uploadfile']['type'][$i];
                $_FILES['uploadfile']['tmp_name']= $files['uploadfile']['tmp_name'][$i];
                $_FILES['uploadfile']['error']= $files['uploadfile']['error'][$i];
                $_FILES['uploadfile']['size']= $files['uploadfile']['size'][$i];
                $this->upload->initialize($this->set_upload_options());//function defination below
                $this->upload->do_upload('uploadfile');
                $upload_data = $this->upload->data();
                $name_array[] = $upload_data['file_name'];
                $fileName = $upload_data['file_name'];
                $images[] = $fileName;

                }
              $fileName = $images;

带有UICollectionView的TableView单元格：

Answer 1

我删除了那个视觉效果视图，并通过向collectionView添加背景来实现相同的效果。视觉效果视图是闪烁的，而不是单元格或其中的其他视图。我通过编辑实现了与视觉效果视图相同的效果：

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

包括：

collectionView.backgroundColor = UIColor.whiteColor().colorWithAlphaComponent(0.25)

Answer 2

记住在主线程上更新UI以调度和异步任务时：

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)) { 
    dispatch_async(dispatch_get_main_queue()) { 
        self.tableView.reloadData() 
    } 
}