如何异步动态UITableView的负荷图像？ [英] How to async load images on dynamic UITableView?

问题描述

现在我与图像和标签自定义单元格。后来我通过打印这些细胞：

Now I have a custom cell with the image and label. Later I print these cells by:

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

    let cell:customCell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! customCell

    var url = NSURL(string: postCover[indexPath.row])

    if let data = NSData(contentsOfURL: url!) { 
        cell.cellImage.image = UIImage(data: data)
    }

    var title = postTitle[indexPath.row]

    cell.cellLabel.text = title

    let indexPath = tableView.indexPathForSelectedRow()

    return cell
}

和当我打开一个应用程序，并滚动它冻结。我怎样才能修复这个bug？

and when I open an app and scroll it freezes. How can I fix this bug?

我读到它，我必须用异步加载图像在我的tableView，但不要我加载它们异步了？

I read about it, that I must use async image loading in my tableView, but don't I load them async already?

我搜索，想想4-5天并没有什么。谁能给我一些建议，好吗？

I searched and think about it 4-5 days and nothing. Can anyone give me some tips, please?

推荐答案

您可以使用异步调度图像的下载每个单元的GCD AS-

You can schedule the downloading of image asynchronously for each cell using GCD as-

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

    let cell:customCell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! customCell

    var url = NSURL(string: postCover[indexPath.row])

cell.imageView.image = nil;
        dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
        dispatch_async(queue, ^(void) {

            NSData *imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:parsedData[@"imageLR"]];

            UIImage* image = [[UIImage alloc] initWithData:imageData];
            if (image) {
                 dispatch_async(dispatch_get_main_queue(), ^{
                     if (cell.tag == indexPath.row) {
                         cell.imageView.image = image;
                         [cell setNeedsLayout];
                     }
                 });
             }
        });

return cell
}

有关雨燕，你可以做这样

for Swift you can do so as

if let data = self.cache.objectForKey(urlString) as? NSData {
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)) {
            let image = UIImage(data: data)
            dispatch_async(dispatch_get_main_queue()) {
                cell.imageView.image = image;
            }
        }

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