AFNetworking的setImageWithURLRequest在滚动后将图像设置在错误的单元格中（iOS，Swift） [英] AFNetworking's setImageWithURLRequest sets image in wrong cell after scroll (iOS, Swift)

问题描述

我将表与 dequeueReusableCellWithIdentifier 和 afnetworking + uiimageview 一起使用。我的某些单元格有图片，有些则没有。如果在加载图像之前滚动表，则成功块会将图像放置在重用的错误单元格中。例如，图像在＃2单元格中，但是在滚动之后它出现在＃8单元格中，因为＃8在那一刻位于第二位置。是否可以将 setImageWithURLRequest 与 dequeueReusableCellWithIdentifier 一起使用？

I use table with dequeueReusableCellWithIdentifier and afnetworking+uiimageview. Some of my cells have images, some haven't. If I scroll my table before an image has loaded, success block will put image in reused wrong cell. For example image was in cell #2, but after scroll it appears in cell number #8 because #8 was on second position in that moment. Is it possible to use setImageWithURLRequest with dequeueReusableCellWithIdentifier together?

我的代码：

    let cell = tableView.dequeueReusableCellWithIdentifier("simpleCell", forIndexPath: indexPath) as UITableViewCell!
    cell.textLabel.text = fields[indexPath.row]["name"] as String
    cell.imageView.image = nil
    if let image = fields[indexPath.row]["image"] as? String {
        if (image != "") {
            let image_url = NSURL(string: image)
            let url_request = NSURLRequest(URL: image_url)
            let placeholder = UIImage(named: "no_photo")
            cell.imageView.setImageWithURLRequest(url_request, placeholderImage: placeholder, success: { [weak cell] (request:NSURLRequest!,response:NSHTTPURLResponse!, image:UIImage!) -> Void in
                if let cell_for_image = cell {
                    cell_for_image.imageView.image = image
                    cell_for_image.setNeedsLayout()
                }
            }, failure: { [weak cell]
               (request:NSURLRequest!,response:NSHTTPURLResponse!, error:NSError!) -> Void in
                if let cell_for_image = cell {
                    cell_for_image.imageView.image = nil
                    cell_for_image.setNeedsLayout()
                }
            })
        }
    }
    return cell

对不起，如果我的问题重复了另一个。我发现了很多类似的问题，但没有找到解决方法。我尝试添加重新加载

sorry if my question duplicates another. I found a lot of similar questions, but I haven't found solution. I tried to add reload

tableView.reloadRowsAtIndexPaths([indexPath], withRowAnimation: UITableViewRowAnimation.None)

进入我的成功块，但这无济于事。

into my success block, but it doesn't help.

更新：
我也注意到，在所有单元格都有图像的情况下，我没有这个问题。如果我正确理解原因，则是：当尝试请求新图像时，AFNetworking正在中止对同一单元的先前请求。但是，如果我没有在单元格中成像，它不会中止。我该如何手动？

UPDATE: I also noticed, that I have not this problem in cases when all my cells has an images. If I understood correctly the reason is: AFNetworking is aborting previous request for the same cell, when try to request new image. But If I haven't image in cell it will not abort. How can I do it manually?

推荐答案

当表格视图重用该单元格时，图像下载仍在背景。完成后，单元格指向具有不同内容的重用单元格。

When the cell is reused by the table view, the image download is still processing in the background. When it completes, cell points to a reused cell with different content.

您有两个选择：

1. 在 cell.imageView.image之后在图像视图上调用 cancelImageRequestOperation = nil


2. 在完成处理程序中，不要引用 cell ;而是使用数据模型从表视图中请求正确的单元格。

1. Call cancelImageRequestOperation on the image view after cell.imageView.image = nil
2. In the completion handler, don't refer to cell; instead use your data model to request the correct cell from the table view.

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