Alamofire图像：未为af_setImageWithURL设置占位符图像

I am using af_setImageWithURL Alamofire API to fetch the table cell images and pass a default placeholder image:

我正在使用af_setImageWithURL Alamofire API来获取表格单元格图像并传递默认的占位符图像:

let defaultImage = UIImage(named:"myImage")
cell.imageView.af_setImageWithURL(imageURL, placeholderImage:defaultImage, imageTransition: .CrossDissolve(0.1))

Problem: When my image does not exists at the downloading path, cell do not show the default image as well. When I scroll the table up & down (to purge and re-use the same cell) then it shows up.

问题:当下载路径中不存在我的图像时,单元格也不显示默认图像。当我向上和向下滚动表格(清除并重新使用同一个单元格)时,它会显示出来。

EDIT:

Noticed this is happening after dequeuing the cell, I reset the image first and then call Alamofire. If I comment out below line, it works fine but then I am running into a risk of showing old product image if both image URL and default images are not available.

注意到这是在将单元格出列后发生的,我首先重置图像然后调用Alamofire。如果我在下面注释掉它,它运行正常,但如果图像URL和默认图像都不可用,那么我将面临显示旧产品图像的风险。

cell.imageView.image = nil

Anybody faced similar issue, please advise.

任何人都面临类似的问题,请指教。

2 个解决方案

#1

You need to make sure you cancel your request and also nil out the image in prepareForReuse. Otherwise you can run into a few different problems. Here's the ImageCell class in the iOS Example in AFI.

您需要确保取消您的请求,并在prepareForReuse中删除图像。否则你可能会遇到一些不同的问题。这是AFI中iOS示例中的ImageCell类。

class ImageCell: UICollectionViewCell {
    class var ReuseIdentifier: String { return "org.alamofire.identifier.\(type(of: self))" }
    let imageView: UIImageView

    // MARK: - Initialization

    override init(frame: CGRect) {
        imageView = {
            let imageView = UIImageView(frame: frame)

            imageView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
            imageView.contentMode = .center
            imageView.clipsToBounds = true

            return imageView
        }()

        super.init(frame: frame)

        contentView.addSubview(imageView)

        imageView.frame = contentView.bounds
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    // MARK: - Lifecycle Methods

    func configureCell(with URLString: String, placeholderImage: UIImage) {
        let size = imageView.frame.size

        imageView.af_setImage(
            withURL: URL(string: URLString)!,
            placeholderImage: placeholderImage,
            filter: AspectScaledToFillSizeWithRoundedCornersFilter(size: size, radius: 20.0),
            imageTransition: .crossDissolve(0.2)
        )
    }

    override func prepareForReuse() {
        super.prepareForReuse()

        imageView.af_cancelImageRequest()
        imageView.layer.removeAllAnimations()
        imageView.image = nil
    }
}

Cheers. ????

#2

As I mentioned, this works well if I do not set cell image view' image nil just before Alamofire call. So, I am now setting the cell image view' image to nil only when default image is nil.

正如我所提到的,如果我在Alamofire调用之前没有设置单元格图像视图'image nil,这很有效。所以,我现在只在默认图像为零时将单元格图像视图'图像设置为nil。

cell.imageView.image = nil